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I tried to make guacamole the other day and it completely failed because some of the avocados that I bought were not ripe. How can I know which avocados to pick in order to make good guacamole? | I've been trying to ignore my burning desire to make some guacamole because every time I go to the supermarket to buy avocados I can't manage to pick out good ones. They always either become too soft before I have a chance to do anything with them or are hard and not very tasty. How can I tell when an avocado is perfectly ripe? |
Is there an easy way to accomplish something like this: I am aware this is scanned, what I want is the random ink distribution and character placement. | Is there a way to simulate imperfections of some of the older books in LaTeX? Like the missing pieces of letters, extra splotches of ink and such? Here is an interesting artifact: P.S.: I guess one way would be to get an old printer haha :-0 |
It is the default version of the imagemagick program convert that comes with ubuntu 14.04 ip-173-31-35-119:~ [prod]$ convert -version Version: ImageMagick 6.7.7-10 2014-03-06 Q16 http://www.imagemagick.org Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC Features: OpenMP In another shell I have downloaded the latest version of source code and compiled locally. If I start a new shell, I can see $ bash - ip-173-31-35-119:~$ convert -version Version: ImageMagick 6.9.2-3 Q16 x86_64 2015-10-07 http://www.imagemagick.org Copyright: Copyright (C) 1999-2015 ImageMagick Studio LLC License: http://www.imagemagick.org/script/license.php Features: Cipher DPC OpenMP Delegates (built-in): So the new binary is already available. In both shell, they report the same result from which and ls -l: $ which convert /usr/local/bin/convert ip-173-31-35-119:~ [prod]$ ls -l /usr/local/bin/convert -rwxr-xr-x 1 root root 6336 Oct 7 20:11 /usr/local/bin/convert Why the first shell seems to still running the old version of the binary? How can I clear this? | When looking for the path to an executable or checking what would happen if you enter a command name in a Unix shell, there's a plethora of different utilities (which, type, command, whence, where, whereis, whatis, hash, etc). We often hear that which should be avoided. Why? What should we use instead? |
Here is the code below: #include <stdio.h> int main() { printf("Stack Overflow"); main(); } After compiling and executing this program it will print "Stack Overflow" until its stack overflows. Here, I know what a stack overflow means, that means it will print until memory is full. My question is which memory is it? What is the size of the stack that is overflowing? | Programming language books explain that value types are created on the stack, and reference types are created on the heap, without explaining what these two things are. I haven't read a clear explanation of this. I understand what a stack is. But, Where and what are they (physically in a real computer's memory)? To what extent are they controlled by the OS or language run-time? What is their scope? What determines the size of each of them? What makes one faster? |
Let $\alpha\in\mathbb C$. Recall that $\mathbb Q[\alpha]$ = {${f(\alpha) : f(X) \in \mathbb Q[X]}$} and that $\mathbb Q[\alpha]$ is a vector space over $\mathbb Q$. Suppose that $\mathbb Q[\alpha]$ is finite dimensional as a vector space over $\mathbb Q$. Prove that $\alpha$ is algebraic over $\mathbb Q$. I'm not sure where to start with this proof, so any help is much appreciated. Thanks! | If $[L:K]$ is finite, then $[L:K]$ is algebraic. The author's proof is to simply state that given $[L:K] = n$, then ${1, x, x^2, ... , x^n}$, for any $x$ in $L$, would contain $n+1$ elements, so it must be linearly dependent over $K$. First of all, why must ${1, x, x^2, ... , x^n}$ be linearly dependent over $K$? I do undertsand that if $L=K(a_1, ... , a_m)$, and we pick an non-algebraic $a_i$, then ${1, a_i, a_i^2, ... , a_i^n}$ would be, by definition, linearly dependent over $K$. But how can we know that this works with all the elements in $L$? Second of all, even if we find that $c_0+ c_1x+c_2x^2 + ... + c_{m-1}≠0$, for some $x$ in $L$, $c_i$ in $K$, why would this mean that $[L:K]=∞$? I asked this question a couple days ago, though I didn't explain my doubt in such detail as in this post. Anyway, the replies asked if I understood the meaning of being 'linearly dependent over a field $F$'. My understanding is that a set ${b_1, ... , b_n}$ is linearly independent over $F$ if each element in $F$ can be written as $f_1b_1+...+f_nb_n$ (so that the different combinations of $b_i$ form the whole $F$) and that the only way $f_1b_1+...+f_nb_n=0$ is for all the $b_i$ to be $0$ (so that we make sure all the elements in the set are needed to map create $F$). I guess they asked me that question because is rather obvious why the author's proof works. Yet I don't know why, but it isn't that obvious to me. I would really appreciate any help/thoughts. |
So I'm doing a bit of practise in database design, and a question arose that I couldn't figure out how to correct. I'm pretty new at this, so I'm not the best but here it goes. So I want to create two different tables, one called Team, and one called Player. These tables are pretty different from one another. I then want another table called Challenge, which I want to reference either Team or Player. Basically there are competitions, and they are either competed individually, or as a team. I want a foreign key to reference Team, if its a team challenge, or Player if its individual. I can't combine the two tables, as they contain very different elements. Im just a bit confused as to how to do it. Can I have just one foreign key, that will reference one table or another. Or shall I have two, with one null. Or can I add another ID key in the Team and Player. And then in Challenge if a new Type key indicated its a group, it'll reference Team, and if its individual, it references Player. Again, pretty new at this, so hope I made sense. | Well here's my problem I have three tables; regions, countries, states. Countries can be inside of regions, states can be inside of regions. Regions are the top of the food chain. Now I'm adding a popular_areas table with two columns; region_id and popular_place_id. Is it possible to make popular_place_id be a foreign key to either countries OR states. I'm probably going to have to add a popular_place_type column to determine whether the id is describing a country or state either way. |
I have not worked with 3d coordinate systems for a while and this is giving me a bit of a struggle. I have the coordinates of four points in XYZ. Two points I use to generate the line AB and the other two I use to generate line CD. I would like to find the closest XYZ coordinate on AB to line CD and the closest XYZ coordinate on CD to line AB. My idea was to find the equation for the perpendicular line between AB and CD and then find the intersection of this new line with AB and CD. However, I do not really know where to begin. If anyone could help that would be very much appreciated | I have two arbitrary lines in 3D space, and I want to find the distance between them, as well as the two points on these lines that are closest to each other. Naturally, this only concerns the skew case, since the parallel and intersecting cases are trivial. I know how to find the distance, as the question was asked before and answered . I haven't found a good explanation on how to find the two points that determine that distance, though. So specifically, given two lines $$L_1=P_1+t_1V_1$$ $$L_2=P_2+t_2V_2$$ I would like to find two points $X_1$ on $L_1$ and $X_2$ on $L_2$ such that the distance between $X_1$ and $X_2$ is minimal. |
Can someone clarify whether or not a capacitor blocks current at DC? – Schematic created using | I am confused with this! How does a capacitor block DC? I have seen many circuits using capacitors powered by a DC supply. So, if capacitor blocks DC, why should it be used in such circuits? Also, the voltage rating is mentioned as a DC value on the capacitor. What does it signify? |
I am trying to change a node color of Tikz node with only option as: \documentclass[10pt,xcolor=dvipsnames,xcolor=table]{beamer} \usepackage{tikz} \usetikzlibrary{positioning,arrows} \usetikzlibrary{decorations.pathmorphing} \usetikzlibrary{decorations.markings} \begin{document} \begin{frame} \centering \begin{tikzpicture}[sibling distance=12em, level distance=3em, every node/.style = {shape=rectangle, rounded corners, draw, align=center, font=\footnotesize, top color=Red, bottom color=Red, color=white}]] \node {Foo} child {node{Bar1}} \only<1>{child {node{Bar2}} \only<2>{child[top color=Blue] {node{Bar2}} child {node{bar21}} child {node{bar22}}}; \end{tikzpicture} \end{frame} \end{document} This works fine when no only thing is involved, but with only, its giving error: Runaway argument? \centering \begin {tikzpicture}[sibling distance=12em, level distance\ETC. ! File ended while scanning use of \frame. <inserted text> \par <*> mwe.tex What I am doing wrong here? Please help. | I have a diagram of 4 nodes in my beamer slide. \begin{figure}[h] \begin{centering} \begin{tikzpicture}[system/.style={draw,rectangle,rounded corners=3,minimum width=2cm,text width=1.8cm,text centered}] \node [system] (fe) {Feature Extraction}; \node [system] (am) [right=of fe] {Acoustic Model}; \node [system] (lm) [right=of am] {Language Model}; \node [system] (d) [below=of lm] {Decoder}; \draw[->] (fe) |- (am); \draw[->] (am) |- (d); \draw[->] (lm) -- (d.north); \end{tikzpicture} \end{centering} \end{figure} How can I in a second slide "highlight" one of the nodes, like I can do with <alert@n> for a item in a list? With highlighting I mean for example giving a color and thickening the lines. |
I had previously hosted my domain in a different instance in a different aws account but for some reason I had to delete that aws account and create a new one. I am now trying to host my domain in the new instance. So I went to my registrar`s account and deleted all the nameservers from the domain name and added the new nameserver. Then I added my domain into the hosted zone in aws. After waiting for 2 3 hrs my domain is still now working but if I visit the public IP it works. I have edited the /etc/hosts file and added domainname.com there and also I have edited the /sites-available/default and added server { # passenger_ruby /usr/bin/passenger_free_ruby; rails_env development; # add this if you get error like “Incomplete response received from application” from nginx / passenger listen 80 default_server; server_name fuitter.com, *.fuitter.com; root /usr/share/nginx/html/maggie/public/; # You must explicitly set 'passenger_enabled on', otherwise # Passenger won't serve this app. passenger_enabled on; } I have restarted my nginx server but still it is not working. security group then, in inbound rule I have set HTTP to anywhere and SSh to custom ip and in outbound i have set all traffic to anywhere. Is there anything wrong with this? | I have updated a domain name DNS zone on 123-reg.co.uk where I bought the domain name. I have only updated blog A record to different hosting(IP) On my PC home (windows) or another PC in the same network (MAC or phone) when I visit the blog.domain.com still shows old IP address (hosting). But when I connect to 4g on my phone or try from different network, they visit new IP (hosting) I did ipconfig /flushdns I have restarted the router at home. I have cleared browser cache Why do you think the reason is? How can I solve this? Thanks. |
I have to go to school. I have to go to the school. Which is correct sentence? Can we use article before the word "School"? | Why is this sentence wrong about the article usage? Don't be late for the school. I was told that the correct sentence is Don't be late for School. |
$a,b,c \geq 0$ and $a^2+b^2+c^2+abc=4$ prove that $ab+bc+ac-abc \leq 2$ can any one help me with this problem,I believe Dirichlet's theorem is the key for this sorry for making mistake over and over again,but i'm certain that the inequality is true now. | Let $a,b,$ and $c$ be nonnegative real numbers such that $a^2+b^2+c^2+abc = 4$. Prove that $$0 \leq ab + ac + bc - abc \leq 2.$$ I tried using rearrangement to get $a^2+b^2+c^2+abc = 4 \geq ab+bc+ac+abc$. Then I just need to show that $0\leq ab + ac + bc - abc$ and $4-2abc \leq 2$. I am not sure if this method will work, though. |
I got two JavaScript objects. I want to compare both objects to one another. If object 1 has a key which is missing in object 2 add this key to object 2. But this must also be the case if object 2 has a key which is missing in object 1. So for example, object 1 looks like this. var object_1 = { "Address": "Address", "AccessDeniedText": "You do not have access to the page you requested.<br>Use the navigation menu on the left to select a page you want to open.", "Basket": "Shopping cart", "BasketVAT": "VAT {0}" ... }; object 2 looks like this. var object_2 = { "Address": "Address", "Basket": "Shopping cart", ... }; In object 2 the key AccessDeniedText and BasketVAT are missing. Expected result What i now want is to have an new object, lets say object 3 that would now output the following. var object_3 = { "Address": "Address", "AccessDeniedText": "", // I can fill this missing text "Basket": "Shopping cart", "BasketVAT": "" // I can fill this missing text } I tried to use $.each() and for(key in object). However, this made my whole browser crash. Not so wierd, because each object has more then a 1000 rows. I also tried to awnser of this question: It didn't work for me. Is there a simple way to do it? Without my browser crashing of the heavy payload? I dont care using jQuery. | I need to be able to merge two (very simple) JavaScript objects at runtime. For example I'd like to: var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' } obj1.merge(obj2); //obj1 now has three properties: food, car, and animal Does anyone have a script for this or know of a built in way to do this? I do not need recursion, and I do not need to merge functions, just methods on flat objects. |
Normally, we say "He was caught with his mistress." Here, we know that the male is a married person. The meaning is clear. If he is not married, then we can say "He was caught with his girlfriend." But, how to convey that a married female was caught with her lover. a female was caught with her ____. Saying that, she was caught with her boyfriend does not clear the air that she is married or not. So, is there any male-gender specific word opposite of mistress and clears the air that female is cheating her husband? I googled few words: lover, sweetheart, loved one, love, beloved, darling, dearest, young man, man friend, man, escort, wooer, admirer etc. And, from Wikipedia, "Paramour" is sometimes used, but this term can apply to either partner in an illicit relationship, so it is not exclusively male. But, none fits the requirement. | The mistress definition, Oxford dictionary a woman having an extramarital sexual relationship, esp. with a married man I am looking for the male equivalent of 'mistress' as defined above. Some sources on the net come up with 'master' and 'mastress'. But I could not find both words in dictionary as male equivalent of mistress. So, any male equivalents of mistress in formal English? |
It started few days ago. I'm running sudo apt update command and it never ends. Terminal output is Get:1 http://ru.archive.ubuntu.com/ubuntu xenial InRelease [247 kB] Hit:2 http://archive.canonical.com/ubuntu xenial InRelease Hit:3 http://ppa.launchpad.net/attente/java-non-latin-shortcuts/ubuntu xenial InRelease Hit:4 http://ppa.launchpad.net/webupd8team/sublime-text-3/ubuntu xenial InRelease Ign:5 http://dl.google.com/linux/chrome/deb stable InRelease Hit:6 http://ru.archive.ubuntu.com/ubuntu xenial-updates InRelease Get:7 http://security.ubuntu.com/ubuntu xenial-security InRelease [94,5 kB] Hit:8 http://dl.google.com/linux/chrome/deb stable Release Hit:9 http://ru.archive.ubuntu.com/ubuntu xenial-backports InRelease Fetched 341 kB in 2s (150 kB/s) While this proccess system fan speed is boosted on my laptop and it's kinda annoying to listen to this. There is no excessive cpu activity though. Can you guys hint me why it happens? | I tried to install crossover and after downloading the .deb from their website, I followed the steps as indicated when opening it with Ubuntu Software Centre: On 64-bit flavors of Debian and some Ubuntu variants, first open a terminal and run sudo dpkg --add-architecture i386 ; sudo apt-get update Since I have Ubuntu 16.04 LTS 64 bit I perform the command. But when copying and pasting that command into my terminal, it stopped at Fetched 535kb in 7sec and stalled there for about 20 minutes. I ended up closing it and tried to run both commands separately but after doing the sudo apt-get update command it also stalls again after "Fetched XXKb in XXsec." I restarted my computer and decided to run the software updater and it stays stuck at roughly 75% for hours. |
I have a 14.4v NI CD power drill with a charger that outputs 18v 400mA (original charger for drill) but the charger supply lead no longer works. Looking to get a replacement but finding it difficult to get an exact match The charger voltage output (18v) is larger than the voltage of battery (14.4v) but does the output amps have to be the same as original (ie 400mA) if not what amps could i go upto? | Power supplies are available in a wide range of voltage and current ratings. If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify? What if I don't know the device's specs, but am replacing a previous power supply with particular ratings? Is it OK to go lower voltage, or should it always be higher? What about current? I don't want a 10 A supply to damage my 1 A device. |
I would like to know the derivation of the general equation of a conic: $$Ax^{2} + Bxy + Cy^{2} + Dx + E y + F = 0$$ I have searched over the internet, but I did not find any resource which doesn't make use of trigonometry. | Let me start with some basic definitions: Definition 1. A conic section is the curve resulting from the intersection of a plane and a cone. Definition 2. A conic section is the set of all points in a plane with the same eccentricity with respect to a particular focus and directrix. Definition 3. A conic section is the set of points $(x,y)$ satisfying the implicit formula $$Ax^2+Bxy+Cy^2+Dx+Ey+F=0$$ All these definitions are familiar to me and they are taken from a paper of Mzuri S. Handlin, Conic Sections Beyond $\mathbb{R}^2$. Now, in by university textbook I have the following theorem, Theorem. Any conic has an equation of the form $$Ax^2+Bxy+Cy^2+Dx+Ey+F=0$$ where $A,B,C,D,E$ and $F$ are real numbers and $A,B$ and $C$ are not all zero. Conversely, the set of all points in $\mathbb{R}^2$ whose coordinates $(x,y)$ satisfy an equation of the form that above, is a conic. Proof to this theorem is omitted, and reference are not included. I've been searching for a proof, but failed to find one. It seems that the above theorem make motivate us to define definition 3, right? If one can provide me a reference for the proof of the theorem or sketch guidelines for possible proof? Thank you. |
DJ didn't have the rose broach thing that Maz said he'd have, but I had the feeling that nevertheless he was the person they'd been sent to find and maybe the guy they saw with the broach had either stolen, won and bought the broach from DJ who was clearly in some kind of desperate situation (i.e. in jail and presumably broke). And Maz had said there was only one person (she knew of) that could break them on to the First Order's ship and DJ did actually do that... Is there any evidence to support DJ being the person they were looking for? Or was it just sheer luck that they happened to find the only other person that could break them in that Maz didn't know about? | In The Last Jedi, Finn and Rose are tasked with finding "the master code breaker" by Maz. They travel to the city of Canto Bight and after searching think they found him by the unique lapel pin he wears. However, they are then apprehended by the local security and thrown into jail where they meet another character (played by Benicio del Toro, I think the character is DJ?) who seems to fit the role of master code breaker based on his actions. Then later once aboard the First Order ship DJ betrays Finn and Rose by selling them out. Which seems out of character for someone loyal to Maz. So my question is who was the "real" master code breaker that Maz has told Finn and Rose about? The one they thought (based on lapel pin) or the one they actually ended up with? |
I have abstractly thought of Pure Linux as a just Linux which has only basic functions. What is the exact definition of Pure Linux? How far is it different from Ubuntu or something ? How can I download the Pure Linux image?(I want to install it on virtual machine) | I was going through an article on GNU which goes something like below There really is a Linux, and these people are using it, but it is just a part of the system they use. Linux is the kernel: the program in the system that allocates the machine's resources to the other programs that you run. The kernel is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Linux is normally used in combination with the GNU operating system: the whole system is basically GNU with Linux added, or GNU/Linux. All the so-called “Linux” distributions are really distributions of GNU/Linux. I always thought Linux as a kernel and Operating System but it looks like Linux = Linux kernel and GNU OS. Could someone point out the exact functionality of each in the "Linux" terminology we use in our day to day life. Also, according to the wiki, GNU's design is Unix-like but differs from Unix by being free software and containing no Unix code. I thought Unix is opensource. Isn't it? |
Apache 2.4.x : prefork event worker What are the conceptual differences between these three? What are the types of applications or each or situations in which each MPM is useful? | This is a about selecting the right Apache httpd MPM. I'm a little confused between the different MPMs offered by Apache - 'worker', 'event', 'prefork', etc. What are the major differences between them, and how can I decide which one will be best for a given deployment? |
I'm running some scripts to check the UFW status and would like to run sudo ufw status without having to do sudo. I was hoping to find a firewall or ufw group to add myself to, but I didn't find any. How can I allow any user X to do the ufw status without being root or asking for sudo password? UPDATE: I wanted to try to add my own file to /etc/sudoers.d/, but was lazy so decided to copy one already existing, like this: sudo cp /etc/sudoers.d/mintupdate /etc/sudoers.d/firewall_status Don't do That! You will not be able to do sudo or login again. I had to do a boot recovery. Instead use: sudo visudo -f /etc/sudoers.d/ufwstatus Now just follow the accepted answer below. | On one particular machine I often need to run sudo commands every now and then. I am fine with entering password on sudo in most of the cases. However there are three sudo commands I want to run without entering password: sudo reboot sudo shutdown -r now sudo shutdown -P now How can I exclude these commands from password protection to sudo? |
Well as you can figure out, most primates such as monkeys, gorillas and chimpanzees, have all their body covered with fur. As we know they are evolutional "relatives" to us humans, but we dont have much hair(only on the head,on the armpits, on the groin, etc.). I would like to know why this "evolution" happened in a such brief era and why. | The little amount of body hair humans have don't seem to be of much use for keeping warm. Our Simian cousins on the other hand sport thick furs. At which point during the species evolution and why did humans lose their fur? |
I have factory method that returns Type of a POCO given a Key. public static Type GetType(string key) { var name = string.format("MyPOCOClass{0},MyAssembly",key); return Type.GetType(name); } So lets say value of the Key is One and assume that the class MyPOCOClassOneexists in MyAssembly in above case i wanted type of IEnumerable<MyPOCOClassOne> How do i do that? | The title is kind of obscure. What I want to know is if this is possible: string typeName = <read type name from somwhere>; Type myType = Type.GetType(typeName); MyGenericClass<myType> myGenericClass = new MyGenericClass<myType>(); Obviously, MyGenericClass is described as: public class MyGenericClass<T> Right now, the compiler complains that 'The type or namespace 'myType' could not be found." There has got to be a way to do this. |
This is my first day after upgrading from 17.04 to 17.10. I've noticed that xdotool is not working as it used to. For example: xdotool type "Lorem ipsum" types nothing. xdotool key ctrl+shift+t doesn't open a new tab in gnome-terminal. xdotool mousemove 0 0 doesn't move the mouse. xdotool click 1 doesn't click on the stuff under the mouse. xdotool getactivewindow windowmove 100 100 doesn't move the active window and returns an error: XGetWindowProperty[_NET_ACTIVE_WINDOW] failed (code=1) xdo_get_active_window reported an error What I found is still working: xdotool search --classname Navigator windowactivate does activate the browser. xdotool getmouselocation --shell returns info about mouse position. xdotool selectwindow does allow me to click on a window to get its id. I have some scripts that rely on this tool. Any suggestion how to fix this? UPDATE: I'm using Wayland display manager. Switching to Xorg makes it work again. Is it possible to make xdotool work again while still using Wayland? | Need to bind an F key to perform Ctrl-S in Gedit and reload page browser. Can't get xdotool to find Gedit window on Ubuntu 17.10 $ xdotool search --name "Opera" | tail -1 58720257 $ xdotool search --name "Gedit" | tail -1 $ Tried changing search string to "Text Editor", file name, etc. xdotool can't find only Gedit. Works for any other desktop window. It's always the active window so finding that would also work. |
When I try to ask a question, I receive the message: Oops! Your question couldn't be submitted because: Sorry, we are no longer accepting questions from this account. And strangely when I logged in on Ubuntu everything was fine. What's the problem? | If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see: We are no longer accepting questions from this account. See to learn more. Likewise, for answers: We are no longer accepting answers from this account. See to learn more. Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked? |
I dun goofed. I thought my Windows was booting using UEFI, and I installed Ubuntu using UEFI. But now I think my Windows was booting using MBR, and GRUB can't detect it. I'm confident the disk is MBR: > sudo gdisk -l /dev/sdb GPT fdisk (gdisk) version 1.0.3 Partition table scan: MBR: MBR only BSD: not present APM: not present GPT: not present and that I'm booting via UEFI: > ls /sys/firmware/efi/ config_table fw_platform_size runtime systab efivars fw_vendor runtime-map vars How can I fix my GRUB so that it boots using MBR instead of UEFI? I've tried: Running os-prober and update-grub Running boot-repair Neither gave me a GRUB menu with Windows listed. | I have a dual boot of Windows and Ubuntu. When I switch on the machine, the BIOS does POST and after that the bootloader starts. I want to understand how the BIOS chooses which bootloader to run. I want to know the process going on between the BIOS and the bootloader in a dual boot computer. |
I know i can create an instance of a Type Paramter using the method given . But why doesnt the following statement compile? public static <E> void append(List<E> list) { E elem = new E(); // compile-time error list.add(elem); } List<String>list=new ArrayList<String>(); append(list); 1.Cant the type of E be detected based on what i pass in the method append()? Then what is Type Inference used for? 2. Even if Type Inference is not applied, then wont E elem=new E() will b converted into Object elem=new Object() at run time, which should be fine? In any case, it should work. But why it doesnt? EDIT: The duplicate qeustion that they have given link to only answers the methods by which we can create an instance of Type Parameter. It doesnt answer why this method wont work. | Is it possible to create an instance of a generic type in Java? I'm thinking based on what I've seen that the answer is no (due to type erasure), but I'd be interested if anyone can see something I'm missing: class SomeContainer<E> { E createContents() { return what??? } } EDIT: It turns out that could be used to resolve my issue, but it requires a lot of reflection-based code, as some of the answers below have indicated. I'll leave this open for a little while to see if anyone comes up with anything dramatically different than Ian Robertson's . |
The whole diagram shifts up when more children are added in the second level. Is there a nice way to adjust this automatically, so that the top nodes do not change their position from one slide to the next? For example, see slide 1 and 2 in the following code: (Thanks in advance) \documentclass{beamer} \mode<presentation>{\usetheme{Madrid}} \usepackage[style=verbose]{biblatex} \usepackage{tikz} \usetikzlibrary{shapes.geometric, arrows} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \tikzset{startstop/.style = {rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=red!30}} \tikzset{io/.style = {trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=blue!30}} \tikzset{process/.style = {rectangle, minimum width=3cm, minimum height=1cm, text centered, text width=3cm, draw=black, fill=orange!30}} \tikzset{decision/.style = {diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=green!30}} \tikzset{arrow/.style = {thick,->,>=stealth}} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \title[tikzpicture with beamer]{} \begin{document} \begin{frame}{tikzpicture}{} \begin{tikzpicture}[node distance=3cm] \node (root) [process] {root}; \node (child1) [process, below of=root, xshift=-4cm] {child1}; \draw [arrow] (root.south) -- (child1.north); \node (child2) [process, below of=root, xshift=0cm] {child2}; \draw [arrow] (root.south) -- (child2.north); \node (child3) [process, below of=root, xshift=4cm] {child3}; \draw [arrow] (root.south) -- (child3.north); \node<+(1)-> (child21) [process, below of=child2, xshift=-3cm] {child21}; \draw<.(1)-> [arrow] (child2.south) -- (child21.north); \node<+(0)-> (child22) [process, below of=child2, xshift=3cm] {child22}; \draw<.(0)-> [arrow] (child2.south) -- (child22.north); \end{tikzpicture} \end{frame} \end{document} | This question is essentially the same as one of my , except the only difference is that I am using "only" to change the text at the same location (i.e., ). In other words, I am destroying my earlier text as I go, and not adding new ones underneath the previous ones. Since the text for the first "only" is shorter than the second "only", therefore the image will shift location. I would like for the image to remain at its location. Here is an example it may not be obvious but the second image is higher up than the first. The code is here, can someone find a solution? \documentclass{beamer} \usepackage{graphicx} \title[Title]{Presentation} \author{Sandro Botticelli} \institute{Italy} \date{1484} \begin{document} \begin{frame} \begin{figure} \includegraphics[scale = 0.8]{Venus} \caption{Nascita di Venere} \end{figure} \only<1>{In the centre the newly-born goddess Venus stands nude in a giant scallop shell. Its size is purely imaginary, and is also found in classical depictions of the subject. } \only<2>{Alternative identifications for the two secondary female figures involve those also found in the Primavera; the nymph held by Zephyr may be Chloris, a flower nymph he married in some versions of her story, and the figure on land may be Flora. Flora is generally the Roman equivalent of the Greek Chloris; in the Primavera Chloris is transformed into the figure of Flora next to her, following Ovid's Fasti, but it is hard to see that such a transformation is envisaged here.} \end{frame} \end{document} |
So suppose I go to like or there's gonna be a bunch of stuff like say [UTCDate "2018.01.03"] [WhiteElo "2706"] [BlackElo "2940"] How do I get this data into a spreadsheet like column 1 is all the dates, column 2 is the corresponding white elo, column 3 black elo, col4 white username and col5 black username? Update 2: Fixed now. see the 'json' vs the 'preformed'. WOW. Update 1: It appears Mike Steelson has an answer , where the code is given as =arrayformula( regexextract(split( substitute(substitute(substitute(getDataJSON(A1;"/games";"/pgn");"[";"");"]";"");"""";"") ;char(10));"\s.*") ) with an example given here It appears there's a problem when it gets to the case of chess960 only. Consider for example : Replacing 'gmwso' with the player's username will yield a weird output. i imagine the output will be messier for mixed chess960 and chess. | Both and chess.com have the feature to play the variant live. However, only lichess has a graph showing how your live chess960 rating has changed over time. Lichess also shows other statistics like highest, lowest, best wins, worst losses, average opponent rating, etc. (chess.com does have this for correspondence chess960 though.) I could create my own graph and statistics in Excel/Google Sheets by manually recording each game's date and my rating afterwards indicated beside my username, but... Question: Is there a way to obtain, or what in general is the way to go about obtaining, ratings after each chess960 game using some kind of script that sees a player's public profile and then extracts the data? I have a feeling this kind of script has been done before even if this was not specifically done for chess.com's live chess960. The script doesn't have to graph (pretty easy to do once you have to the data: just use excel/google sheets). I just need the script to collect all the dates and rating numbers for each line of the user's games. Update 2: Fixed now. see the 'json' vs the 'preformed'. WOW. Update 1: It appears Mike Steelson has an answer , where the code is given as =arrayformula( regexextract(split( substitute(substitute(substitute(getDataJSON(A1;"/games";"/pgn");"[";"");"]";"");"""";"") ;char(10));"\s.*") ) with an example given here It appears there's a problem when it gets to the case of chess960 only. Consider for example : Replacing 'gmwso' with the player's username will yield a weird output. i imagine the output will be messier for mixed chess960 and chess. |
I'm using Minecraft Java version 1.12.2. I have a fake player called Alive that shows the amount of players still active inside the arena. When a player loses a round that counter will lower by 1. When the count reaches 1 the game will stop (don't worry about that; I already know how to handle this). The problem I'm having with this is that I don't know how to tell a command block to keep an active count of the number of Alive players. Does anyone know how to count players within a radius and set that for the score of the fake player Alive? | I want to run a command when there are only 10 entities left. I know you can use /execute unless entity to detect when all matching mobs have died, but it doesn't work if you want to run a command when there are for example 10 entities left. A command like /execute if entity @e[limit=10] does not work, it also triggers if there is only one entity. Such a counting system could also be used to determine once there is only one player left in an arena, meaning they have won a battle or similar. |
I can understand the need to audit editing etc and when I get the first user and first answer privileges the system seemed to work well. However I just unlocked close votes and now it seems that every third vote I do is an audit. That is just annoying and feels like an enormous waste of my time and doesn't really encourage me to put any effort into trying to clear the enormous backlog of close votes stack overflow has. So I was already getting a bit annoyed by it, and then I got an audit: The answer from OldCurmudgeon came up in the audit to be reviewed and it was indeed an excellent answer. However the process failed because I went and read the question and saw the answer was already there! So I hit flag to report that the answer was a duplicate of an already posted answer...and got told that I should be paying more attention? So I get told I should pay more attention because I was paying too much attention? What does the audit failed actually mean? Beyond being a slap in the face for trying to help what does one or two failed audits actually do in real terms? | I just had a review queue audit question "fail" because I clicked "Close" on a post that the community felt should be left open. This particular meta question is about the close vote review queue, but the same principle should apply elsewhere. Audits are good. I see what the idea behind them is, and for the very most part I agree wholeheartedly. However, just clicking "Close" in the review queue doesn't actually do anything. All it does is bring up a dialog box with a bunch of options for how to close the question. Nothing of significance happens until you actually vote to close. I often pull up that dialog box to refresh my memory if I am uncertain what is considered on topic by the community on various sites. For example, product recommendation questions are off topic on SuperUser but not on Unix & Linux. On the other hand, on Unix & Linux non-reproducible problems are specifically off topic, which they are not on SuperUser (though posts about nonreproducible problems may be off topic for other reasons). Since there can be quite a bit of overlap between the sites, sometimes I'd rather just check to be sure before deciding to leave a question open. There have been a number of times when actually checking has made me decide that a question really is not off topic where it was posted; it might have been off topic on a different site, but it's fine on this one according to the earlier judgement of the community. However, unless you really go out of your way, before you're able to make that determination you have already failed the audit. If the issue at stake is (as has been indicated previously) that in voting, that can easily be detected (handled, mitigated, fixed, ...) by putting in some random votes in the audit "close" dialog box, or not displaying any votes at all in the case of audits. Or even possibly showing exactly such a set of "wrong reason" votes. The reason for that being that what one should be trying to catch is people taking action based on incorrect judgment, which is quite different from just clicking on the "Close" button quite possibly without even a clear intention (see above about the memory refresher). Hence: In a review queue audit, only actually doing something that would ordinarily result in taking action should cause you to pass or fail the audit. That is, for example, clicking "Close" in the outer view shouldn't fail you even if the question should be left open, although clicking "Vote To Close" in the resultant dialog box should. |
According to refractive index's formula, we say that speed of light is other mediums is smaller than that of speed of light in air/vacuum. What quantum mechanical effects govern the increase in speed of light when it moves from another medium back into air/vacuum? | As I learned today in school, my teacher told me that when light enters a glass slab it slows down due to the change in density and it speeds up as it goes out of the glass slab. This causes a lateral shift and the light emerges out from the point different than that from where it should have actually emerged from. Okay so what I mean to ask is, when light enters point A on glass slab and emerges from point C why does the light speed up? Where does it get the energy it has lost when it entered the glass slab? P.S.: Also, if I place a very very very large glass slab and make a beam of light pass through it will the light never come out as all the energy was lost in place of heat? |
I have a list that needs to contain a variable number of independent sets. When I run the following piece of code, I want to add the string "testing" to only the first set. numberOfSets = 3 test = [set()]*numberOfSets test[0].add("testing") print test However, when I print test, it shows three identical sets that all contain testing. How can I set up my list so I can separately access each set? | I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3 The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]] Then I changed one of the innermost values: my_list[0][0] = 5 Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]] which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it? |
I searched a lot for static variables in python but could not find a direct answer . Just as java would have a variable defined as static within a class , can the same be done for python? | Is it possible to have static class variables or methods in Python? What syntax is required to do this? |
If I connect to TS over RDP and after that run application which resides on SBS 2003 server (shared app directory), do I need to buy SBS 2003 CAL beside TS CAL? | This is a about Licensing. Questions on licensing are off-topic on Server Fault. If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to. I have a question regarding software licensing. Can the Server Fault community please help with the following: How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y? |
While reading written by Grant Fritchey, I found it difficult to understand the following part: avoid RAID 5 for t-logs because, for every write request, RAID 5 disk arrays incur twice the number of disk I/Os compared to RAID 1 or RAID 10. I know that RAID 5 differentiate from other RAIDs with its parity feature. It means that if some of the drives fails, then it is possible to recover lost data from the other drives. I want to understand why it is not recommended to use RAID 5 for a transaction log file. Explanation in the book was not enough for me to get it. Maybe someone could explain it to me or provide a good article. | We are trying to evaluate the potential performance improvements that could be gained by switching an existing applications .mdf files to a RAID10 LUN vs. the existing RAID5 LUN they are living on right now. The transaction log already lives on a RAID10 LUN. So the question is, if we move data files to RAID10 would the end user see performance improvements in the GUI? or would it be just faster writes to the data files when a checkpoint occurs and the changes get written to the data file but no improvement would be seen at the end user level? |
after try to install lazarus free pascal broken packages E: /var/cache/apt/archives/fp-units-rtl-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/units/i386-linux/rtl/si_c21g.ppu', which is also in package fpc 3.0.0 E: /var/cache/apt/archives/fp-compiler-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/ppc386', which is also in package fpc 3.0.0 E: /var/cache/apt/archives/fp-units-base-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/units/i386-linux/ncurses/ocrt.o', which is also in package fpc 3.0.0 E: /var/cache/apt/archives/fp-units-fcl-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/units/i386-linux/fcl-passrc/paswrite.ppu', which is also in package fpc 3.0.0 E: /var/cache/apt/archives/fp-units-gtk2-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/units/i386-linux/cairo/cairoft.o', which is also in package fpc 3.0.0 E: /var/cache/apt/archives/fpc-source-3.0.0_3.0.0+dfsg-2_all.deb: trying to overwrite '/usr/share/fpcsrc/3.0.0/rtl/android/jvm/java_sys_android.inc', which is also in package fpc-src 3.0.0 E: /var/cache/apt/archives/fp-utils-3.0.0_3.0.0+dfsg-2_i386.deb: trying to overwrite '/usr/lib/fpc/3.0.0/units/i386-linux/utils-lexyacc/lexlib.o', which is also in package fpc 3.0.0 | For example: $ sudo apt-get install curl Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: bsh : Depends: libjline-java but it is not going to be installed groovy : Depends: libjline-java but it is not going to be installed rhino : Depends: libjline-java but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). I get the same or similar errors when I attempt to install clojure1.3, leiningen, and several other packages. When I try the suggestion made in the error message, this is what happens: $ sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required: diffstat linux-headers-3.2.0-26-generic linux-headers-3.2.0-26 dh-apparmor dkms html2text libmail-sendmail-perl libsys-hostname-long-perl Use 'apt-get autoremove' to remove them. The following extra packages will be installed: libjline-java Suggested packages: libjline-java-doc The following NEW packages will be installed: libjline-java 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. 23 not fully installed or removed. Need to get 0 B/72.0 kB of archives. After this operation, 129 kB of additional disk space will be used. Do you want to continue [Y/n]? Y (Reading database ... 226243 files and directories currently installed.) Unpacking libjline-java (from .../libjline-java_1.0-1_all.deb) ... dpkg: error processing /var/cache/apt/archives/libjline-java_1.0-1_all.deb (--unpack): trying to overwrite '/usr/share/java/jline.jar', which is also in package scala 2.9.2-400 Errors were encountered while processing: /var/cache/apt/archives/libjline-java_1.0-1_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1) $ sudo apt-get upgrade Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: bsh : Depends: libjline-java but it is not installed groovy : Depends: libjline-java but it is not installed rhino : Depends: libjline-java but it is not installed E: Unmet dependencies. Try using -f. |
I'm creating a database this way: $db=new PDO('mysql:host='.$db_host.';dbname='.$db_name.';charset=utf8',$db_user,$db_pass,array( PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8")); and at some point I want to insert a string in a table containing strange characters, using prepared statements. for example $title='vélo'; $db->prepare('INSERT into table (title) VALUES(:title)'); $db->execute(array('title' => $title)); This causes me the string to be stored as v&eacute;lo, even though the whole database,table and entries are encoded as utf8_general_ci. 1)Could I avoid this transformation? 2)If not, how could I then do a case-insensitive search in my database? using SELECT * FROM table WHERE title LIKE '%velo%' does not give me any results... | I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur? This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2. |
I'm sorry in advance if here is not the suitable place to ask this question, and people can feel free to vote to close this if that's the case. However, since I'm not sure about this issue, I'll ask it in any way: I was reading Hungerford's Algebra, and my friend working on food science saw the title "Fundamental Theorem of Galois Theory", and asked me what it's about. (Seeing the word "fundamental", he thought it should be a very basic, simple concept.) Then, I said something like "there are structures called groups, fields, and they have some special subsets called subgroup, subfields. In order to understand subfields, mathematicans makes a correspondence between subgroups of some associated group, which is easier to work with and better understood, compared to fields." He said it made some sense, but I'm sure it was a terribly bad explanation. My question is how do people generally deal with this issue? Is this only my problem (which really might be the case), or is this a general problem with pure math people? This issue really annoys me in the sense that, for example, when you consider some person working on food science, psychology, chemistry etc., they're generally able to tell roughly what they're trying to do. But, I'm always having very hard time when I'm asked the same question. I'm a PhD student now, and I plan on spending whole my life with mathematics. But, I'm afraid that, say in my 50 (if I live that much), if someone asks me what I did in my entire 50 years, and I fail to answer, that would be a shameful situation for me, I believe. I tried my best to express my question in a good way, but still I'm sorry if it's not good enough, and don't hesitate to let me know if I should write some parts more clearly/explicitly. | "You do research in mathematics! Can you explain your research to me?" If you're a research mathematician, and you have any contact with people outside of the mathematics community, I'm sure you've been asked this question many times. For years now, I've struggled to find a satisfying answer. I think an ideal answer to this question should: be accessible to someone who hasn't studied math since high school build intrigue and wonder honestly, albeit vaguely reflect your research only require a few sentences (Of course, these guidelines will change depending on the audience and venue. For example, speaking with an engineer over a meal allows more time and technical language than would speaking with a stranger on a bus.) I study the representation theory of algebraic groups and Lie algebras over fields of positive characteristic, so I usually say something along the following lines: I work with two algebraic objects that are closely related called algebraic groups and Lie algebras. These objects can act on spaces (like three-dimensional space) by transforming them in a nice way, and I study these actions. One aspect of my work that is especially challenging is that I use number systems in which a chosen prime number is equal to zero. Honestly, based on my guidelines above, I think this response is poor, but with so much to communicate in such limited terms with such limited time, the task seems nearly impossible. Using my guidelines, how would you describe your own field of research? Or, if my guidelines are too strict, how would you deal with this question? |
I have a x86_64 system. 3.13.0-36-generic #63-Ubuntu SMP x86_64 GNU/Linux. I'm trying to find packages for netperf. apt-get install doesn't find it. I see the package is available here, but not for x86_64: I must be stupid, can someone point how can I install this package? Thanks in advance. | I keep seeing places refer to the "multiverse" repository as a place I can get software, how can I enable this repository? Please specify how to do this graphically and via command line. |
First of all this is not a duplicate question my need is to have 2 precision decimal always e.g. 2 should be converted as 2.00 0 should be converted as 0.00 0.5 should be converted as 0.50 output number has to be decimal Things i had tried decimal val = 0.5000M decimal d = Math.Round(val, 2);//gives 0.5 i need 0.50 NOTE: I am not looking to convert decimal to string as i need to send it as a soap request which accepts decimal value only, so i dont have flexibility to convert it to string. Update below code as answered by Jakub Lortz works fine though it may look complex solution 1 by Jakub Lortz decimal twoPoint00 = new Decimal(200, 0, 0, false, 2); decimal twoPoint0 = new Decimal(20, 0, 0, false, 1); Console.WriteLine(twoPoint00) // prints 2.00 Console.WriteLine(twoPoint0) // prints 2.0 solution 2 by Bogdan he had given very simple solution which will also work decimal val = 0.5000M; string result = string.Format("{0:f2}", val); decimal d; Decimal.TryParse(result, out d); | When displaying the value of a decimal currently with .ToString(), it's accurate to like 15 decimal places, and since I'm using it to represent dollars and cents, I only want the output to be 2 decimal places. Do I use a variation of .ToString() for this? |
my table is overflowing my page horizontally. I need it to stay within my defined margin for the document and still be displayed completely. I already tried the following links, but I did not succeed: • • • \documentclass{article} \usepackage[utf8]{inputenc} \begin{document} \begin{table} \centering \caption{Requisitos Funcionais e Não-Funcionais do Sistema} \label{requisitosfuncionais} \begin{tabular}{|l|l|l|l|} \hline \multicolumn{1}{|c|}{\textbf{Nome}} & \multicolumn{1}{c|}{\textbf{Descrição}} & \multicolumn{1}{c|}{\textbf{Prioridade}} & \multicolumn{1}{c|}{\textbf{Tipo}} \\ \hline Geração Automática~ & \begin{tabular}[c]{@{}l@{}}Capacidade de entregar ao usuário \\avaliações geradas de forma automática\end{tabular} & Essencial & Funcional \\ \hline Cadastro de Questões & \begin{tabular}[c]{@{}l@{}}Capacidade de armazenar questões\\em um banco de dados\end{tabular} & Essencial & Funcional \\ \hline Língua: Português & O Sistema deve ser todo em Português & Importante & Não-Funcional \\ \hline Cadastro de Assuntos & \begin{tabular}[c]{@{}l@{}}Capacidade de armazenar assuntos em\\um banco de dados\end{tabular} & Essencial & Funcional \\ \hline Autenticação & \begin{tabular}[c]{@{}l@{}}Sistema só poderá ser acessado por\\usuários logados\end{tabular} & Essencial & Não-Funcional \\ \hline Editor de Texto & \begin{tabular}[c]{@{}l@{}}Capacidade de inserir questões estilizadas\\e formatas através de um editor de texto\end{tabular} & Desejável & Não-Funcional \\ \hline Geração de Gabaritos & \begin{tabular}[c]{@{}l@{}}Sistema deve entregar ao usuário um~\\gabarito para cada avaliação gerada\end{tabular} & Importante & Funcional \\ \hline Acesso Multiplataforma & \begin{tabular}[c]{@{}l@{}}Sistema deve ser compatível com os\\diversos sistemas e softwares disponíveis\end{tabular} & Desejável & Não-Funcional \\ \hline Integridade do Dados & \begin{tabular}[c]{@{}l@{}}Dados devem ser armazenados com\\precisão e consistência\end{tabular} & Essencial & Não-Funcional \\ \hline Avaliações Editáveis & \begin{tabular}[c]{@{}l@{}}Sistema deve permitir que usuário edite\\a avaliação antes de imprimir\end{tabular} & Desejável & Funcional \\ \hline Controle de Acesso & \begin{tabular}[c]{@{}l@{}}Cada usuário só deverá ter acesso a dados\\pertinentes a ele\end{tabular} & Essencial & Não-Funcional \\ \hline Avaliações diferentes & \begin{tabular}[c]{@{}l@{}}O sistema deverá ser capaz de gerar\\avaliações diferentes a cada vez~\end{tabular} & Importante & Funcional \\ \hline \end{tabular} \end{table} \end{document} | I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met: The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction. What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist? |
During the upgrade, my computer shut down. After starting it I see a black screen with [OK] sentences with finished tasks after them. The last one is: [OK] Started GNOME display Manager. Dispatcher Service...ed database.s.pp link was shut down... Do I need to format my computer? If not, what else can I do? | During my attempt to upgrade my Xubuntu 14.04 installation with sudo apt-get dist-upgrade I made the mistake of interrupting the process by closing my laptop, which caused it to suspend to disk. After re-opening, the monitor remained black, so I was forced to reboot the system. I have since discovered many failures of drivers (wlan0 missing, USB memory stick cannot be mounted, USB mouse not recognised, and maybe more undiscovered problems with hardware). My beginner's attempts to manually repair the single problems could have made it even worse. During the installation of the current distribution I chose to encrypt my whole hard disk. |
What Ubuntu-based distribution can you recommend which has a Rolling release model? I want to have available both Ubuntu specific software (eg. Unity / Virtualbox / Snaps) and newer other software like from Debian Testing. What do you think? I want it to be a Ubuntu/Debian based distro, to be able to install .deb files. | There were so many discussions about an Ubuntu with RR. They were so many pros and contras. At the end ubuntu wont be changed, the 6 month cycle system wont be changed. Thats fine! But because there are so many people who would like to use an ubuntu with RR Im asking myself why isnt there an Ubuntu Derivate with RR. I couldnt found one, there are a loooot of Ubuntu Derivates but no RR. Is it just impossible? I mean Ubuntu = 6 months cycle, so the derivate have to be a 6 month cycle too? Is there no other option? Or are there already some smart guys trying to solve this problem? Thank you! |
My grandfather was a German born in Romania in 1895. I need to get a copy of his birth certificate to prove he was German, as I need to prove he was German to apply for a German passport for my elderly mom. How do I go about getting it or proof of his German heritage? | My husband's family came from Bucharest. Specifically his mother was born in Sibiu. I have been able to piece together names and relations of several grand and great grandparents from word of mouth and some fortunate pictures they had of the cemetery in Sibiu. I cannot however find any records of birth's and death's for any of them. Are there sites or organizations that hold records for Romania? |
The thing I want to input: $$\frac{1}{n+1} + \frac{1}{n+2} + ... + \frac{1}{2n} > \frac{13}{24}, n>1$$ The best I managed so far: But it says it's not true. I can do the first step of the proof and it's true (for n=2). Answer for this problem: my question is not a duplicate, as it's about wolfram alpha not interpreting this correctly. | Proving $\frac{1}{n+1} + \frac{1}{n+2}+\cdots+\frac{1}{2n} > \frac{13}{24}$ for $n>1,n\in\Bbb N$ To solve it I used induction but it is leading me nowhere my attempt was as follows: Lets assume the inequality is true for $n = k$ then we need to prove that it is true for $k+1$ so we need to prove $\frac1{k+2} + \frac1{k+3}+\cdots+\frac1{2(k+1)} > 13/24$ I don't know where to go from here please help. |
Just watched the 'How Big is the Universe?' TV program and it indicated that the universe is believed to be infinite in size. They used an approach involving measuring the internal angles of triangles. Or something like that anyway. But hang on, the Universe has a known starting time and size followed by a finite time expanding at a finite speed. So surely, by definition, it cannot be infinite? I can accept it is honking big but by definition it cannot be infinite. Are they misleading me? | This question is about cosmology and general relativity. I understand the difference between the universe and the observable universe. What I am not really clear about is what is meant when I read that the universe is infinite. Does it have infinite mass or is it dishomogeneous? How can the universe transition from being finite near the big bang and infinite 14 billion years later? Or would an infinite universe not necessarily have a big bang at all? |
I'm getting an error message in my Android application when I call the actionPlaying button in the onPlay method. Here is my code: @Override public void onReceive(Context context, Intent intent) { if(event.getAction() != KeyEvent.ACTION_DOWN) return; switch (event.getKeyCode()) { case KeyEvent.KEYCODE_HEADSETHOOK: case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE: actionPlaying.playandpause(); Toast.makeText(context,"Play",Toast.LENGTH_SHORT).show(); break; case KeyEvent.KEYCODE_MEDIA_NEXT: break; case KeyEvent.KEYCODE_MEDIA_PREVIOUS: break; } } ... MediaSession mediaSession = new MediaSession(context,"tag"); mediaSession.setFlags(MediaSession.FLAG_HANDLES_MEDIA_BUTTONS | MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS); mediaSession.setCallback(callback); PlaybackState state1 = new PlaybackState.Builder() .setActions( PlaybackState.ACTION_PLAY | PlaybackState.ACTION_PLAY_PAUSE | PlaybackState.ACTION_PLAY_FROM_MEDIA_ID | PlaybackState.ACTION_PAUSE | PlaybackState.ACTION_SKIP_TO_NEXT | PlaybackState.ACTION_SKIP_TO_PREVIOUS) .setState(PlaybackState.STATE_PLAYING, 0,1) .build(); mediaSession.setPlaybackState(state1); mediaSession.setActive(true); } MediaSession.Callback callback = new MediaSession.Callback() { @Override public boolean onMediaButtonEvent(@NonNull Intent mediaButtonIntent) { return super.onMediaButtonEvent(mediaButtonIntent); } @Override public void onPlay() { super.onPlay(); actionPlaying.playandpause(); } @Override public void onPause() { super.onPause(); } @Override public void onSkipToNext() { super.onSkipToNext(); actionPlaying.clicknext(); } @Override public void onSkipToPrevious() { super.onSkipToPrevious(); actionPlaying.clickback(); } }; MainActivity class @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_home); IntentFilter filter = new IntentFilter(Intent.ACTION_MEDIA_BUTTON); MyBroadCastRecevier r = new MyBroadCastRecevier(); registerReceiver(r, filter); } This error message is shown when the app is closed Logcat Error Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'void com.rehoboth.myapplication.ActionPlaying.playandpause()' on a null object reference at com.rehoboth.myapplication.MyBroadCastRecevier.onReceive(MyBroadCastRecevier.java:48) at android.app.ActivityThread.handleReceiver(ActivityThread.java:3177) at android.app.ActivityThread.-wrap18(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1653) at android.os.Handler.dispatchMessage(Handler.java:105) at android.os.Looper.loop(Looper.java:156) at android.app.ActivityThread.main(ActivityThread.java:6517) I create Code this for Headset button event but it's not working. | What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely? |
So I have a really stupid problem: I followed this tutorial () and accidentally mapped the "Initiate line" hotkey to mousebutton 1, which means that left clicks are no longer registered and all that happens instaed is that I draw a green coloured line on my desktop that stays until I reboot my pc. I was wondering if there was a way to fix this issue using only terminal, which is pretty much the only application I can use right now. The graphics interface of compizconfig-settings-manager is pretty much completely inaccessible now. Thanks in advance! | I'm using Ubuntu 13.04 (Raring) I've installed CompizConfig Settings Manager (CCSM) and wanted to enable the wobbling window effect. This disabled some other things and suddenly I didn't have window borders any more... Following various instructions I found at Google, I've tried the following steps: Go to CCSM Preferences / Reset to defaults This disabled all plugins and effects (including Unity) so I didn't get any further... executing dconf reset -f /org/compiz and rebooting This brought borders back, but still don't have close/mini/maxi buttons, can't resize or move windows. And the top left entries of the menu bar vanished (Logout, battery, volume...) so I have to shutdown my computer via a terminal... Edit: Following the instructions from the first answer. This brought my menu bar applets back... dpkg-reconfigure didn't seem to work. Result of this command: /var/lib/dpkg/info/compiz.config: 1: /var/lib/dpkg/info/compiz.config: [general]: not found /var/lib/dpkg/info/compiz.config: 2: /var/lib/dpkg/info/compiz.config: backend: not found /var/lib/dpkg/info/compiz.config: 3: /var/lib/dpkg/info/compiz.config: plugin_list_autosort: not found /var/lib/dpkg/info/compiz.config: 5: /var/lib/dpkg/info/compiz.config: [gnome_session]: not found /var/lib/dpkg/info/compiz.config: 6: /var/lib/dpkg/info/compiz.config: backend: not found /var/lib/dpkg/info/compiz.config: 7: /var/lib/dpkg/info/compiz.config: integration: not found /var/lib/dpkg/info/compiz.config: 8: /var/lib/dpkg/info/compiz.config: plugin_list_autosort: not found /var/lib/dpkg/info/compiz.config: 9: /var/lib/dpkg/info/compiz.config: profile: not found /var/lib/dpkg/info/compiz.config: 11: /var/lib/dpkg/info/compiz.config: [general_ubuntu]: not found /var/lib/dpkg/info/compiz.config: 12: /var/lib/dpkg/info/compiz.config: backend: not found /var/lib/dpkg/info/compiz.config: 13: /var/lib/dpkg/info/compiz.config: integration: not found /var/lib/dpkg/info/compiz.config: 14: /var/lib/dpkg/info/compiz.config: plugin_list_autosort: not found /var/lib/dpkg/info/compiz.config: 15: /var/lib/dpkg/info/compiz.config: profile: not found Is there any possibility to reset the settings like they were after installing Ubuntu? Edit 2: Just noticed that the title bar of windows isn't missing; It's just hidden under the menu bar. So the buttons are only hidden, too. Edit 3: PROBLEM SOLVED Started CCSM, went to window management and checked scale windows and move windows... After a re-login everything was fine. |
How do I handle prepositional verbs in an or proposition? Here is an example: if a user needs to be added or removed ? the database The question mark is there as a placeholder. Since you add to and you remove from, writing if a user needs to be added or removed from the database seems a bit awkward, so does if a user needs to be added to or removed from the database. I'm interested both in what is right in formal English and in a less formal setting - could if a user needs to be added to/removed from the database work? Thanks! | Let's say that I have a compound phrase: "... to import or export..." that I want to qualify: "from a given database" The issue is that you would use different preposition depending on the verb: "import into" and "export from". So which single preposition would you use and what is the rule? Perhaps the correct sentence is ".. to import into or export from a given database" meaning that it is incorrect to use a single preposition? Thanks |
For reasons outside the scope of this question, I need to deploy a specific database from my main server to a secondary server; the problem I have is that the secondary server does not exist yet and I need to purchase it. The thing is, how can I measure the CPU, IO and Memory used by this specific database in order to buy a server capable of handling the load of this specific database in the same (or less) time than the current server? Any guidance on this topic is greatly appreciated. | We currently have several shared SQL Server servers and instances in our organization. They are going with a different architecture where business units will get their own SQL Server instances. We have SQL Server 2008R2. In the past, databases were put on servers in a more or less random fashion -- business use and disk space were the main drivers. I've been tasked with coming up with a plan for allocating our 50+ databases across 3 servers (one instance per server). My criteria for divvying them up is as follows: Business critical db's should be spread across the servers. i.e. avoid lumping a bunch of business critical db's all one server. For the remainder of the non-mission critical db's, consider: a. Disk space usage b. I/O usage -- memory, CPU, etc. 1 and 2a are easy for me to figure out. I know how to get data file sizes. My question is with that last bit - 2b. I do not know how relevant this is, what specific stats to look at, or how to get them. Frankly, I'm not 100% sure how to phrase this question! I think I basically want to know is, "How 'busy' is this db -- however you define 'busy'?" Or maybe, "How does this db impact the performance of the server?" I mean, disk space is important -- but it could (in theory) have a ton of rows or binary objects in there that are not written very often, so it has little impact on the performance of the server. I think I would want to know how much impact a db within a date range. Is there a way to get these kind of general stats? I'm not looking for expensive queries, detailed user stats, or query optimization here. I'm aware of the SSMS reports, but they seem to be more real-time. The end goal is to divide up our current databases into evenly balanced buckets, and I would think performance is one way to do that. Thoughts? Wisdom? Any other ideas on how to divvy up the db's? Thanks! Tom |
First of all, yes, I know I'm a moron. Long story short, I overwrote the first few dozen megabytes of a 2 terabyte disk, clobbering the partition table and beginning of an NTFS partition. It's all totally replaceable data, it's just an awful lot, and will be a huge pain in my ass to download over again. Obviously the clobbered data is a lost cause, but I'd like to know if there's any way to partially recover the rest of the data on the old filesystem. I've taken a quick look with the sluethkit and done a bunch of googleling, to no avail. Thanks everyone. | I have a harddisk with two partitions: one for windows and one for data. I've reinstalled windows on the first partition and formatted the data partition with full format (without /Q option) making sure that all my data is backed up. After that I've created the same folder structure (without files inside) on data partition as it was before formatting. I then realized that all my photos were NOT backed up :(((( I've tried several tools to recover my data without any success: Wordershare Photo Recovery Active File Recovery R-Studio PhotoRec from CGSecurity Recuva There are max 50Mb of new data on that partition, so data overwriting is minimal. What is the reason why I'm not able to recover my data with data recovery tools: full format or same folder structure? And... can I get my photos back or they are lost forever? |
I can't play a DVD on vlc, it just won't play. I tried downloading libdvdread4 but that won't help. I tried the solutions on but again it involved downloading libdvdread4. when I try, I get an error saying "libdvdread4 is already the newest version." | My machine can't play encrypted DVDs on a fresh install. How do I add this capability? Another useful bit of information would be what programs are best for playing DVDs, once I'm able to do so. See the . Will I be able to play DVD movies from ? |
There are plenty of examples of differentiable functions $\Bbb R\to\Bbb R$ with derivatives that are not everywhere continuous. However, as stated , it is impossible for the derivative to be nowhere continuous. In general, can anything be said about exactly how "ugly" a derivative can get? | There is a well-known result in elementary analysis due to Darboux which says if $f$ is a differentiable function then $f'$ satisfies the intermediate value property. To my knowledge, not many "highly" discontinuous Darboux functions are known--the only one I am aware of being the Conway base 13 function--and few (none?) of these are derivatives of differentiable functions. In fact they generally cannot be since an application of Baire's theorem gives that the set of continuity points of the derivative is dense $G_\delta$. Is it known how sharp that last result is? Are there known Darboux functions which are derivatives and are discontinuous on "large" sets in some appropriate sense? |
My husband holds a UK business visa and asked me to apply for a visit visa. I have filled in my application and entered my uncle's address under the question of where I plan to stay. I am trying to give the same address for my child, as well, but it keeps asking me the relationship between my uncle and my child. As it isn't an option for direct family, I cannot proceed further. I read previous answers here that mention a GWF number, but I don't understand where to mention it in the online application. Also, what do I put in for the question about how much I plan to spend in the UK? | We are sponsoring a family to visit us in UK as friends from Madagascar for two weeks. They have a 6 year old and a 16 month old. Do the kids need their own visas, and are they the standard visitor visa or a special child visa? Also, when I try and apply on the website I can only apply for one person so how do I apply for all the individuals in the family? I have looked on the Immigration website and can't find the answers I need. |
I am trying to validate a webiste url and using this RegExp for that var websiteregex = /^(?:(ftp|http|https):\/\/)?(?:[\w-]+\.)+[a-z]{3,6}$/; This is working fine for all expect for the domaains of other countries for example example.com.mt.For that it is not working.It is working for example.com.How i can customize the expression for making it work for all types of urls | How can I check if a given string is a valid URL address? My knowledge of regular expressions is basic and doesn't allow me to choose from the hundreds of regular expressions I've already seen on the web. |
Given an alphabet $\Sigma$ (of size at least $2$) let $L$ be the language consisting of words of the form $a^kb^k$ with $k\in \mathbb{N}$ and $a,b\in \Sigma$. Then for any $p\in \mathbb{N}$ pick $a\neq b\in \Sigma$ and we have $a^pb^p\in L$. If we write $a^pb^p=xyz$ with $|y|\geq 1$ and $|xy|\leq p$ then $y=a^i$ for some $i\geq 1$ and $xy^2z=a^{i+p}b^p\notin L$. From we may conclude that $L$ is not regular. Let $L'$ be the language consisting of palindromes: that is strings on $\Sigma$ which are invariant under reversing. Is there a proof (similar to the one above for $L$) that $L'$ is not regular using the pumping lemma? | I'm trying to prove that $L = \{ww^R : w \in \{a,b\}^*\}$ ($w^R$ is the reverse of $w$) is not regular using the pumping lemma. Let $p$ be the pumping length and $s = a^pbba^p$. $x = \epsilon$, $y = a^p$, $z = bba^p \implies s = \epsilon a^p bba^p = a^pbba^p$ 1) Was $s$ properly divided? Let's see: $|xy| \leq p$ $|y| > 0$ (I'm not sure about this since $|y|$ depends on $p$?) If we take $i = 2$, $xyyz = \epsilon a^p a^p bba^p \notin L$, so $L$ is not regular. 2) What about $i = 0$? $xz = \epsilon bba^p \notin L$, so $L$ is not regular. |
Suppose I have a random number generator and I want to check with a Chi Square Test whether its pdf is uniform or no. I can write a script that does that and I will run it several times. To my surprise, I get completely different results each times. Sometimes I will get a p-value of 0.3, sometimes 0.987 and other times 0.003. Which is the number I should take? Should I try to get an average of the p-values I get? How do I decide if this generator passes the test or not? So what I try next is using a random number generator that I already "know" to be uniform and I run the test on that. And I keep getting absolutely varying results. Even if I increase the number of samples, it keeps varying a lot! From what I understad, the probability if seeing a very low p-value when drawing random samples from a uniform distribution should be low, and the probability of seeing a high p-value should be high. But this doesn't seem to happen. How should I interpret the results I get from this test? This is the Python script I am using: import numpy as np from scipy.stats import chisquare bins=256 x = np.random.randint(bins, size=bins*100) h = []; for i in range(bins): h.append(0); for n in range(0, len(x)): h[x[n]] += 1; print(chisquare(h)) and this are the results I get: Power_divergenceResult(statistic=303.19999999999999, pvalue=0.020572599306529871) Power_divergenceResult(statistic=211.06, pvalue=0.97933788750272888) Power_divergenceResult(statistic=289.66000000000003, pvalue=0.066874498546635575) Power_divergenceResult(statistic=275.63999999999999, pvalue=0.17885688588645363) Power_divergenceResult(statistic=257.86000000000001, pvalue=0.43814613213884313) Power_divergenceResult(statistic=217.07999999999998, pvalue=0.95911527563656596) Even more, I did a histogram of the p-values I got and it looks pretty uniform. If I know the samples I have are drawn from a uniform distribution, shouldn't I get most of the times a high p-value? | Recently, I have found in a a statement that p-values should be uniformly distributed. I believe the authors, but cannot understand why it is so. Klammer, A. A., Park, C. Y., and Stafford Noble, W. (2009) . Journal of Proteome Research. 8(4): 2106–2113. |
Is there any reason that one could not revert to a previous OS (e.g. from a disk image) after installing the full release of Windows 10? It might be possible for MS to repartition the disk during installation, or to install a new file system that could not be read by the WinPE or Linux restore media. Has anyone had experience, at least with the preview version, in doing a full restore? This is not exactly what is asked in , Uninstall Windows 10 Tech Preview... the question concerns a full disk restore. | I joined in the and I don't like it. However, this question may also be relevant to those who install the full version of Windows 10. How can I downgrade back to Windows 8/7 from Windows 10 or Windows 10 preview? |
I would like to buy a Helios 44-2 lens, but I need to know if my Nikon D3300 will allow me to take pictures with it since the lens has no pins. Will there be any other problems? | I wanted to get some cheap old lenses to use on my Nikon DX DSLR (D3100). However, Nikon has one of the greatest flange distances of all manufacturers, which means that most lenses I can buy (M42 mount, etc) will not focus to infinity. I saw some adapters with correction lens to allow infinity focus, but also read they worsen picture quality. Has anyone here used this kind of setup? (M42 cheapo old lens + adapter to Nikon with/without infinity focus correction lens) If so, what can I be expecting, quality-wise? I read M42 lenses are not that bad, and I only have DX lenses, so I would not be expecting heavenly performance. Basically, I'd like a nice big tele lens (300mm+) and the ability to focus it to infinity. Example pictures would be awesome, and particularly I'd like to hear some interesting opinions complemented by example photos of the setup I'm talking about — a picture is worth a thousand words. |
The samples in the rendered picture are set to 12, I tried setting them to 20 and it made no difference. I don't understand why, but this is the only object in my scene that has this weird lighting (the actual room itself). | I was following on creating a watch and noticed that when I rendered the watch, some pieces were messed up. I'm new to 3D modeling and I've just learned Blender, I can't explain it well, so here's a picture: Other examples: I don't know if it's a problem with my World texture, the object, or the object's texture/material, so I can't even guess how to fix it. What causes this? Is it possible to fix it? |
We know that the Universe evolved from a very low entropy state in the early universe to very high entropy state of today's universe. What is the quantitative definition of the net entropy of the present universe? How can we measure the net entropy or its change in the universe today? I want some concept and formulas related to that and I'm not talking about the early universe. The question discusses theoretical calculation of the entropy but not experimental measurements of it. An experimentalist's or observers perspective might also be illuminating for me. | What's the entropy of the universe today? How does one go about calculating this? I've heard the statement that black holes account for the bulk of the entropy in the universe today, but don't know why this would be true or the relationship between black holes and entropy. |
I want to show that in a compact metrix space $X$ ,the function $f :X \to X$ such that $d(x,y) \le d(f(x),f(y))$ is surjective! I tried to show that f is continuous and injective but i don't think it really have to... | $K$ is a compact subset of $\Bbb R^n$ and $f:K\rightarrow K $ satisfies : $$\|f(x)-f(y)\|\geq \|x-y\|$$ Show that $f$ is bijective, and that : $$\|f(x)-f(y)\| = \|x-y\| $$ It's easy to show that $f$ is injective. But I can't think of a way to prove surjectivity. |
Let $x,y\in R^d$ and $d:R^d\times R^d \rightarrow R$ a metric on $R^d$ be given. The exponential kernel is defined by: $k(x,x')=e^{−αd(x,x')}$ where $α>0$. The kernel matrix is defined as the Gram matrix of $k$: $K_{ij}=k(x_i,x_j), i,j∈[1…n]$. Is it possible to prove that $K$ is a positive (semi-positive) definite matrix, i.e. $k$ is a positive definite Mercer kernel? | There is the notion of Generalized RBF Kernels, for example in "Towards Optimal Bag-of-Features for Object Categorization and Semantic Video Retrieval" from Jiang (1) or in formula (2.72) in (2). They define: Gen. RBF Kernel: $e^{-pd(x,y)}$, where (1) says d can be any distance function and (2) requires it to be a metric. I now have been wondering for a long time: Is a function defined by $e^{-pd(x,y)}$ where d is a metric always a Mercer's Kernel? I think in (2) it sounds like it, but if it were true, not many people know of it, since they are still looking to prove that $e^{-EMD(x,y)}$ is a kernel, where EMD = Earth Mover's Distance, which is a metric. If its not a Mercer's Kernel - do you know of any counter example? |
There are point-and-shoot cameras that offer large range of angle of view. For example, Nikon P900 with 24mm-2000mm. How such lenses exist only in point-and-shoot and too at a very low price? Why does the same equivalent lenses in SLR cost very high? | This week I've read two news stories about two different camera lenses that can magnify things that are very far away. The first is the , which is a point-and-shoot camera that costs $600, has an 83x optical superzoom lens ("the same field of view as a 2,000mm lens on a full-frame camera"), and lets you see the craters of the moon. The second is the , which weighs 36 pounds, costs $180,000, and can take portraits of people a half mile away. A non-photographer might ask, "Why would somebody spend their life savings on a gigantic telescope of a lens when you could take far away pictures with a handheld camera for 1/300th the price?" Well, I am basically a non-photographer, and I would like to ask that question. What does the big one give you that the little one doesn't provide? I understand that small changes in lenses can make a big difference in size and price, but this seems to be of a different scale entirely. What is going on with the optics of the lenses that makes the small one able to be so small and the big one have to be so...big? I'm trying to get a basic intuition for what makes lenses different, and I realize I don't understand enough about how lenses work to even know how to compare these apples and watermelons. |
I've trying to write code that finds the distances between 3 atoms (code below), where their coordinates are given by the 2D list water_coords, where water_coords[0,:] is the x,y,z coordinates of the first atom, etc. I tried writing the following code where the distance between two atoms would be stored in a 2D array dist (where dist[0][0] is the distance from the 0th atom to the 0th atom, dist[1][0] is the distance from the 0th atom to the first atom, etc.) For some reason whenever I run my code, though, the rows just end up duplicating every loop. I thought it might be a reference / deep copy issue, but using dist[i][j] = copy.deepcopy((x*x + y*y + z*z) ** .5) Didn't change anything. Any help would be really appreciated! | I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3 The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]] Then I changed one of the innermost values: my_list[0][0] = 5 Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]] which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it? |
When using a ComboBox set the AutoCompleteMode to SuggestAppend in the designer, when accessing the init of that form through a background worker, the following exception is thrown: "Current thread must be set to single thread apartment (STA) mode before OLE calls can be made" I know how to fix the problem, but what I am asking is why an STA thread is required to set this property? Note: This is using WinForms, .NET 3.5, C# | Why do Winforms programs have the [STAThread] attribute on the Main() method and what are the consequences of removing it? |
In my references (the library is automatically produced by Mendeley) I have a paper "Abc", which I refer to quite a lot. At one point I need to refer to a specific section in this paper (or a page, it doesn't matter). Is there a way to do that? Something like: "in Abc, section 3.2" or "in Abc, page 15". \documentclass{article} \bibliographystyle{apalike} \usepackage{filecontents} \begin{filecontents}{\library.bib} @book{abc, author = {Alphabet, A.}, year = {1990}, title = {Abc}, publisher = {My Publisher}, } \end{filecontents} \begin{document} I think that the model described in \cite{abc}, chapter 3.2, is awesome. \bibliography{\library.bib} \end{document} | So I'm making this summary of a course where I've only been getting information from one book. Sometimes I want to show what page from the book a statement is taken from but I can't figure out a clean way of doing it. Basically I would like to have something (in function) similar to: "Statement[Book p123]" Do you have any suggestions? |
Is there any section in Tolkien's works which gives the size of an elf? They are mentioned as 'tall' compared to a human (IIRC) so could an average one be six foot six inches? | Are Tolkien Elves taller or shorter than Men? In general fantasy, elves are frequently smaller than humans. But I seem to recall that in Tolkien they aren't. Based on |
If someone says to me, "I would like that" would I answer by saying "I as well or me too? | I'm a bit confused. Is it correct to use "me too" and "I too"? (Also with other pronouns.) For example, if I want to say that Juan gives a present to Ana and I give a present to Ana: Juan gives a present to Ana, [me/I] too. Or if I want to say that Juan gives a present to Ana and Pedro gives a present to Ana: Juan gives a present to Ana, [him/he] too. |
I've noticed for some time now on Meta Stack Overflow that flags I've handled still continue to show up in the page. There was a "not an answer" flag on MSO, which I flagged again as per the instructions, and although the queue is clear, the page still continues to show 1 active flag. Even if I leave the page and come back, it still shows an active flag. Here's a screenshot of the page showing 1 flag, despite nothing showing in the list. This may be happening on other sites as well, where 2k/10k users participate in looking at flagged posts. | This , and as it is a network-wide issue I am bringing it here. Currently, the 10k tools page in Physics (and, I surmise, network-wide) has a toolbar on the top which includes a very visible red counter showing a count of flags. However, upon clicking on it, the counter seldom has anything to do with the actual number of flags available to review. If there are flags for me to review, the counter will typically show more than those, and very often I will be unable to see any flags at all: This has come up before in , but the seems to describe a different bug (the counter dis- and re-appearing over time) which was and marked by Jarrod Dixon ♦. I raised this issue as a in the Physics meta, and : One you have flagged, but so have others - you are seeing the count of others on it, but you can't see it because you have flagged it. The second one also has a couple of flags on it, but one of those is a moderator flag. The count includes the non-moderator flag, but the moderator flag prevents you from seeing the post. So... the count is that of current non-moderator flags (minus yours), the posts don't show up in your list for two different reasons. EDIT: On second thought, this may not be quite as simple. The flag count I see sometimes depends on what tab I'm in. At the moment I see the counter at 4 when I'm in the stats through delete tabs, and it goes down to 3 in the flags tab (with no flags shown, as in the image above). I contend that this is a design flaw: that counter should show the number of posts (or flags) I can and should help out with. There is no reason for me to know that there are posts with moderator flags on them, and it is redundant to show me posts I have already flagged. That counter is prominently visible across all of the 10k tools so that I will go to that page when there's flags I should be handling. Having a nonzero value when there's nothing I can see makes me have to go to the flags page to check whether there's anything, and completely invalidates the purpose of the counter. Also, while I'm at this, can the flags page say something like There are currently no flags for you to review, much like the review queues currently do, when there are no flags there? It is a bit unnerving to have a blank screen there. |
The list of migration options when closing as off-topic should be dynamically generated, based upon how much reputation the user has on the destination site. If they have none, then the only option would be to the child meta. Currently the migration list is a fixed set of Stack sites where the question can be moved. Migration to other sites is possible only by voting to close (or flagging into the review queues). This is OK and it makes sense. However, if the user wants to migrate a question to another site already and has some reputation level (e.g. 300) on the target site (e.g. unix.stackexchange.com), this site should an option on the list. This will guarantee that user has knowledge of the target site's topic and/or scope. The other current issue is that right now the list is static, even if the question wouldn't belong on any of the options. Current situation Anyone who reaches vote to close level can vote to move without any knowledge to a set of sites. Proposed - Not enough reputation on any target sites As you can see, user still may mark question as off-topic, but can not vote to move. Also important thing is . And - reputation requirements reached on two sites The per site meta should be always there, but if the question is technically specific, again, can end up in the wrong place. | With all the new sites up and running it gets more and more difficult for users to really know the scope of a site and thus a lot of questions a migrated to places where they are (probably even more) off-topic, see e.g. . So I request the opposite of : Allow migration if you have enough rep on both the source and the target site (the target reputation required could be a bit lower, say 5001) That way questions could only be migrated by users familiar with the scope of both sites who can really estimate where the question is better. Maybe those who don't have the rep on the target site could still be able to cast a flagging-only-but-not-counting-as-vote vote... 1) Courtesy of |
Let $R$ be a finite ring (that does not necessarily contain the identity) such that more than three fourth of its elements are idempotents. Then show that $R$ must be commutative. If $R$ is a ring with 1 then this case I have proved, but without assuming the existence of it how can it be shown? | It is a well-known result that if a ring $R$ satisfies $a^2=a$ for each $a\in R$, then $R$ must be commutative. See for proof. I am wondering whether the same result holds for finite rings if we only assume sufficiently many (but not necessarily all) elements of the ring are idempotents. Recall that an element $a\in R$ is called idempotent if $a^2=a$. For example, suppose $R$ is a finite ring in which at least $80$% elements are idempotents. Can we conclude that $R$ is commutative? More generally, Does there exist an absolute constant $0<k<1$, such that whenever a finite ring $R$ satisfies $$\frac{\textrm{Number of idempotents}}{|R|}\ge k$$ then $R$ is commutative. Motivation: We know that if every element of a group $G$ satisfies $a^2=1$, then $G$ must be abelian. This is a relatively easy exercise. However, it turns out that we only need 75% percent of elements to satisfy $a^2=1$ in order force $G$ to be abelian. See For reference, $a\in G$ is called involution if $a^2=1$. |
what is invertible elements of polynomial ring $k[x_1,...,x_n]$ ? for case $n=1$ we have $k[x_1]$ and $$ p(x)=a_{0}+a_{1} x+\ldots a_{n} x^{n} $$ then $p(x)$ is invertible element such that $a_{0}$ is a unit in $R,$ and the remaining coefficients $a_{1}, \ldots, a_{n}$ are nilpotent elements. ( $k$ is a field) | I am trying to prove a result, for which I have got one part, but I am not able to get the converse part. Theorem. Let $R$ be a commutative ring with $1$. Then $f(X)=a_{0}+a_{1}X+a_{2}X^{2} + \cdots + a_{n}X^{n}$ is a unit in $R[X]$ if and only if $a_{0}$ is a unit in $R$ and $a_{1},a_{2},\dots,a_{n}$ are all nilpotent in $R$. Proof. Suppose $f(X)=a_{0}+a_{1}X+\cdots +a_{n}X^{n}$ is such that $a_{0}$ is a unit in $R$ and $a_{1},a_{2}, \dots,a_{r}$ are all nilpotent in $R$. Since $R$ is commutative, we get that $a_{1}X,a_{2}X^{2},\cdots,a_{n}X^{n}$ are all nilpotent and hence also their sum is nilpotent. Let $z = \sum a_{i}X^{i}$ then $a_{0}^{-1}z$ is nilpotent and so $1+a_{0}^{-1}z$ is a unit. Thus $f(X)=a_{0}+z=a_{0} \cdot (1+a_{0}^{-1}z)$ is a unit since product of two units in $R[X]$ is a unit. I have not been able to get the converse part and would like to see the proof for the converse part. |
I frequently use simple and larger parenthesis in math mode, like what is shown in the MWE below: \documentclass[11pt,letterpaper,twoside]{book} \usepackage{lmodern} \usepackage{amsmath} \usepackage{mathtools} \newcommand*{\bigs}[1]{\vcenter{\hbox{\scalebox{1.25}{#1}}}} \begin{document} Blabla bla bla blabla : \begin{equation} \Big( c \, \bigs( \big( (1 + (x - y^2)(a + b) \big) \bigs) \Big) = \tfrac{3}{4}. \end{equation} \end{document} I usually don't use the \left \right variants, since I find them too big, and also for other reasons that aren't relevant here. The \big( \big) commands give a nice output when the document is written in 12pt size. The difference with simple () is clear. But then, If I reduce the font to 11pt, the difference becomes very small, almost negligible. Why is that? To solve this, I defined a small macro to give something between the simple parenthesis and the \Big version. But I'm now wondering why I have to do this and if this a proper way of doing things in LaTeX. | This question led to a new package: While writing down my Combinatorics exercises I found that the binomial coefficient's delimiters weren't displayed as indicated inside the amsmath documentation. By subsequent trials and errors I was able to reduce the volume of my document to this simpler and fully compilable MWE: \documentclass[11pt]{article} % \usepackage{amsmath} % \makeatletter % \usepackage{lmodern} \usepackage{lipsum} % \makeatother % \begin{document} % \lipsum[1] \begin{equation} 2^k-\binom{k}{1}2^{k-1}+\binom{k}{2}2^{k-2} \end{equation} \lipsum[1] % \end{document} Which gives (using TeXworks 0.44 on MikTeX 2.9.4521 updated 09/10/13) this un-expected result: While the amsmath doc shows that with the loaded packages inside the MWE the result would actually be like this: From here we can see that the delimiters on the first example are a little bit stretched vertically as they surpass the arguments inside the binom. coeff. The more strange event is that when I comment the line \usepackage{lmodern} the result on delimiter's shape in my example looks exactly as the amsmath doc: \documentclass[11pt]{article} % \usepackage{amsmath} % \makeatletter % %\usepackage{lmodern} \usepackage{lipsum} % \makeatother % \begin{document} % \lipsum[1] \begin{equation} 2^k-\binom{k}{1}2^{k-1}+\binom{k}{2}2^{k-2} \end{equation} \lipsum[1] % \end{document} Output: From here I deduce that the problem lies inside lmodern, but I'd like to keep using this package and fix this wierd "issue" with the math mode. Is there some clue that I've missed or this is in fact an update-process bug infecting amsmath's delimiter control? |
I have Xubuntu 14.04 and I cannot access recovery mode via holding down the SHIFT key. I read almost everywhere that this is how you do it. Does that work for Xubuntu as well or just Ubuntu? The reason this is needed is because I somehow lost sudo on my user account and cant access any root commands. | I read here at that holding Shift during boot can bring up the GRUB menu. However I try holding one or the other Shift keys, tapping, tapping then holding, nothing works. Am I missing something? How does one access the GRUB menu during boot time? No dual boot here, just standard Lubuntu 14.04 install. |
I recently reached 2000 reputation points, which allowed me to see pending edits and approve/refuse them on the Stack Overflow desktop site. But this feature (accessed by clicking the brown number on the top-right hand of the website) seems to be missing from the mobile application, and especially the iPhone app. I spend lots of time on this app, but making a complete question with code and fiddle is a somewhere between hard and impossible on a mobile. However checking pending edits is something technically easy to handle on such a device, but I can't find it. Did I miss anything? | I enjoy reviewing on SO, is it currently possible to review on the iOS app? If not, is it planned to be implemented? |
I am reading Facts From Figures by MJ Moroney. In one part of the textbook (chapter 10, pages 136-137) he writes of samples taken from a population with a normal distribution, that their "standard deviation decreases as the square root of n, the number of items in the sample". He gives a formula where "the standard deviation for the distribution of the individual items" is divided by the square root of the number in the sample to give "the standard deviation for the averages of samples of n items". His example is a population of men with an average weight of 140 pounds with a standard deviation of 20 pounds, and he calculates that the standard deviation of the average weight of a group of four men at a time would be 10 pounds, and for a group of one hundred men it would be two pounds. But later in the book (chapter 13, pages 225-227), he writes that the expected value of the variance in a sample of n items is obtained from the population variance by multiplying the population variance by ((n-1)/n). (The Bessel correction.) I am aware that variance is the square of standard deviation, but after doing some simple algebra to convert the first equation described above to deal with variance rather than standard deviation, then for a sample size of 100 the conversion factor in the first equation is 100, but in the second equation the conversion factor is about 1. A considerable difference. Please can someone explain my misunderstanding. Surely the standard deviation of a population describes the standard deviation of the individuals within that population. | I'm struggling to understand the difference between the standard error and the standard deviation. How are they different and why do you need to measure the standard error? |
In my bibliography, I want to include report numbers of technical reports in teletype font. These report numbers typically consist of several blocks of letters and numbers connected by hyphens, like INSTITUTE-YEAR-MM-NUMBER. It is fine for the report numbers to have a line break after any of the hyphens. So far, I have been using \nolinkurl without much thought, and it provides good results. Now, I need to include report numbers that have one block separated from the rest by a space. This space is suppressed by \nolinkurl. to the same issue, the accepted answer is to use \texttt instead. However, with \texttt, the automatic line breaks don't work. Minimal example: \documentclass[12pt]{article} \PassOptionsToPackage{hyphens}{url} \usepackage[breaklinks]{hyperref} \usepackage{showframe} \newcommand{\thereport}{REPORT-19-12-001 SPECIAL} \begin{document} This is a long line and at the end of the line there should be \texttt{\thereport} referenced. This is a long line and at the end of the line there should be \nolinkurl{\thereport} referenced. \end{document} How can I have report numbers with hyphens and spaces in teletype font with automatic line breaks? | The following code \documentclass{article} \usepackage{filecontents} \begin{filecontents*}{"a b c.tex"} one two \end{filecontents*} \usepackage{listings} \usepackage{hyperref} \begin{document} \lstinputlisting[caption={\url{a b c.tex}}]{"a b c.tex"} \end{document} produces a hyperlink with suppressed spaces given in the path. How to prevent \url from removing the spaces in a path? |
I'm trying to install ROS Kinetic on Ubuntu Xenial and this is the error: E: Malformed entry 1 in list file /etc/apt/sources.list.d/ros.latest.list (Component) E: The list of sources could not be read. What do i add to this line on the file? The only entry from sources.list.d/ros.latest.list: deb http://packages.ros.org/ros/ubuntu xenialmain | I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that. I just tried to upload a screen shot but since I'm new it won't allow me to. I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following: COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse) E: The list of sources could not be read., E: The package list of status file could not be parsed or opened. How do I report bugs? What can be done about this. I have searched and everything everyone says to do leads me back to the same line error message. So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software. |
I am having form which takes url as input..I want to validate it using javascript and regular expression.. it should accept www.google.com google.com http://google.com Please suggest me a regular expression and total code if possible for validation of url... i tried lotta url given on many forums..but couldn't get appropriate answer.. thanks in advance | How can I check if a given string is a valid URL address? My knowledge of regular expressions is basic and doesn't allow me to choose from the hundreds of regular expressions I've already seen on the web. |
is it possible to prove that planets (and/or stars) are always round (elliptical if you consider the spin)? Is there a set of equation that demonstrate that fluids (after all, molten rocks "floating" in outer space is that...) tend to form spheres? Maybe theres a way to prove that they can't exist (in a stable condition) in another shape? | Is it possible to use the Lagrangian formalism involving physical terms to answer the question of why all planets are approximately spherical? Let's assume that a planet is 'born' when lots of particles of uniform density are piled together, and constrained only by the Newtonian gravity of the $N$ particles with no external gravity. My question is: Is it possible to use the variational calculus starting from this situation to prove that planets should be spherical? |
I am a US citizen and I am flying to Germany on September 6 2017. My passport expires on March 13 2018 which is not beyond the 6 month period by 7 days. However I keep reading about 6 months validity after my departure date. Is this my departure date coming back home. I leave Germany on September 22 2017. This would leave me 9 days short of the 6 month rule if this is interpreted by departure from Germany. Can someone clarify? | in order to visit. According to , Germany is not among them, but says "U.S. citizens traveling on passports that expire in fewer than six months have increasingly been denied airline boarding or been detained upon arrival in certain foreign destinations, including popular European travel destinations in the Schengen area." echoes that. The State Department's says "Some Schengen countries assume all travelers will stay the full three months allowed for visa-free visitors, meaning you may not be admitted unless your passport is valid for at least six months, regardless of the duration of your stay. This requirement may also apply if you are transiting a Schengen airport for several hours en route to a non-Schengen destination." Is Germany one of those countries? Assume a US traveler planning to go to Germany for a few days with a passport that will be valid for more than three but less than six months after the return flight, with the departure flight too soon to go through the routine renewal process and be confident that a new passport would arrive prior to departure. Can the traveler wait until after the trip to do the renewal? The from the US State Department suggests the traveler can wait, but even that page is inconsistent about the number of blank pages required and the Embassy Messages link produces a 404 error, so the page is of questionable reliability. |
Because if $T(v) = x$ then $T(x) = x$ so it must be the identity transformation ($T:V \to V)$. Right? | Prove that a linear transformation $P \colon V \to V$ of a finite dimensional vector space satisfies $P^2 = P$ if and only if there exists a basis with respect to which $P$ can be written as a block matrix $$P = \begin{bmatrix} I & 0 \\ 0 & 0 \end{bmatrix}.$$ Hence determine the minimal and characteristic polynomials of $P$. I don't know what to do with this problem at all, so some help would be great, Thanks. |
This has been troubling me for days, I have a table with auto-increment, what I want is that the value of the increment value will be inserted in the same row. The problem is that when concurrent users are accessing the query, it will not copy the correct value. Below is my table: CREATE TABLE tblTransactions ( dctransno INT IDENTITY PRIMARY KEY, vcDescription VARCHAR, dcTransNoCopy INT NULL, user VARCHAR ) and my query: BEGIN TRAN INSERT INTO tblTransactions (dctransno, user) VALUES (@vcDescription, @user); SET @identity = @@IDENTITY -- get the identity UPDATE tblTransactions SET dcTransNoCopy = @identity WHERE dcTransNo = @identity AND user = @user; -- insert COMMIT TRAN What I want to achieve is that I can have a grouped transaction like below example. The problem is that my above query doesn't take ownership. Assuming userA and userB are simultaneously using the system: dcTransNo Description dcTransNoCopy User 1 Transaction1 1 userA 2 Transaction2 1 userA 3 Transaction3 1 userA 4 Transaction1 3 userB ---> not correct, ClonetransNo value for userB should be 4 not 3. Please help, thanks in advance. | What is the best way to get IDENTITY of inserted row? I know about @@IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY but don't understand the pros and cons attached to each. Can someone please explain the differences and when I should be using each? |
I read that the puzzle ring has a chance to drop legenderies and I was wondering if these would include torment only legenderies if playing on torment. | Patch 2.0.1 introduced a lot of significant changes to the loot system in the game. One of the significant ones was the revamp to the , which now has a new effect: Summon a treasure goblin who picks up normal-quality items for you. After picking up 12–16 items, he drops a rare item with a chance for a legendary. What is the cooldown on the goblin item drop? Does the effect stack if you have one on your character and another on your follower (i.e. two goblins)? Is the drop chance for the rare/legendary affected by increased Magic Find? If so, approximately how much? Is there a cap on them max item level of the dropped item? (While < lvl 60, at lvl 60, and when the level cap is raised in the expansion.) Does the item counter reset when you leave the game, change acts, or die? |
I got a logo in blender and im trying to rotate it 360 degrees. But when i rotated it i realized it isnt centered. I found out that the logo got some invisible edge or something, because when i do "Origin to Geometry" it still isnt in the middle. (Sry for my bad english + second project in blender) | How can I change the local origin of an object, without changing the object location in the world space. This is the object located at position (0,0,0) in the world space This is the same object located at position (0,1,0) in the world space, but with its local origin offset so that the object is in the same place Is there a way to do this in a single step? |
I'm in the process of working on technical documentation and the phrase "currently-installed" came up. The context of the orginal sentesnece is as follows: "You are not licensed to use the currently-installed product." Normally I see this written as "currently installed" but I was told the other way is correct because it is a compound adjective. Which form is correct? | Should I hyphenate the term 'well organised'? The context, if it matters, is the following sentence: For this role you should be well organised and analytical with some research ability. (I see there are other question here about hyphenation; do point me to one if this falls under a general rule, I just couldn't see it.) |
I have been asked to compress an image that will be used for mass email, the image is currently 628 KB and needs to be 50 KB maximum, I have been advised to use PNG files. I have also been asked to do this using Photoshop, paint.net and GIMP 2. Any advice on all three of these software's would be much appreciated Thanks | I would like to save files in Photoshop but keep them as small as possible. I use Save for Web (and Devices) and save as a JPEG. Here are the settings I used: I really do not want to lower the quality settings because I use text and sometimes I see artifacts if the setting is too low. This produces file sizes of several hundred kilobytes depending on size of image. While this isn't a huge issue these images are used for the web and smaller is better. What are techniques without reducing quality to reduce the file size? Update: To add some more information here: Many of the images I use and create get sent via email. This severally limits what I can do with placing of text using HTML and CSS over the image. Also I use a variety of fonts. Some I could use for the web using CSS's @font-face but you can run into large file sizes and in some cases you cannot upload the font to the web legally. I could use a service like but again many fonts I use are not available with Typekit. Here is an example image: |
Say we want to prove that $$ \left(1 + \frac{x}{n} + o(1/n) \right)^{1/n} \xrightarrow{n \to \infty} e^x \,\,\text{ for fixed }x \geq 0.$$ The case for $$ \left(1 + \frac{x}{n} \right)^{1/n} \to e^x $$ can use monotone convergence theorem, because the columns of the below array are non-decreasing. But if we put the $o(1/n)$ in there, we don't know anymore. $$\begin{matrix} 1 & x & 0 && \dotsb \\ 1 & x & \frac{2 \cdot 1}{2^2}\frac{x^2}{2!} & 0 & \dotsb \\ 1 & x & \frac{3 \cdot 2}{3^2}\frac{x^2}{2!} & \frac{3 \cdot 2 \cdot 1}{3^3}\frac{x^3}{3!} & \dotsb \\ 1 & x & \frac{4 \cdot 3}{4^2}\frac{x^2}{2!} & \frac{4 \cdot 3 \cdot 2}{4^3}\frac{x^3}{3!} & \dotsb \end{matrix}$$ When we include the $o(1/n)$, and we don't know whether $o(1/n)$ is monotone or not, would the usual way be to prove convergence first, by taking a bound for $no(1/n)$, then use dominated convergence theorem, using that it's dominated by $e^{x + \text{bound for }n(o(1/n))}$? Or is there a smoother, more generalizable path? Maybe some clever use of Taylor expansion or something? | We are dealing with $z \in \mathbb{C}$. I know that $$ \left(1+ \frac{z}{n} \right)^n \to e^{z} $$ as $n \to \infty$. So intuitively if $z_n \to z$ then we should have $$ \left(1+ \frac{z_n}{n} \right)^n \to e^{z}. $$ If $z_n \in \mathbb{R}$ I would be happy writing $$ \exp \left(n \log\left(1+ \frac{z_n}{n} \right) \right) = \exp \left(z_n \frac{\log\left(1+ \frac{z_n}{n} \right)-\log(1+0)}{\frac{z_n}{n}-0} \right) \to \exp(z \cdot 1) $$ where here we are using the definition of derivative. But if $z \in \mathbb{C}$ the logarithm is multivalued and I'm not sure that the same calculation is allowed. Is there a different way to show this for complex $z$? |
Its been 7 months since i created my github account. However Google still hasn't indexed my github page. Does anyone know what to do ? | This is a general, community wiki question and answer pair intended to address any questions concerning the reasons a site or specific site contents do not appear in search engine results. If your question was closed as a duplicate of this question and you feel that the information provided here does not provide a sufficient answer, please open a discussion on . My site (or specific pages on my site) is not appearing in search engine results. Why isn't my content indexed and what can I do about it? |
I have a C-business-visitor visa to the UK (multiple entry visa), that I used to represent my NGO in a conference on November. My visa is still valid. Can I use it again to enter to the UK to present again my NGO and plan for a training in citizen journalism for young girls in London? I have a stamp on my visa of the date I entered the UK in. If yes, what do I have to provide at the airport? | I got a business visitor visa, sponsored by a company, for a 4-5 day visit. The visa was provided for a period of 6 months, with multiple entry possible. First, what should I carry with me when entering the UK (at LHR)? Will they just take a look at my visa and let me in, or will I have an interview or something? (I haven't seen indication that I should carry documents or anything with me, but I thought I'd ask). Second, if I want to re-enter the UK in a month or two (not for a business purpose), can I do that on the same visa, since it's multiple entry? Or is the second entry different than the first (i.e. if the first doesn't have an interview, they'll have an interview on the second entry?) |
I could use System.getenv(String name) to get the environment variable, I would ask how to set environment variable with java? I didn't find such method defined in the System class | How do I set environment variables from Java? I see that I can do this for subprocesses using . I have several subprocesses to start, though, so I'd rather modify the current process's environment and let the subprocesses inherit it. There's a System.getenv(String) for getting a single environment variable. I can also get a Map of the complete set of environment variables with System.getenv(). But, calling put() on that Map throws an UnsupportedOperationException -- apparently they mean for the environment to be read only. And, there's no System.setenv(). So, is there any way to set environment variables in the currently running process? If so, how? If not, what's the rationale? (Is it because this is Java and therefore I shouldn't be doing evil nonportable obsolete things like touching my environment?) And if not, any good suggestions for managing the environment variable changes that I'm going to need to be feeding to several subprocesses? |
Why is it there is no “favourites” choice here? I know we can filter for a specific tag in a number of ways. But why not offer to just show all favourite tags? | There is some way in the SO site to list only the questions from my favorites tags? I can access the list of all questions here , and also I can access the list of all questions from one specific tag, i.e. from JS tag in here ., but there is a way to list all the questions from all my favorite tags? If it's not, it's possible to implement this? |
I have come across some confusion making my system accept multiple languages. Prior to setting up my database, I did some research as to which collation was best to use to support as many languages as possible. I was advised utf8_unicode_ci was the most viable encoding. The confusion arises where, although it seems my system can decode any language, phpmyadmin cannot: Translation: English: 'hello' Chinese: '你好' Encoding: System: '你好' Phpmyadmin: 'ä½ å¥½' <------ should read: '你好' How can I have phpmyadmin display these characters correctly? | I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur? This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2. |
I never used the fact the $X$ is compact in my proof below. Which makes me worry if my proof is complete. Let $X$ and $Y$ be metric spaces, $X$ compact, and $T: X \to Y$ bijective and continuous. To show that $T^{-1}$ is continuous, we will proceed by contradiction. That is, suppose that $T^{-1}$ is discontinuous. Since $T$ is bijective, then every element $y \in Y$ is uniquely determined by an element $x \in X$, \emph{viz.}, $Tx = y$ or equivalently $x = T^{-1}y$. By continuity of $T$, if $(x_n)$ is a convergent sequence in $X$ with limit point $x_0 \in X$, then $Tx_n = y_n \to Tx_0 = y_0$. However, this would imply that if $y_n \to y_0$, then $T^{-1}y_n = x_n \to T^{-1}y_0$. A contradiction, since $T^{-1}$ was assumed to be discontinuous. | Let $X$ and $Y$ be metric spaces, $X$ compact, and $T:X \to Y$ bijective and continuous. Show that $T$ is a homeomorphism. My attempt: We need only show that $T^{-1}$ is continuous. Let $M \subset Y$ be closed. Then, from the surjectiveness of $T$, there exists a $A \subset X$ such that $T(A)=M$. Since $M$ is closed, by the continuity of $T$, we must have that $A$ is closed. Now $$T^{-1}(T(A))=T^{-1}(M)$$ i.e, $A=T^{-1}(M)$. Since $A$ and $M$ are closed, we must have that $T^{-1}$ is continuous. My problem with this, however, is that I am not using the fact that $X$ is compact anywhere in the proof. Is there perhaps another way that I can show this, using the compactness of $X$? Any hints will be appreciated. |
Which one is correct? He is not one of those people who make/makes you angry Does "make" refer to "one"? Is there a possibility that "make" refers to "people"? Can it be something relative? | One of the things that makes him great is he brings it every night. I'm pretty sure it should be that make him in the plural, because one of the things is referring to a lot of things and a lot of things should take a plural verb. But I always hear native speakers in America say it in the singular, so with an s. Another example: This is one of the responsibilities that comes with greatness and he understands that. Native speakers always use the verb in the singular (here, comes) even though [I believe] it is grammatically incorrect to use the singular form of the verb there. |
I am very new to Linux. I have been using Linux for only two days now and I am really impressed by Ubuntu. But I am facing a major problem. My PC is a Lenovo 3000 y500. My GPU is an Intel 945GM (integrated graphics) and I don't have any drivers for it because I can't find them. Someone please help me, I really can't wait to play my favorite games anymore. When I run a game I get this error: Could not find required OpenGL entry point 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated. When I type lspci -k | grep -EA2 'VGA|3D' I get the following result: 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) Subsystem: Lenovo Device 3801 Kernel driver in use: i915 | I am not able to play "Half-Life-2" on Steam + Ubuntu 14.04 . Error shown in message box on screen: Could not find required OpenGL entry pint 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated. I have a Dell Inspiron Laptop. My OS is Ubuntu 14.04 and my graphics card is AMD Radeon HD 8600M. I have installed AMD properietry Driver. The partial output of "glxinfo" is as follows: name of display: :0 libGL: screen 0 does not appear to be DRI3 capable libGL: pci id for fd 4: 8086:0a16, driver i965 libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/i965_dri.so libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/i965_dri.so libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL error: failed to load driver: i965 libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/swrast_dri.so libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/swrast_dri.so libGL: driver does not expose __driDriverGetExtensions_swrast(): /usr/lib/i386- linux-gnu/dri/swrast_dri.so: undefined symbol: __driDriverGetExtensions_swrast libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL error: failed to load driver: swrast display: :0 screen: 0 direct rendering: No (If you want to find out why, try setting LIBGL_DEBUG=verbose) |
I am not able to prove this, could any one help me? $G$ be a finite group, $G$ has exactly one proper subgroup. We need to prove that $G$ is cyclic and $|G|=p^2$ where $p$ is prime. Thank you. | How to find all groups that have exactly 3 subgroups? Any group must have identity and itself as subgroups, so we just need to find all the groups that only have one proper subgroup. I think that for a prime $p$ the group $\mathbb Z/p^2\mathbb Z$ has only one proper subgroup (for example, $\mathbb Z/4\mathbb Z$, $\mathbb Z/9\mathbb Z$). Are there any other possibilities? |
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 1,692 B of archives. After this operation, 153 kB of additional disk space will be used. Do you want to continue? [Y/n] Yes, I do want to continue......how do I confirm this? What is the command please? New to Linux. Thank you. | I am new to Ubuntu and some little thing start to bug me. Such as when trying to install a program, Ubuntu asks, Do you want to continue[Y/n]? What is bugging me is why the letter "Y" is upper case and "n" is lower case. Do they have any significant reason why one is upper and the latter is lower? Whatever case I enter it doesn't change the outcome: it either continues or not. Are they trying to notify us that we can enter both and it won't change anything? |
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