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In general, let us have a light emitting point A and two light absorbing points B and C, such that the three points fall on a straight line and B is somewhere between A and C. For simplicity, let us consider all photons emitting from A to travel along this same line in the direction of the points B and C. Also, let the distance from A to B be AB and the distance from A to C be AC. For the photon, special relativity states that there should be maximum space contraction along it's direction of motion. That means that, for the photon, A, B and C are all at the same point in space. This results in the photon effectively "reaching" B and C at the same time. How then does the photon "decide" that it must be absorbed by point B and not C, so as to be consistent with what an outside observer would see (point B "casting a shadow" on point C)? | Disclaimer, not a physicist. When I look at the sky I can see the star Rho Cassiopeiae. In my frame of reference, the photon hitting my retina has traveled for 4000 years and 3.78x10^16 km. In the photon's frame of reference, there's no time elapsed and my retina and the surface of the star are at the same place (no distance traveled). Is that a correct understanding of time dilatation and space compression at relativistic speed? |
How did Harry's watch work in Hogwarts as magic is supposed to render Muggle inventions like electricity and batteries incapable of normal functioning? | Classes and lessons at Hogwarts are presumably scheduled at fixed times of day. The first class might start, for example at nine in the morning. To be on time for one's lessons, it is therefore crucial to know the current time but we know that electric watches of course do not work at Hogwarts because of all the magical interference. Are there magic watches? Is there maybe a spell to tell the time? How do people at Hogwarts usually tell the time? |
I wish some advise. We have a quote from a VAT Registered building company for work on an extension, this quote for simplicity was 50k GBP. At the end of the list of items on the quotethey will complete (doors, plastering, windows electric) they give the 50 k GBP subtotal. After the above line on the quote they say this verbatim “20% all costs are plus VAT at standard rate”. On receiving this quote, I found this very confusing as I did not understand what the word costs related, to the items or the total. I verbally queried if the amount 50k included VAT or not, I understood the answer to be no it was 50 k including the VAT. We start the work, then first bill includes a agreed percentage let’s say 40% of the work. The expected amount was 20k but instead I get a bill for 20k plus VAT I.e 24k. What are your thoughts? Stupid me or misleading? | If I receive a quote for work from a tradesman, and this quote is supplied as a document (PDF) which does not mention VAT as being either includes or excluded, can the tradesman later say that it didn't include VAT and demand I pay 20% more than the amount stated on the quote? |
I have a JSP page where I have put a JS code for confirm() method. I am calling this from the form "onsubmit". The dialog box has 2 buttons "OK' and 'cancel'. On clicking "OK" the form should be submitted which is happening but on click of 'cancel' button I need to redirect the page to some other page. Below is the JS code. function showDialog() { if(confirm("Press OK to confirm")) { console.log("Clicked OK, confirmation.");} else { console.log("Clicked Cancel, confirmation."); } Below is the form tag where I am calling JS function: <form:form name="login" id="login" action="<%=loginPass%>" method="POST" autocomplete="off" onsubmit= "showDialog()"> | How can I redirect the user from one page to another using jQuery or pure JavaScript? |
<html> <head> <style> html,body,#root,.app-container { height:100%; } .navBar { height:50px; } </style> </head> <body> <div id="root"> <div className="navBar"> </div> <div className="app-container"> </div> </div> </body> </html> Despite root is having 100%, scroll is coming initially when you visit to page first time. I have tried by making root height as 100% and app-container height to calc(100%-50px) In this case scroll is still appearing root height as 100% and app-container height to 96% In this case scroll is appearing and app-container is not taking entire height of page i.e., it is not taking height till bottom which is not correct root height as 96% and app-container height to 100% in this case scroll is disappearing but app-container is not taking entire height of page i.e., it is not taking height till bottom which is not correct please let me know how to remove unwanted scroll and app-container to take page height till bottom correctly | I am working on a web application where I want the content to fill the height of the entire screen. The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom. I have a header div and a content div. At the moment I am using a table for the layout like so: CSS and HTML #page { height: 100%; width: 100% } #tdcontent { height: 100%; } #content { overflow: auto; /* or overflow: hidden; */ } <table id="page"> <tr> <td id="tdheader"> <div id="header">...</div> </td> </tr> <tr> <td id="tdcontent"> <div id="content">...</div> </td> </tr> </table> The entire height of the page is filled, and no scrolling is required. For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work. Is there a way to achieve the same effect without using the table? Update: Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%. Update 2: For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works. |
I was given that $S=1+2r+3r^2+\cdots = \frac{1}{(1-r)^2}$ was an identity from my students, and I tried to prove directly using geometric series. I got stuck and looked around online only to be told that taking the derivative of the series that converges to $\frac{1}{1-r}$. I liked that proof because it was simple and easy, but unfortunately my student is in Alg II so I cannot explain her with derivatives. My idea was to expand $S$ as $$(1+r+r^2+r^3+\cdots) +(r+r^2+r^3+\cdots)+(r^2+r^3+\cdots)+\cdots$$ but I get confused whether I should rewrite this as $$(1+r+r^2+r^3+\cdots) +r(1+r+r^2+\cdots)+r^2(1+r+\cdots)+\cdots$$ or $$(1+r+r^2+r^3+\cdots) +((-1)+1+r+r^2+\cdots)+((-1-r)+1+r+\cdots)+\cdots$$ I was able to get the ID using the first way, but I am not sure if the step I took was valid due to some stuff I vaguely remember about manipulating an infinite series like that was not always allowed. And on the second way I simply did not know where to go from there. Can I have some help ? It would also be helpful to know the criteria of when I can manipulate the order of how to add the series. | How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method. In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$ |
I thought I knew that we use differentials just because they made calculus intuitive and there was math rigor behind all of these. But when I saw this problem came out. For example, deriving implicitly: $$ x^2+y^2 = 5 $$ we get $$ 2x\mathrm{d}x +2y\mathrm{d}y = 0 $$ $$ 2xdx+2y\frac{dy}{dx}dx=0 $$ and then to find the slope of the graph we solve for dy/dx $$ \frac{dy}{dx}=-\frac{x}{y} $$ Does't that imply that $dx \neq 0$ ? And how would it be in the general case whe differentiating implicitly | In the book Thomas's Calculus (11th edition) it is mentioned (Section 3.8 pg 225) that the derivative $dy/dx$ is not a ratio. Couldn't it be interpreted as a ratio, because according to the formula $dy = f'(x)dx$ we are able to plug in values for $dx$ and calculate a $dy$ (differential). Then if we rearrange we get $dy/dx$ which could be seen as a ratio. I wonder if the author says this because $dx$ is an independent variable, and $dy$ is a dependent variable, for $dy/dx$ to be a ratio both variables need to be independent.. maybe? |
public class cripto { static String chiave, mex; static int lungC,lungM, lungAl,lungCh; static String[] aChiave, aMex; static String[] alfabeto = {"a", "b", "c","d", "e", "f","g", "h", "i","l", "m", "n","o", "p", "q","r", "s", "t","u", "v", "z"}; public static void main(String[] args) { // TODO Auto-generated method stub chiave=JOptionPane.showInputDialog(null, "Inserisci chiave di criptografia di lunghezza: "+alfabeto.length); System.out.println("chiave: "+chiave); lungC=chiave.length(); for (int i=0; i<lungC; i++){ aChiave=chiave.split(""); System.out.println(i+": "+aChiave[i]); } mex=JOptionPane.showInputDialog(null, "Inserisci messaggio"); System.out.println("messaggio: "+mex); lungM=mex.length(); for (int i=0; i<lungM; i++){ aMex=mex.split(""); System.out.println(i+": "+aMex[i]); } lungAl=alfabeto.length; lungCh=aChiave.length; System.out.println("Lunghezza array alfabeto: "+lungAl); System.out.println("Lunghezza array chiave: "+lungCh); String[] aCripto=new String[lungM]; if(aChiave.length==alfabeto.length){ for(int i=0;i<lungM;i++){ for(int j=0;j<alfabeto.length;j++){ //System.out.println(i+": "+h+" - "+h1); if(aMex[i]==alfabeto[j]){ aCripto[i]=aChiave[j]; } } } }else{ JOptionPane.showMessageDialog(null, "Lunghezze diverse"); } } } Hy guys, I Made this simple criptography's program but I have the problem that in the for, the program doesn't enter in the "if" even if the equality is verified. if(aMex[i]==alfabeto[j]){ aCripto[i]=aChiave[j]; } can someone help me? sorry for my bad english. | I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? |
I'm really stuck on my scripting because of this problem. I need my script to accept arguments and give me the result but since i have spaces it only displays the first word. eg. cat open.sh echo My name is $1 export start=`date +"%b %d %k:%M:%S %Y"` [oracle@spiderman scripts]echo $start Jul 01 3:03:18 2016 [oracle@spiderman scripts]$sh open.sh `echo $start` The time is Jul I need the output as The time is Jul 01 3:03:18 2016. I need to pass the same output to another complex script. | Or, an introductory guide to robust filename handling and other string passing in shell scripts. I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names). I encountered a problem such as the following: I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators). What is going on and how do I fix it? |
In versions of ubuntu above 16.04 the default display manager is gdm3. I am attempting to remove the guest user from an ubuntu VM but I don't know how to do it without lightdm. How do I do this? I have tried switching to lightdm but I cannot find the lighdm.conf file, only the lightdm.conf.d file, and it is completely blank. I would really appreciate some help. | After I saw , I realized that there are many guest accounts on my system: grep guest /etc/passwd guest-jzXeRx:x:117:127:Guest,,,:/tmp/guest-jzXeRx:/bin/false guest-l5dAPU:x:118:128:Guest,,,:/tmp/guest-l5dAPU:/bin/false guest-FdSAkw:x:119:129:Guest,,,:/tmp/guest-FdSAkw:/bin/false guest-eBU0cU:x:121:131:Guest,,,:/tmp/guest-eBU0cU:/bin/false Moreover, in this moment there is nobody logged as guest, but if somebody will login as guest, a new guest account is created - why, since there are already other guest accounts? After the new guest will log out, his account will be deleted. But why the other guest accounts remain? For what use/purpose? It doesn't mind me at all this guest account, but I want to know if it is okay to delete them manually. |
I made a for loop to save files in a directory but i would like the name of the file to start with zeros this is the code that I made for index, i in enumerate(list): im = PImage.fromarray(i) im.save(dir + '/' + 'data_' + str(index) +'.tiff') And now the file names are data_1.tiff data_2.tiff and so on But I would like them to be data_001.tiff data_002.tiff | What is a Pythonic way to pad a numeric string with zeroes to the left, i.e. so the numeric string has a specific length? |
I installed 18.0.4 LTS as well as rtl8723de drivers The drivers work only when the wifi device is just close to the laptop.. When the wifi device is even slightly away the laptop cannot connect to the wifi device and errors ut saying "Connection Failed Activation of Network Connection failed" Another laptop with Windows OS right next to this Ubuntu loaded laptop works fine and connects to the same wifi with 'full' signal strength I called HP Technical support - HP declined to provide any driver support on laptops loaded with anything other than Windows. Please help what should I do in order to make my new laptops work. Thank you. | My Wi-Fi connection seems to be very weak and the range is very low. It drops by two bars if I just move to the next room and by two if just step outside. The speed is also not fast as compared to what I get from the router on my desktop . My laptop is a HP laptop with RTL8723de module. Can anyone help me in bumping up my Wi-Fi speed? Result of lspci -nnk | grep 0280 -A3: 03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:d723] Subsystem: Hewlett-Packard Company Device [103c:8319] Kernel driver in use: rtl8723de Kernel modules: rtl8723de |
Starting as a High Elf lets me know a single wizard cantrip at level 1. By the time I hit level 3 and get my archetype, Eldritch Knight, I am supposed to know 2. I'm just a bit confused on whether this would mean 2 overall, or 2 in addition to the High Elf starting cantrip, meaning 3 known cantrips at level 3. | I read that High Elves could chose a cantrip from the wizard spells, but is it additional to your own class cantrips, or is it counted as one of them? For this instance, I want to make a Cleric which has at the beginning 3 cantrips. If I chose to be High Elf, would that mean I'll have 4 cantrips, or does it count as one of the 3? |
I updated my ubuntu 16.04 by sudo apt update and encountered this problem . suraj@UTM-600001420:~$ sudo apt update Hit:1 http://ppa.launchpad.net/gerardpuig/ppa/ubuntu xenial InRelease Hit:2 http://in.archive.ubuntu.com/ubuntu xenial InRelease Ign:3 http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial InRelease Hit:4 http://in.archive.ubuntu.com/ubuntu xenial-updates InRelease Hit:5 http://ppa.launchpad.net/sunab/kdenlive-release/ubuntu xenial InRelease Hit:6 http://in.archive.ubuntu.com/ubuntu xenial-backports InRelease Hit:7 http://archive.canonical.com/ubuntu xenial InRelease Hit:8 http://in.archive.ubuntu.com/ubuntu xenial-security InRelease Hit:9 http://ppa.launchpad.net/teejee2008/ppa/ubuntu xenial InRelease Hit:10 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease Err:11 http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial Release 404 Not Found Reading package lists... Done E: The repository 'http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. How to fix this.? | When updating, I get the following error message: W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file. Here, I find another statement on this error: This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need. Is this what I should do? |
I keep getting this error message when ever I try to use i8kctl fan 1 1. I can easily fix it during my current session by entering in sudo modprobe i8k. If there is a way, can someone explain to me how to make it where I don't have to enter anything in, my fans start out on low? I still want to be able to control my fans. I would just like to not have to use the sudo modprobe i8k command every time I turn on my computer. I am very new to Ubuntu, so I'm sorry if I don't understand what you are talking about. I am running Ubuntu 13.10 on a Dell Inspiron 3521. | How can I run scripts automatically when Ubuntu starts up so I don't have to run them manually after startup? |
I was reading the book Mathematics for Machine Learning by Marc Peter Deisenroth, Cheng Soon Ong and A.Aldo Faisal and came across this remark: Remark(Cauchy-Schwarz Inequality). For an inner product vector space $(V,\langle\cdot,\cdot\rangle)$, the induced norm $||\cdot||$ satisfies the Cauchy-Schwarz inequality $|\langle x,y\rangle|\le ||x||\text{ }||y||$ Now I know how to prove this inequality for the dot product and the induced Euclidean norm. But I want to know if there is some general proof of this inequality that can show the truth of this statement for every possible inner product and induced norm. So, my question is whether such a proof exists, and if yes how it works(some clues, not the proof itself), or whether the inequality has to be proven separately for any considered inner product. Thanks for your time! | How many proofs of the Cauchy-Schwarz inequality are there? Is there some kind of reference that lists all of these proofs? |
Prove that the ordinary differential equation $$y'=-y^3+\sin x $$ has a unique solution satisfying $y(0)=y(2\pi)$ It's really hard for me to figure out the existence and the uniqueness. I don't have any clue about this problem. Maybe we can let $u(x)=y(x+2\pi)-y(x)$, then $u(x)$ should satisfy $u(0)=0$ and some differential equations. | So, for the ODE \begin{align} x' = -x^{3} + \sin t, \end{align} we can show that there exists a $2\pi$ periodic solution. To do this, we denote by \begin{align} x(t,\alpha) \end{align} The solution $x(t)$ of the ODE such that $x(0) = \alpha$. Then, let $\alpha \in [-2,2]$. Consider the function $f(\alpha) = x(2\pi, \alpha)$ \begin{align} x > 1 &\Rightarrow x' < 0 \\ x < 1 &\Rightarrow x' > 0. \end{align} Thus, solutions beginning in $[-2,2]$ stay there and we can use Brouwer's fixed point theorem to show that there exists a fixed point of $f$. Therefore there is some $\alpha^{*}$ such that $f(\alpha^{*}) = \alpha^{*}$, which represents the periodic solution $x(t,\alpha)$. Now, my question: Is this $2\pi$- periodic solution unique? Are there other $2\pi$ periodic solutions of this ODE? I have started by trying to subtract two periodic solutions from one another but this hasn't taken me anywhere productive. |
I have an external hard drive that contains several folders. The largest of these folders is a backup that I often update by rsyncing the relevant folders from an encrypted (via Ubuntu's implementation of ecryptfs) internal drive and the remainder are folders that I don't have copies of anywhere else and likely do not have enough storage space to place elsewhere. What I want to do is encrypt my external drive whilst still being able to update its contents via rsync, however I seem to have ran in to the following problems: For the reasons already discussed, any method of encryption that would require me to wipe the external drive is highly undesirable. I would be willing to buy another drive, but that would cause issues mentioned in point #3. A method based on a system like ecryptfs would be undesirable because, to the best of my knowledge, the backup would be made inaccessible if the internal drive's user account becomes unusable (e.g. if the internal drive dies, which is half of the reason why I'd want to have the backup in the first place!). Even if I could get one of these methods to work, I do not believe that they would be compatible with rsync. I often don't have the opportunity to leave my machine turned on for long enough to copy my files from the internal drive to the external drive without the help of rsync. So unless I can get rsync to work with the encryption method, I would almost rather have an unencrypted drive that I could rsync. | I want to save a backup of my data on a remote server, but never want the backup server to see the data unencrypted. Editing a single file and backing up should not result in everything being encrypted and sent again. The remote server should preferably not even know the directory structure (and especially not the directory names). Is there such a solution? |
Is there a way to detect the operating system in ruby? I am working on developing a sketchup tool that will need to detect Mac vs. Windows. | I want my Ruby program to do different things on a Mac than on Windows. How can I find out on which system my program is running? |
I am new to Linux and on of my projects is to find all .config files. I made sure to be logged in as root. What command would I run to do this. | I want to search for all files with the .sql extension in folders and sub-folders (recursive). How can I do this? |
what is the best way to check if a certain Type is nullable or not. some suggested codes out there are unable to test other Type especially string. | How do I check if a given object is nullable in other words how to implement the following method... bool IsNullableValueType(object o) { ... } I am looking for nullable value types. I didn't have reference types in mind. //Note: This is just a sample. The code has been simplified //to fit in a post. public class BoolContainer { bool? myBool = true; } var bc = new BoolContainer(); const BindingFlags bindingFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance ; object obj; object o = (object)bc; foreach (var fieldInfo in o.GetType().GetFields(bindingFlags)) { obj = (object)fieldInfo.GetValue(o); } obj now refers to an object of type bool (System.Boolean) with value equal to true. What I really wanted was an object of type Nullable<bool> So now as a work around I decided to check if o is nullable and create a nullable wrapper around obj. |
We have Always On Availability Group settings, and we have a preferred DB that needs to be in primary all the time even after it reboots. Once a month or so, these 2 servers DB1 and DB2 reboot for upgrade/updates, however whichever come back online first becomes the primary with HA on, but we prefer to always set DB1 as primary when it comes back online no matter what. Are there any configs for this, or should we create a trigger? Thank you | In my environment, I have Db01 and Db02 setup with SQL 2012 AlwaysOn. Db01 is the preferred master as that is where all of the backup jobs reside. Typically, the only time that Db01 is unavailable is during maintenance period of installing Windows Update. Is there a way to always have Db01 be the primary when it is a member of the cluster? Currently, when Db01 rejoins the cluster after a reboot, it is marked as the secondary, since Db02 has become the primary. I would like to see Db01 join the cluster and then automatically (or via a command executed on startup) be designated primary. Db01 and Db02 are both set to SYNCHRONOUS_COMMIT and Automatic Failover Mode |
Is it possible to upvote question and then downvote that question again and upvote again ad so on ? If yes, what is the consequences of this action ? | What limits are there on how I can vote? How often can I vote? How do my votes become locked/unlocked? |
How can I disable the mouse over tooltips on Ubuntu 18.04? When I pass my mouse on any icon the lunch dock or perhaps anywhere else, tooltips appear. I would like to disable this feature/behavior. | I need to know if it is possible and how to disable the Ubuntu 18.04 Dock tool-tips for mouse hover the pinned application. |
I've created a file containing these two lines of code: #!/bin/sh sudo sh -c "sync; echo 3 > /proc/sys/vm/drop_caches" I have ticked (from 'properties') the appropriate box to run the file as a program. Clicking it, I am asked to either run it or run in terminal. The second option works as intended, with the terminal asking for my password then running the command. Is there a way to run the program directly? Currently it doesn't work (presumably because it cannot run the sudo command without password) | Currently, for all my commands that require root access, I have to type them out on a command line. I would like for the GUI to prompt me to key in my password, when sudo is required, instead of having to type out the commands from command line. Is there any way to enable this? Previously one version of Ubuntu desktop had this feature out of the box. This version of Ubuntu (that I am now running) I upgraded from a server installation. I will add, my user account is already added to sudo group. Thus I can run commands such as sudo gedit or sudo apt-get but I'm not able to install software in the Ubuntu Software Center. |
I am working on a ASP.NET project with SQL as back end.(This SQL server is provisioned in cloud using Azure) Part of my Project, I need to store lot of PDF file (like invoices, Customer Updates) etc. The Number of these PDF files are expected to big in number (5TB may be) Now that I provisioned my SQL server in Azure, I am looking best practices On Where I can store the files? Can I use Azure Blob? Is it cheaper? or storing in SQL server itself is better (I know backup is a concern) Or any other suggestion? | Generally, how bad of a performance hit is storing a file in a database (specifically mssql) as opposed to the file system? I can't come up with a reason outside of application portability that I would want to store my files as varbinaries in SQL Server. |
Ok..How to put matrices above matrix when you work with complex equations? I have matrices, such as: I was able to wrote equation in the LaTeX first two matrices on bottom, but the 1x1 matrix on top seems unreal to write in LaTeX. Here is my code: \begin{bmatrix} (\textbf{u}_{1}\textbf{v}_{1}) & \cdots & (\textbf{u}_{1}\textbf{v}_{n}) \\ \vdots & \ddots & \vdots \\ (\textbf{u}_{n}\textbf{v}_{1}) & \cdots & (\textbf{u}_{n}\textbf{v}_{n}) \end{bmatrix} Any suggestions regarding that matrix on very top shown in the attached picture? | How can I write a matrix with a header line that is not bracketed? I have used the following code to produce the results below. In addition of being ugly, it is impractical when I need to align the first row, n1, ..., n6 with the matrix columns. \documentclass{book} \usepackage{amsmath} \begin{document} \[ \ \ \ \ \ \ \ n_1\ \ \ \ \ \ \ \ n_2\ \ \ \ n_3\ \ \ \ \ \ \ \ \ n_4\ \ \ \ n_5\ \ \ \ n_6\] \[ \begin{bmatrix} 1 & -1 & 0 & 0 & 0 & 1\\ 0.960 & -0.977 & 0 & 0 & 0 & 0.983\\ 0 & 1 & -1 & -1 & 0 & 0\\ 0 & 0.977 & 0 & -0.983 & 0 & 0\\ 0 & 0 & 0 & 1 & -1 & -1\\ 0 & 0 & 0 & 0 & 0 & 1\\ \end{bmatrix} \begin{bmatrix}n_1\\n_2\\n_3\\n_4\\n_5\\n_6\end{bmatrix} = \begin{bmatrix}0 \\ 0 \\ 0 \\ 0 \\ 0 \\ 100\end{bmatrix} \] \end{document} |
I'm new to JavaScript and have to build a jdbc application for school. I already have the database in Heidisql and made connection but I the error when I build it. I don't know what the next step is. I have created an arraylist. The error references line 25 in the repository code. public class TechnicianRepository { private Connection connection; public TechnicianRepository() { try { Class.forName("com.mysql.jdbc.Driver"); System.out.println("De Driver is geregistreerd!"); String URL = "jdbc:mysql://localhost/atm_installatie"; String USER = "root"; String PASS = "Br@h!em8891"; Connection conn = DriverManager.getConnection(URL, USER, PASS); System.out.println(connection); System.out.println(); } catch (ClassNotFoundException ex) { System.out.println("Error: unable to load driver class!"); System.exit(1); } catch (SQLException e) { e.printStackTrace(); } } public List<Technician> findAllRecords() { List<Technician> technicianList = new ArrayList<Technician>(); Statement stmt = null; try { stmt = connection.createStatement(); String sql = "SELECT * FROM Technician"; ResultSet rs = stmt.executeQuery(sql); System.out.println("Resultset: " + rs); while (rs.next()) { int tech_id = rs.getInt("tech_id"); String voornaam = rs.getString("voornaam"); String achternaam = rs.getString("achternaam"); String functie = rs.getString("functie"); String email_adres = rs.getString("email_adres"); String telefoonnummer = rs.getString("telefoonnummer"); System.out.println("Tech_ID: " + tech_id); System.out.println("Voornaam: " + voornaam); System.out.println("Achternaam: " + achternaam); System.out.println("Functie: " + functie); System.out.println("Email_Adres: " + email_adres); System.out.println("TelefoonNummer: " + telefoonnummer); technicianList.add(new Technician(tech_id, voornaam, achternaam, functie, email_adres, telefoonnummer)); technicianList.add(new Technician(rs.getInt("tech_id"), rs.getString("voornaam"), rs.getString("achternaam"), rs.getString("functie"), rs.getString("email_adres"), rs.getString("telefoonnummer"))); } rs.close(); } catch (SQLException e) { } finally { //if (stmt != null) { stmt.close(); } } return technicianList; } public class Applicatie { public static void main(String[] args) { TechnicianRepository technicianrepo = new TechnicianRepository(); List<Technician> technicianList = technicianrepo.findAllRecords(); for (Technician technician : technicianList) { System.out.println(technician); } | 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? |
I have model and I want to add the them a bump in cycles and I have this picture any one know how to add this kind of bump in cycles? | I created some texture maps in MindTex to use in Blender, but I can't figure out how to properly hook them up. The maps I have: - Diffuse - Normal - Height - Specular - Gloss - Self Illumination - Reflection - Ambient Occlusion MindTex (left) vs. Blender (right) As you can clearly see it's a pretty big difference. is my material node setup in Blender. In the examples I don't actually use self illumination or reflection images, but including this in the answer would be helpful. |
The minimum amount of charge possible is that of quarks. But it also has mass. Why is there no charge without mass? Or is it there? | Are there any massless (zero invariant mass) particles carrying electric charge? If not, why not? Do we expect to see any or are they a theoretical impossibility? |
What is the use of Hidden layers in Neural Networks? How do we know the role of each hidden layer? | I'm sure many people will respond with links to 'let me google that for you', so I want to say that I've tried to figure this out so please forgive my lack of understanding here, but I cannot figure out how the practical implementation of a neural network actually works. I understand the input layer and how to normalize the data, I also understand the bias unit, but when it comes to the hidden layer, what the actual computation is in that layer, and how it maps to the output is just a little foggy. I've seen diagrams with question marks in the hidden layer, boolean functions like AND/OR/XOR, activation functions, and input nodes that map to all of the hidden units and input nodes that map to only a few hidden units each and so I just have a few questions on the practical aspect. Of course, a simple explanation of the entire neural network process like you would explain to a child, would be awesome. What computations are done in the hidden layer? How are those computations mapped to the output layer? How does the ouput layer work? De-normalizing the data from the hidden layer? Why are some layers in the input layer connected to the hidden layer and some are not? |
Running a later model laptop of the win7 generation now running nicely under 8.1. Now I'm re-paving it and need to ensure that current drivers are available to the next install as painlessly as is possible. I don't want to wade thru the vendor's site hoping to coax them to give me 8.1 stuff when they have me of record at win7. Is there a single place to go to copy folders off to a USB? | I want to reinstall Windows on a machine which has some very obscure drivers. I don't much fancy having to hunt round for them (that's if I'm able to locate them at all). Is it possible to save or backup already installed drivers? If so, how do I do this? How do I then go about installing these 'saved' drivers? |
So I've been trying to get my head around this for weeks. I understand that structs are value types, and that classes are reference types. Where I get confused is the differences in behavior between the two. For example: If I have a bag of potatoes, and each potato is a different size, shape, and weight... The bag would be a 'class' / reference type The potatoes would be a 'struct' / value type Can my potatoes be a class, or do they have to be a struct as the values contained within are different? Basically, the answer to that question will clear everything up for me. Thank you! | When should you use struct and not class in C#? My conceptual model is that structs are used in times when the item is merely a collection of value types. A way to logically hold them all together into a cohesive whole. I came across these rules : A struct should represent a single value. A struct should have a memory footprint less than 16 bytes. A struct should not be changed after creation. Do these rules work? What does a struct mean semantically? |
I have a website that I need to show slightly different content and color scheme to different groups. Is it possible to show different users a different theme simultaneously? So if I send a link to User A) and User B) with a separate _GET value of the theme in the URL, can they both see different themes in the same second? | I plan to use the member plugin by Justin Tadlock I wish to know if how could I, on the front side, auto switch to a theme according to a role status.. for example authors would have the site presented using theme 1 while editor would have the site presenter using theme 2 I would rather have 2 different theme rather than conditionals within one theme structure Thank you in advance |
I have to randomly generate 1000 points over a unit disk such that are uniformly distributed on this disk. Now, for that, I select a radius $r$ and angular orientation $\alpha$ such that the radius $r$ is a uniformly distributed variate from $r \in [0,1]$ while $\alpha$ is a uniformly distributed variate from $\alpha \in [0, 2\pi]$ using the following code r <- runif(1000, min=0, max=1) alpha <- runif(1000, min=0, max=2*pi) x <- r*cos(alpha) y <- r*sin(alpha) plot(x,y, pch=19, col=rgb(0,0,0,0.05), asp=1) Then I look at my sample space and it looks like this: This obviously doesn't look like a sample with uniform distribution over the disk. Hence, I guessed that the problem might be occurring as a result of a lack of independence between the variables $r$ and $\alpha$ in contingency to how they've been linked computationally. To take care of that I wrote a new code. rm(list=ls()) r <- runif(32, min=0, max=1) df_res <- data.frame(matrix(c(-Inf, Inf), byrow = T, nrow = 1)) for (i in 1:32) { for (j in 1:32) { alpha <- runif(32, min=0, max=2*pi) r <- runif(32, min=0, max=1) df <- data.frame(matrix(c(r[i],alpha[j]), byrow = T, nrow = 1)) df_res <- rbind(df_res,df) } } df_res <- subset(df_res, df_res$X1 != -Inf) x<- df_res$X1 *cos(df_res$X2) y <- df_res$X1 *sin(df_res$X2) plot(x,y, pch=19, col=rgb(0,0,0,0.05), asp=1) And, yet again the sample looks non-uniformly distributed over the disk I'm starting to suspect that there is a deeper mathematical problem going on in the vicinity. Could someone help me write code that would create a sample space uniformly distributed over the disk, or explain the mathematical fallacy if any in my reasoning? | I was attempting to simulate injection of random points within a circle, such that any part of the circle has the same probability of having a defect. I expected the count per area of the resulting distribution to follow a Poisson distribution if I break up the circle into equal area rectangles. Since it requires only placing points within a circular area, I injected two uniform random distributions in polar coordinates: $R$ (radius) and $\theta$ (polar angle). But after doing this injection, I clearly get more points in the center of the circle compared to the edge. What would be the correct way to perform this injection across the circle such that the points are randomly distributed across the cirlce? |
I am really stuck on this problem. I don't really understand power series expansions. However, I think this has to do with generating functions. | What is the coefficient of $x^{11}$ in the power series expansion of $\frac 1{1-x-x^4}$? How do I do power series expansions? |
Where do I ask where I should ask a question about something? | There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers. What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment. I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network? I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions. So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe. My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow? Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion. |
First of all, there's no firmware password or anything fancy. I'm trying to diagnose a late-2011 MacBook Pro 15", and I'm trying to get into the single user mode. I press and hold Cmd+S (the left Cmd, if it changes anything) but I'm not getting into the mode. I've tried pressing (and holding) it before pressing the power button, at the same time, a little after etc. I've tried all the combinations. It just won't enter. It will keep booting or let's say (try booting) into the OS where it gets stuck. When I press Cmd+S, however, I can see a very brief terminal in the middle for a very short/split second, and it disappears as I haven't pressed it all. What am I doing wrong? UPDATE: I've tried Cmd+S on another 15" MacBook Pro from 2011, and it behaves the same: It just won't let me into recovery mode. They are both Yosemite, one is 10.10.3, and I can't tell the other one's minor version since I can't boot into the system in any way (and it's owner doesn't know the version either). UPDATE 2: As Buscar웃 asked me about the verbose mode process, I took a video of booting into verbose mode: UPDATE 3: Here's a GIF version of the video. I had to reduce quality and size a lot, but you'd get the general idea: | I've got a Late-2011 15" MacBook Pro stuck in the gray screen when booting AFTER login. I've tried removing the drive (it's non-retina) and booting from a working bootable Yosemite installer, no luck. (it sees the startup USB drive, the progress bar progresses, but stuck at the gray screen again even without a drive. Tried NVRAM reset (cmd option P R), it has reset (the login sound's volume changed) but nothing changed. Tried holding D on startup, AHT doesn't start, instead, it tries to boot into the OS. Tried Cmd V, it sometimes works and displays the verbose output, sometimes, it acts like I haven't even pressed. Again, stuck after login. Tried booting again from USB, I select USB (after seeing both drives correctly), but no luck, it's also stuck. I've stumbled upon this: I've tried booting into single user mode with Cmd S, it worked ONCE, I've disabled the graphics extensions just as shown at that post, restarted, but again, nothing changed. More weirdly, now the Cmd S doesn't work either. It just takes me to login screen without showing the terminal, just as I haven't pressed anything. Why would this happen? Why would a Mac refuse to enter hardware test mode, single user mode, or refuse to boot from a working bootable Yosemite drive both with or without the main drive installed? UPDATE: I've run the AHT and got an error: 4MEM/66/40000000: 0x84e0ec98 It looks like a memory issue, but I'm not sure. UPDATE 2: I've tried reinserting the RAMs and the the problem is not reported anymore. However, the Mac still won't boot. |
Two days ago, I first hit the daily cap limit. A bit later, I got -12 (user removed). Overall, it looks like this: Although, the daily reputation shows up as 190. Is that a bug, or do I get something wrong here? (I saw , but I think that doesn't explain what I see here). | There are many Q&A's around this and the best explanation of daily cap model is from this answer that uses . It is an old answer but gives a good understanding. My confusion is in applying this model to my situation yesterday. On 31/12/2019, I awarded a bounty to , since it became eligible for bounty (2 days after posting it). Subsequently, I got more upvotes (including one accept) which exceeded the daily cap of 200. I am confused about this-loss of reputation due to bounty awarded by me preceeded subsequent gain of reputation so going by the bucket analogy, I should have my rep adjusted accordingly and those 6 up votes (at the bottom of table) should have been credited (rep should have been 177 instead of 117), /reputation shows this 2 219845 (10) 1 219884 (2) 2 170717 (10) 2 219621 (10) 2 219845 (10) 2 219845 (10) 2 218537 (10) 2 219845 (10) 2 219892 (10) 2 219845 (10) 8 219821 (-100) 2 219845 (10) 2 219621 (10) 2 219845 (10) 2 219821 (10) 2 219845 (10) 2 219845 (10) 2 219845 (10) 2 219912 (10) 1 219912 (15) 2 219845 (10) 2 219845 (10) 2 219892 [10] 2 219845 [0] 2 219621 [0] 2 219845 [0] 2 219845 [0] 2 219845 [0] 2 219845 [0] -- 2019-12-31 rep +117 = 27089 -- It is not the 6 votes I am bothered about, it is more about trying to correct my understanding or have I stumbled upon an anomaly? |
I have a .sql file with insert statements in C:\sqldata\MyData.sql. I need to insert data into sqlite database in my Android App using this .sql file. How could I do this? | If your application requires a database and it comes with built in data, what is the best way to ship that application? Should I: Precreate the SQLite database and include it in the .apk? Include the SQL commands with the application and have it create the database and insert the data on first use? The drawbacks I see are: Possible SQLite version mismatches might cause problems and I currently don't know where the database should go and how to access it. It may take a really long time to create and populate the database on the device. Any suggestions? Pointers to the documentation regarding any issues would be greatly appreciated. |
So I am making a game and have a class Players each player has a name and score. I am trying to get user input for the names of each Player object by calling a function and using for loops and setting the players name from user input from the user. I have tried a few things while researching still I have a problem. I saw some people say that Array.toString(arr) is how you print an array of objects. I am now getting an error .\Player.java:13: error: incompatible types: unexpected return value return "Player: " + name + " Score" + score; import java.util.*; class diceGame{ // calling main method public static void main (String[] args){ createPlayersArray(); } //Get the details oto launch game such as the number of players //and collects their names to store in a array public static void createPlayersArray () { Scanner kb = new Scanner(System.in); System.out.println("Please enter the number of players: "); int numOfPlayers = kb.nextInt(); //Player array to hold all the players Player [] playerArray = new Player[numOfPlayers]; //Array to set the players names for (int i = 0; i < numOfPlayers; i ++ ) { System.out.println("Please enter your name: "); String currentPlayerName = kb.next(); playerArray[i] = new Player(currentPlayerName, 0); } System.out.println("This should be the list of players"); for (int i = 0; i < playerArray.length; i ++ ) { System.out.println(Array.toString(playerArray)); } }; } /////////////////////// Player Class////////////////////////// class Player{ public String name; public int score; public Player (String n, int s){ name = n; score = s; } public void nameAndScore (){ return "Player: " + name + " Score" + score; } //Geters and Setter name public String getName(){ return name; }; public void setName(){ return name; } }; It not so much a error but I am getting the memory address displayed: Player@880ec60 Player@3f3afe78 Player@7f63425a Player@36d64342 I would like the console to print: Tom score: 0 Jerry score: 0 | In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the of the array, as defined by Object.toString(): int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(intArray); // prints something like '[I@3343c8b3' But usually, we'd actually want something more like [1, 2, 3, 4, 5]. What's the simplest way of doing that? Here are some example inputs and outputs: // Array of primitives: int[] intArray = new int[] {1, 2, 3, 4, 5}; //output: [1, 2, 3, 4, 5] // Array of object references: String[] strArray = new String[] {"John", "Mary", "Bob"}; //output: [John, Mary, Bob] |
I have a library with a folder which has few items. I want to display the items of this folder to be displayed on home page. We can show all items in the library but is there any way to show items of a folder in library. | I am new to SharePoint 2013. I was curious how to put a WebPart for a Document Library on a page with SharePoint 2013, not 2010. This WebPart would then show the content of a specific library folder and not start at the root of the folder. So say I have a library with multiple folders like "Marketing", "Finance" etc, I want to be able to create a web part that would only show the contents within the “Marketing subfolder and all of it contents. Is this possible? |
Imagine I define a new command as : \newcommand{\seagal}{$\sigma$-algebra} and use it as follows : A \seagal is defined as This will produce a text where is will have "-algebrais defined as" and not "-algebra is defined as" : a space is missing. When I write \mathscr{M} is indeed a \seagal. though, I don't have a space and I shouldn't have one. How could I produce a newcommand that handles both cases correctly ? | I have a definition: \newcommand{\arnold}{Arnold Schwarzenegger} When I refer to it by: \arnold is a it is rendered as: Arnold Schwarzeneggeris a In order to have a space in front of "is" I would need to write \arnold\ is a Is there some other shorter way? |
this is my first post. I'm fairly new to Blender (CG in general) and am having trouble rendering my scene because the only thing being rendered is the world color. I know there were a few other people on this site with this exact situation, but so far every object in my scene is render-activated in the Outliner, all the correct render layers are selected, I am rendering with CPU, and the camera Aperture is correctly set to zero, so I'm not sure what else to look at. It was working earlier today, so I guess I must've accidentally changed something? Edit: My render slot isn't completely empty, only my world color (dark green) is being rendered. | A scene I made is not rendering, at all. This grey screen stays the same and nothing changes. Here are my settings: [ |
Whenever we see a matrix $A=\bigl( \begin{smallmatrix} 3 & 2 \\ 1 & 2 \end{smallmatrix} \bigr)$ and $v=(3, 2),$ we can visualize that $(3, 2)$ represent the coordinates of $\mathbf i$ vector and $(1,2)$ represents the $\mathbf j$ vector. And to visualize $A$ as a whole, we can see it as a matrix that transforms can the vector $v.$ when we multiply it. So, we can visualize $A^{-1}$ as a matrix that undoes the transformation by $A.$ Similarly, the determinant of $A$ gives the area. How can I visualize the transpose of a matrix as well as matrices that have a complex number as an element? Thank you. | I can follow the definition of the transpose algebraically, i.e. as a reflection of a matrix across its diagonal, or in terms of dual spaces, but I lack any sort of geometric understanding of the transpose, or even symmetric matrices. For example, if I have a linear transformation, say on the plane, my intuition is to visualize it as some linear distortion of the plane via scaling and rotation. I do not know how this distortion compares to the distortion that results from applying the transpose, or what one can say if the linear transformation is symmetric. Geometrically, why might we expect orthogonal matrices to be combinations of rotations and reflections? |
Why are we using RMS value over average value for a periodic wave? | $$P = I_{\text{eff}}^2 \times R$$ where \$I_{\text{eff}}\$ is the effective current. For power to be average \$I\$ must be average current, so I am surmising that the effective current is the average current. In that case, why is \$I_{\text{eff}}\$ not simply $$I_{\text{eff}} = \frac{1}{t}\int_{0}^{t} |i|dt$$ Instead it is defined like so: $$I_{\text{eff}} = \sqrt{\frac{1}{t}\int_{0}^{t} i^2dt}$$ Thus, using these two expressions to calculate \$P\$ results in different answers. Why is this so? It makes no sense to me. I can only guess that I am misinterpreting the effective current is the average current. If this is not the case, however, I do not see how \$P\$ can be the average power when \$I_{\text{eff}}\$ is not the average current. |
If $f_n, f \in L^p, 1\leq p < +\infty$ and $f_n \rightarrow f$ almost everywhere, and $\|f_n\|_p \rightarrow \|f\|_p$, then $f_n\rightarrow f$ as for the norm. Could you give me some hints how to show it?? What does convergence as for the norm mean?? EDIT: From Fatou`s lemma we have that $$\int \lim \inf [2^{p-1}(|f_n|^p+|f|_p)-|f_n-f|^p]d\mu \leq \\ \lim \inf \int [2^{p-1}(|f_n|^p+|f|^p)-|f_n-f|^p]d\mu \\ \Rightarrow 2^{p-1}\int \lim \inf (|f_n|^p+|f|^p)d\mu+\int \lim \inf (-|f_n-f|^p)d\mu \leq 2^{p-1}(\lim \inf \int |f_n|^pd\mu +\lim \inf \int |f|^pd\mu )+\lim \inf (-\int |f_n-f|^p d\mu) \\ \Rightarrow 2^{p-1}[\int \lim \inf |f_n |^pd \mu+\int \lim \inf |f|^pd \mu]-\int \lim \sup |f_n-f|^pd \mu \leq 2^{p-1}[\lim \inf \int |f_n|^pd \mu+\lim \inf \int |f|^p d\mu]-\lim \sup \int |f_n-f|^pd \mu \ \ \ \ \ (*) $$ Knowing that $||f_n||_p\rightarrow ||f||_p \Rightarrow \left ( \int |f_n|^p\right )^{1/p}\rightarrow \left ( \int |f|^p\right )^{1p}$ , we have that $\lim \inf |f_n|^p=|f|^p$ Therefore, $$(*)\Rightarrow 2^{p-1}\int (|f|^pd \mu+\int |f|^pd\mu)-\int \lim \sup |f_n-f|^pd \mu \leq 2^{p-1}(\lim \inf \int |f_n|^pd \mu +\int |f|^pd \mu)-\lim \sup \int |f_n-f|^pd \mu \\ \Rightarrow 2^{p-1}\int |f|^pd \mu-\int \lim \sup |f_n-f|^pd \mu \leq 2^{p-1}\lim \inf ||f_n||^p_p-\lim \sup \int |f_n-f|^pd \mu \\ \Rightarrow 2^{p-1}||f||^p_p-\int \lim \sup |f_n-f|^pd \mu \leq 2^{p-1} ||f||^p_p-\lim \sup \int |f_n-f|^pd \mu \\ \Rightarrow \lim \sup \int |f_n-f|^pd \mu \leq \int \lim\sup |f_n-f|^pd \mu \\ \Rightarrow \lim \sup ||f_n-f||^p_p \leq \int \lim \sup |f_n-f|^pd \mu =0, \text{ since } f_n\rightarrow f \text{ almost everywhere } $$ So, we conclude that $||f_n-f||_p\rightarrow 0$. | Let $1\leq p < \infty$. Suppose that $\{f_k\} \subset L^p$ (the domain here does not necessarily have to be finite), $f_k \to f$ almost everywhere, and $\|f_k\|_{L^p} \to \|f\|_{L^p}$. Why is it the case that $$\|f_k - f\|_{L^p} \to 0?$$ A statement in the other direction (i.e. $\|f_k - f\|_{L^p} \to 0 \Rightarrow \|f_k\|_{L^p} \to \|f\|_{L^p}$ ) follows pretty easily and is the one that I've seen most of the time. I'm not how to show the result above though. |
I want to know how to solve this using contour integration: $$\int_0^{\infty} \frac{\sin(x)}{\sqrt{x}}dx.$$ So I let the integral become: $$\oint_c \frac{\sin(z)}{\sqrt{z}}dz$$ where c is a "half doughnut" shape avoiding the singularity at z = 0 and extending into the upper half of the complex plane towards infinity. $$\oint_c = \int_{up} + \int_{-R}^{- \epsilon} + \int_{low} + \int_ {\epsilon}^R = 0$$ (Because no singularities are actually contained within the contour.) By a bound argument, the $\int_{up}$ contributes nothing to the integral. Therefore: $$\lim{R \to \infty}, {\epsilon \to 0}$$ $$- \int_{low} = \int_{- \infty}^{\infty} $$ Where $\int_{low}$ is the integral over the bump going over the point z = 0. So can I use the Cauchy Integral theorem to say $$\int_{low} = \pi i\, \text{Res} \left( \frac{\sin x}{ \sqrt{x}}, 0 \right)$$ Because there is no residue for this function, which would imply the integral is zero, which I know it is actually $\sqrt \frac{ \pi}{2}$. | Numerically it seems to be true that $$ \int_0^\infty \frac{\sin x}{\sqrt{x}}dx=\sqrt{\frac{\pi}{2}}. $$ Any ideas how to prove this? |
I just bought a Sony DVD+R but I don't know if it's either +R or +RW. I assume it is a DVD+RW since the mark "RW" is written at the bottom of the disc. Same for my built-in desktop burner, it has a "RW" mark and tiny "DVD+R DL" is written below the "RW" mark. When I'm trying to erase the content of the DVD. I used several DVD erasers, including . Although the software is different, the result is the same, this is the error message: I'm not sure the DVD is really "ReWritable", because the DVD Burner I used to burn DVD said the disc status is "DVD+R". That's weird, because apparently my DVD discs are rewritable. (I'm wondering it is rewritable...) Are the discs non-rewritable? If so, could you tell me what does the "RW" mark stand for? And also, the "AccuCORE" :) Though I'm actually wanting to know is it rewrite compatible. | If you look at this product: you can clearly see that it is a DVD+R, i.e. once it is written, it cannot be erased/rewritten. Then what does the "RW" logo (in the lower right corner) mean? I thought it stood for ReWritable, but experimenting with the medium shows that it is not. |
I haven two passports (US & Irish). I'm currently traveling on my US passport but it's getting full & want to switch to my Irish passport so I will be able to get a visa when in Indonesia. Will I have any problems at immigration? Should I just stay in Malaysia and get another American passport? | I am a citizen of two different countries, and have two passports. How should I use my passports when traveling? |
When I browse questions on a site I'm registered for, I can see all questions - newest, featured, frequent, votes, active, and unanswered. But on sites I am not registered for, I can browse only newest questions. Sometimes I just want to see the highest voted questions on a site, and not ask or answer any. I recall I used to be able to do this (every developer's least favourite phrase), am I imagining things? | I think this is platform wide (all SE sites). Logout Choose a tag, eg. on SO Try to sort questions by something other than newest No matter what sorting is chosen, questions are sorted by newest |
Ok, so I was trying to edit files in the the WindowsApps directory (I made this post ) and I set myself as the owner of all of the folders in this directory. Then, this made Windows Store unlaunchable, so I began fiddling with the permissions, which was a big mistake. If I add a permission rule giving "All application packages" full control of the WindowsApps folder and subfolders, then Windows Store begins functioning again, but this seems like a band-aid fix so I tried to find another solution. I tried resetting Windows twice (once keeping files and once losing files) but this issue still persists. I am running 64-bit Windows 10 Pro - I am preparing to reinstall Windows with a USB drive created through the but I am worried this will install a standard version of Windows. Will I be able to keep the Pro version? Does anyone have any other ideas - maybe ways to reset permissions of an entire folder tree or is there a way to delete the entire WindowsApps directory and have Window update repair it? At this point, I am considering just using my computer as-is, because I don't really use the Windows store.. please help! | I had to take ownership of the special folder C:\Program Files\WindowsApps to fix . The issue is now resolved, so I'd like to reset the permissions to the way they were before I took ownership of the folder. I reverted NT SERVICE\TrustedInstaller to the owner and removed my account's permission entries: But I still have full control of the folder and can browse the folder in Explorer without getting the usual warning that I would have to take ownership: Is it possible to restore the default permissions of this folder? |
I created a blogspot website few days back and even published a blog over there, but it is not indexed yet. What may be the reasons. I am 10 years old and a newbie here. So can anyone help me with my website being indexed? Website Link: | 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? |
Im sorry if this is stupid or obvious, but why $$ e=\lim_{n\rightarrow \infty}\left(1+\frac{1}{n}\right)^n$$ AND $e$ is the unique positive number for which $$ \lim_{h\rightarrow 0}\frac{e^h-1}{h}=1$$? I mean, how do we know that these two definitions are equivalent? Again, maybe it's easy, but I'm just beginning calculus and our teacher just dropped those two definitions... | Show that, $$e=\lim_{x\to \infty} \left(1+\frac{1}{x}\right)^x $$ Is the same number that satisfies, $$\lim_{h\to0} \frac{e^{h}-1}{h} = 1 \tag{*}$$ You don't have to do that if it's too cumbersome, but (*) is used to find the derivatives of real exponential functions. I know that definitions are not to be proven but I'm looking for some derivation or intution for the claim that (*) is a legitimate definition for e, and furthermore, a proof that limit in (*) exists. |
It is well known that in an arbitrary metric space a sequentially compact subset is closed and bounded, under which hypothesis does the converse hold? Or in other words, are there spaces, other than $\mathbb{R}^n$ (or any finite dimensional Banach space) with this property? | From A metric space (or topological vector space) is said to have the Heine–Borel property if every closed and bounded subset is compact. Any subset of a Euclidean space, including itself, has the Heine–Borel property. I was wondering if there are more general types of metric spaces, topological vector spaces, or whatever space where boundedness and closedness can make sense, such that they also have the Heine–Borel property? Or does the Heine–Borel property characterize subsets of Euclidean spaces? Thanks and regards! |
So I want to type commands like \geq_{\alpha} or \leq_{\alpha} into the user section (the bit with the symbol of the person, above PStricks, and below Left/Right). Fine, but how do I save these commands? I closed texmaker and when I started again, the commands were all gone. It seems dumb to keep typing them in again and again and again. | I would like to save my customised completion (user> customise completion) so that every time I close and re-open texmaker, I don't have to redefine it. How can I do that ? Thanks in advance, |
i'm a beginner programmer and i was wondering if there was a way to do this, ideally i would have it so that it only asks for the input for 5 seconds, cancels and moves on if nothing has been pressed would i need a separate thread?, is there even a way to do something like this in c#? or is this just a limitation of using the console? | I have a console app in which I want to give the user x seconds to respond to the prompt. If no input is made after a certain period of time, program logic should continue. We assume a timeout means empty response. What is the most straightforward way of approaching this? |
I just want to ask a very elementary question. When we introduce a "definition" in a first order logical system. For example when we say Define: $Empty(x) \iff \not \exists y (y \in x) $ Isn't that definition itself an "axiom", call it a definitional axiom. I'm asking this because the one place predicate symbol Empty() is actually new, it is not among the listed primitives of say Zermelo, which has only identity and membership as primitive symbols. So when we are stating definitions are we in effect stating axioms? but instead of being about characterizing a primitive, they are definitional axioms giving a complete reference to a specified set of symbols in the system. Is that correct? Now if that is the case, then why we don't call it axiom when we state it, I mean why we don't say for example: Definitional axiom 1) $Empty(x) \iff \not \exists y (y \in x)$ Zuhair | I am wondering what the difference between a definition and an axiom. Isn't an axiom something what we define to be true? For example, one of the axioms of Peano Arithmetic states that $\forall n:0\neq S(n)$, or in English, that zero isn't the successor of any natural number. Why can't we define 0 to be the natural number such that it isn't the successor of any natural number? In general, why is an axiom not a definition? Are there cases where we can formulate definitions as axioms or vice versa? |
I encountered the following induction proof on a practice exam for calculus: $$\sum_{k=1}^nk^2 = \frac{n(n+1)(2n+1)}{6}$$ I have to prove this statement with induction. Can anyone please help me with this proof? | I am just starting into calculus and I have a question about the following statement I encountered while learning about definite integrals: $$\sum_{k=1}^n k^2 = \frac{n(n+1)(2n+1)}{6}$$ I really have no idea why this statement is true. Can someone please explain why this is true and if possible show how to arrive at one given the other? |
Sometimes when I feel that a "late answer" needs editing, there's already a suggested edit over there. But approving it (of course after inspection) doesn't enable the "I'm Done" action. On top of that, it switches me to "Review Suggested Edits". Though I come back to that page, even refreshing it doesn't work. Shouldn't this be changed? | I was in the first posts review queue and chanced on a post with a suggested edit. (Note: I have enough reputation to review suggested edits.) I clicked on “edit (1)” and was taken into the suggested edits queue. When I approved the suggested edit, I was taken to the next suggested edit, and so on until there were no more suggestions (“There are no items for you to review.”, still in the suggested edits queue). In this situation, I think it would make more sense if I was brought back to that post I was working on in the first posts queue, as soon as I acted on its suggested edit. Alternatively, the suggested edit should be shown in the same kind of pop-up as on a question thread page. The same goes for other queues (late answers, low quality, etc.). |
I was thinking about the question above and can't find an easy way of proving it. Any suggestions? | Prove: Let $R$ a Artinian commutative ring with $1 \neq 0$. If $I$ is prime, then $I$ is maximal. I got stuck on this. I understand that every ideal is generated by finitely many elements. Here is my approach: It's enough to prove the following implication: $$ R/I \ \text{is a domain} \quad \Rightarrow \quad R/I \ \text{is a field}$$ Then only finding an inverse is left. So let $x \in R$ in arbitrary. We have to find an inverse element of $x+I \in R/I$, that as an element y so that $x \cdot y \in I+1$. We denote $I = (x_1, x_2, \cdots, x_n)$. Now I have to find y so that $xy -1 = r_1 x_1+ r_2 x_2 + \cdots + r_n x_n$. This is where I no more knew what to do. Your advise will be appreciated. |
Consider this sentence: The damage extended 400 yards either side of the island. Should 400 yards be considered as the object of 'extended', an adverbial of extent, or subject complement to 'the damage'? | In this sentence: This book cost me 20 dollars. Is 20 dollars a direct object or a predicative complement? |
In my code, I am creating a temp table using select * into #tempTable. Temp table contains the huge number of records and I need to retrieve data from it many times in my code so I created a clustered index on it. But somehow I am not getting data in correct order as per created index. I know I can do it simply by putting the order by clause, but my question is why I am not getting data in the correct order even if I am forcing the optimizer to use the particular index? Below is my sample code: ----------- Sample code ---------------------------- ;with CTE1 as ( select col1 ,col2 ,-- - -- - - from table1 union select col1 ,col2 ,-- - -- - - from table2 -- few more tables in union -- ) , CTE2 as ( select * ,RowNumber = RowNumber() over (order by case when @sortOrder = 0 then case when @sortColumn = 'Date' then [tdate]......some more dynamic order by conditions.......... end end asc ) from CTE1 inner join from TABLE3 on -- some conditions ) select * from CTE2 into #TempTable; Then add the clustered index: create clustered index IX_TempTable_RowNumber on #TempTable (RowNumber asc); select * from #TempTable with (index (IX_TempTable_RowNumber)); ----------------- End of sample code --------------------- Even I checked the table scheme and index details using exec tempdb.dbo.sp_help N'#TempTable'; select * from tempdb.sys.indexes where name = N'IX_TempTable_RowNumber' And it seems correct to me. What am I missing here? | In order to better understand the SQL Server query processor, I've been thinking about how the ORDER BY clause works, and how SQL Server provides results. It appears SQL Server will provide results in exactly the same order for any given set of data that remains the same and never, ever changes. Once you introduce any kind of uncertainty such as developers changing something, the order of results can no longer be expected to be the same. Simply seeing the results in the same order, each time you press F5 does not guarantee the results you expect. Try this: USE TempDB; DROP TABLE TestOrderBy; DROP TABLE TestOrderBy2; CREATE TABLE TestOrderBy ( ID INT NOT NULL CONSTRAINT PK_TestOrderBy PRIMARY KEY CLUSTERED IDENTITY(1,1) , SomeData varchar(255) ); INSERT INTO TestOrderBy (SomeData) VALUES ('E'); INSERT INTO TestOrderBy (SomeData) VALUES ('D'); INSERT INTO TestOrderBy (SomeData) VALUES ('C'); INSERT INTO TestOrderBy (SomeData) VALUES ('B'); INSERT INTO TestOrderBy (SomeData) VALUES ('A'); CREATE TABLE TestOrderBy2 ( ID INT NOT NULL CONSTRAINT PK_TestOrderBy2 PRIMARY KEY CLUSTERED IDENTITY(1,1) , SomeData varchar(255) ); INSERT INTO TestOrderBy2 (SomeData) VALUES ('E'); INSERT INTO TestOrderBy2 (SomeData) VALUES ('D'); INSERT INTO TestOrderBy2 (SomeData) VALUES ('C'); INSERT INTO TestOrderBy2 (SomeData) VALUES ('B'); INSERT INTO TestOrderBy2 (SomeData) VALUES ('A'); SELECT SomeData FROM TestOrderBy UNION ALL SELECT SomeData FROM TestOrderBy2; CREATE INDEX IX_TestOrderBy_SomeData ON TestOrderBy (SomeData); CREATE INDEX IX_TestOrderBy2_SomeData ON TestOrderBy2 (SomeData); SELECT SomeData FROM TestOrderBy UNION ALL SELECT SomeData FROM TestOrderBy2; The results: As you see, adding a simple index on the fields selected in the query alters the order of the results. From here on, I'm adding ORDER BY unless I truly don't care. |
I had made two of my friends buy CS:GO and today, while texting in a group I said "I made both of you buy the games". My friend corrected me with "*game". Was I wrong? I tried googling but couldn't find anything. | The usage of singular and plural has always been confusing for me. I often see sentences like these People are using cell phones. People are using a cell phone. Does the first sentence mean everyone has a phone and they are all using their own? Does the second sentence mean they are sharing one cell phone? If I see a group of people holding a cell phone in their hand(s), <- even this is confusing for me, should I use the first sentence then? Another example: you see two men, and both of them are carrying a bag. Which sentence should I say/use? They are carrying backpacks They are carrying a backpack Could you please make it clear for me? |
So I get that work is done when a net force converts potential to heat or kinetic. But I also understand that osmosis is driven purely by entropic processes. There is no net force, only a statistical change driven by random motion. So where does the energy, aka osmotic power or pressure actually come from. It seems contradictory that it is purely entropic yet releases free energy. | A thought experiment: A U-shaped tube with semi-permeable membrane at the base. The tube is completely thermally isolated from its surroundings. The liquid (solvent) is at some temperature $T$. When solute is added to one side of the tube the fluid level on that side rises until the increased pressure due to gravity ($\rho gh$) equals the osmotic pressure. If I understand correctly, osmotic pressure could be used to do work (i.e. lift a weight as the solvent level in one side of U-shaped tube increases). Where does this energy come from? I guess it must be from the internal energy of the fluid. At this point has the temperature of the fluid decreased?? If so, has it decreased by exactly the work done against gravity divided by the specific heat of the fluid? What does the quantitative treatment of this problem look like? |
So basically what I want to accomplish is to capture all the raw, mixed audio coming from my system as a raw stream of audio data and send it over the network. In terms of UX, the experience I would want to achieve would be that I can select this "virtual audio output device" from my system settings in Ubuntu, just as if it were a pair of bluetooth headphones connected to my machine, or a projector with speakers plugged into the HDMI port for example. What I actually want to do in my virtual audio device would be to have access to the raw audio data, so that I could chop it up into packets and send it over a UDP socket. What would be the audio API's I would use to accomplish this? I have done a bit of searching, and it looks like maybe implementing a PulseAudio sink is what I would need to implement? In other words, is PulseAudio what's behind the scenes when I am choosing output devices in the settings GUI in Ubuntu 18.04? Also, once I have created my "virtual output device", how do I get the system to recognize it as one of the output options? | There is a Linux (Manjaro) PC without an audiocard. Is it possible to create a virtual audio device? The usage idea is the following: virtual audio device process a sound, then there is a server connected to our sound channel and it transfer the sound to the client (smartphone). |
I cannot boot to my USB hard drive with ubuntu as I do not see an option. I have rearranged the boot menu and it still hasn't worked I am using a gigabyte motherboard and at the top of my bios it says 1984-2008 I have been stuck on this for 2 days now | I have a laptop with Ubuntu installed as the only OS. I also have a USB stick with a Windows 7 installation on it. I want to install Windows from the USB stick on my laptop but when I try to restart the laptop to get access to BIOS, I can't seem to find the command for it, its like it skips everything and just says Ubuntu and then takes me to the login screen. How do I change the boot priority to USB in Ubuntu? |
When I was reading an English web site on the Internet (BBC's 6 Minutes English), I came across this sentence: At the weekends, me and my sisters didn't go to cybercafes or the cinema or hang around the park smoking cigarettes like other teenagers. I've never seen "me" used as the subject and placed at the beginning of a sentence, so I was surprised to see this. I think of course "I and my sisters didn't go" is better, but is "me and my sisters didn't go" accepted as a colloquial expression by English-speaking people? | I've always been taught to put myself last when referring to myself in the same sentence as others but the usage of "me and..." seems to be everywhere these days. The misuse of the word "me" instead of "I" aside, is there some new rule I haven't heard of? Shouldn't we put ourselves last regardless of the "me"/"I" usage? Examples of "correct" usage: My friends and I went for some ice cream. Did you see my friends and me at the ice cream stand? Examples of "incorrect" usage: Me and my friends went for some ice cream. Did you see me and my friends at the ice cream stand? Note: I was also taught that the only person who could put themselves first was the queen. |
I have a , which I am planning to put into BeagleBoard-xM, in order to achieve wireless communication (LAN). However, I can't find it's IP address. I mean, I have to know it's IP address in order to connect with BeagleBoard-xM via a terminal emulator. For the moment, I have this device connected via Ethernet on my router. My router's setting page shows I have this device connected, but no further information. Is there any way to find the IP address of the Wireless Access Point? I hope of being understood. Any help would be really appreciated. | I 'm trying to install wireless access point device EP-2906, on my Desktop PC running Windows 7. Here is the . Page 7 says how I can set up it's IP address, but I can't find Wireless Network Connection icon. Is this because of my Desktop PC and in this case how can I set up a static private IP address for this device? |
With HTML / CSS, I need to get the footer be placed on the bottom of the page even if there is no enough content. In case there is lot of content causing an scroll, is very easy to achieve this. The problem came up when there is no enough content because in that case the footer goes up. Here you have an image that could clarify this more: I have the following starting code: CSS body { margin: 0; } #header, #content, #footer { padding: 10px; } #header { height: 100px; background-color: #abcdef; } #content { bottom: 100px; left: 0; right: 0; background-color: #F63; overflow: auto; } #footer { position: fixed; bottom: 0; left: 0; right: 0; height: 100px; background-color: #abcdef; } HTML <div id="header"> There is the Header </div> <div id="content"> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> hello world<br/> </div> <div id="footer"> There is the Footer </div> Jsfiddle preview: (try resizing the height of the window) Any idea on how to achieve this? IMPORTANT I need a working solution also for IE (ver >= 11), not just FF and Chrome. | I have a simple 2-column layout with a footer that clears both the right and left div in my markup. My problem is that I can't get the footer to stay at the bottom of the page in all browsers. It works if the content pushes the footer down, but that's not always the case. |
I need to extract 'Processed & Soft Cheese1' from the below response: 1.)"departments":["Processed & Soft Cheese1"], I am trying departments":["(.+?)", but it doesn't work. Can some one please help to create regex for the same | I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps. It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps? |
I have read in thermodynamics that a body with high temperature radiates electromagnetic radiation. Does the frequency of waves increases with temperature? What is the mechanism? How does temperature does that? | By conservation of energy, the solid is left in a lower energy state following emission of a photon. Clearly absorption and emission balance at thermal equilibrium, however, thermodynamic equilibrium is a statement of the mean behaviour of the system, not a statement that the internal energy is constant on arbitrarily short timescales. The energy has to come from somewhere during emission, and go somewhere during absorption. Energy in a solid can be stored as kinetic and potential energy of electrons and nuclei, either individually or in collective modes such as phonons and plasmons. In thermal equilibrium energy will be stored more or less in various forms depending on the temperature and material. However, even if most of the thermal energy in a particular solid at temperature $T$ is stored in the form of phonons, it could be that phonons primarily interact with light indirectly via electrons, e.g. a phonon excites an electron in a phonon-electron interaction, which can interact with light via the EM field. Given that light is an EM field, it makes sense to me that it is emitted and absorbed by charged particles. The electron-photon interaction is probably dominant for visible and ultraviolet light, given that metals are opaque, while semiconductors and insulators are transparent to (visible and UV) light with energy lower than their bandgap. However, once you get into energies in the IR and below, or X-rays and above, other mechanisms apparently take over. For example, on the high-energy end of the spectrum I've heard that gamma rays can interact directly with nuclear degrees of freedom, which is reasonable considering that gamma rays are emitted during a lot of nuclear reactions. A review of might give clues to important light-matter interactions over a broad range of wavelengths. Whether all of the these processes are involved in blackbody emission is a somewhat different question. What physical processes mediate energy transfer during blackbody emission, and in which energy ranges are the various processes dominant? |
I just noticed that my user name is no longer then same, As recently as a few months ago, my user name was bonaca, but now it is user182196. Because I can't see my user name in the new topbar anymore, I'm not exactly sure when it was changed. What is causing this and what should I do? | This user is only displaying 56 rep. But surely (s)he has much more than that. The user has also never given out any bounties. Also, badges are missing: |
I have a two shapefiles. One of neighborhoods and one of points. The point file was originally a spreadsheet of X,Y coordinates. but have been exported to shapefile. They display but not over the neighborhood shapefile like they should. I've tried reprojecting, project tool and define projection. It still will not overlap. Everything is displaying in US (Feet). What is wrong? Using arcmap 10.4 Here are the projection data in the Layer source: Point file: Projected Coordinate System: NAD_1983_StatePlane_Pennsylvania_South_FIPS_3702_Feet Projection: Lambert_Conformal_Conic False_Easting: 1968500.00000000 False_Northing: 0.00000000 Central_Meridian: -77.75000000 Standard_Parallel_1: 39.93333333 Standard_Parallel_2: 40.96666667 Latitude_Of_Origin: 39.33333333 Linear Unit: Foot_US Geographic Coordinate System: GCS_North_American_1983 Datum: D_North_American_1983 Prime Meridian: Greenwich Angular Unit: Degree Neighborhood file: Projected Coordinate System: NAD_1983_StatePlane_Pennsylvania_South_FIPS_3702_Feet Projection: Lambert_Conformal_Conic False_Easting: 1968500.00000000 False_Northing: 0.00000000 Central_Meridian: -77.75000000 Standard_Parallel_1: 39.93333333 Standard_Parallel_2: 40.96666667 Latitude_Of_Origin: 39.33333333 Linear Unit: Foot_US Geographic Coordinate System: GCS_North_American_1983 Datum: D_North_American_1983 Prime Meridian: Greenwich Angular Unit: Degree Here's a sample of the Lat Long Coordinates: Lat1 Long1 39.93128729 -75.14691545 39.93130836 -75.14711798 39.93143481 -75.14845446 39.93144498 -75.14853968 39.93117173 -75.14714819 39.93099668 -75.14705857 39.9310071 -75.14715449 39.93101477 -75.14725051 39.93119391 -75.14848865 | I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I cannot figure out how to make the other 3 show up at once on top of each other. Before I opened ArcMap, I used ArcCatalog where I right-clicked 3/4 of the shapefiles and clicked Properties → Coordinate system → Import and then clicked on my Trees layer, which has the coordinate system I want the other 3 to have. But when I opened ArcMap the 4 layers did not overlap, nor could I move them above or below each other. |
The comparative for fussy is fussier. But is it acceptable to say, for example, "Less affection will make the baby more fussy"? (Is it so awkward to use "less X, more Y" in this way?) | I know the rule for making the comparative and superlative form for two-syllable words ending in y, replace the -y with i and use -er and -est: hap.py → happier → (the) happiest ti.dy → tidier → (the) tidiest fun.ny → funnier → (the) funniest Instead for two-syllable adjectives which do not end in -y, use more and most: bor.ing → more boring wor.ried → more worried care.ful → more careful tra.gic → more tragic However, there are inexplicable exceptions: The Free Dictionary says the comparative and superlative form of is cleverer and cleverest. Yet to my ears He's more clever than I thought sounds more formal and correct. Google produces a total of for “he is more clever than” and for the contracted form, “he's more clever than”. Similarly, Google yields and for “he's cleverer than” and “he is cleverer than” respectively, which suggests there is very little to choose between the two comparative forms. Meanwhile, TFD insists that the comparative and superlative form of is simpler and simplest. Google seems to concur and produces for “it is simpler” compared to only for “it is more simple”. The two-syllable adjectives that I am aware of, which have both kinds of comparative and superlative forms are: clever → cleverer/more clever → cleverest/(the) most clever common → commoner/more common → commonest/(the) most common gentle → gentler/more gentle → gentlest/(the) most gentle humble → humbler/more humble (etc.) hollow → hollower/more hollow narrow → narrower/more narrow polite → politer/more polite quiet → quieter/more quiet simple → simpler/more simple stupid → stupider/more stupid subtle → subtler/more subtle Etymologically speaking, is there any explanation for this? Is it a recent trend? It seems to me that the number of two-syllable adjectives that add the suffix -er and -est are increasing. And finally, is there a trick or rule which I can teach my advanced private students? With younger learners and beginners I teach the “rule” that I mentioned at the beginning—so much simpler! :) EDIT December 11, 2019 I shall never ever understand Google's algorithms and how they produce their statistics. In the end, for the sake of clarity, the number of results have been substituted and updated with the number of pages each search produced. |
I'm trying to make a realistic render, but I'm having some troubles with lights and reflections In this scene I have three lights around the object, the trouble is in the corners. I can't find why the reflection is not uniform across both parts of the meshes. Is the same object with two meshes, the entire object has the same material and I'm using the Blender Render (not cycles) and ambient occlusion. (Also applied "smooth" to the lateral faces) | I frequently come to the problem of having a mesh with parts I would like to render smooth and "hard" edges connecting them. How can I set the mesh to show the sharp edges but render everything else smooth? In the example I would like the sides of the individual cylinders render smooth but the intersection between bottom and top to be sharp/flat |
I don't know my email that I used to create my Pokemon go account. Before it just logged me into my account and I count start playing the game. I hit the log into another account by accident and now it just goes to that screen and I can't get back to the game. | So I had 20+ Pokemon on my account and today when I tapped on the app, it brought me back to the original screen when you first start playing. My friend who signed up tested using my username when she first started and my username was unavailable, meaning the account still exists. I don't have the password for the account, but I do have the email. So I wanted to know if it was possible to log back into an account? |
I hope someone can help me, as this can help boost my rendering times. I created a new video sequence project and double checked in the settings - my GPU is recognized, screenshot: When I render the video though and check the gpu temperature, it is pretty normal (60-65 degrees). When I play games, it usually peaks up to 80-100 degrees, so I would expect something similar when rendering with Blender. Does Blender use the GPU when using a video sequencer template? How can I double check if Blender is using my gpu? I also have ffmpeg with h264_nvenc enabled (I can measure the difference in the console, up to 100% more speed), but cannot see this listed in the rendering options: | I'm currently using Blender for video editing. I have an AMD R7 and I have configured OpenCL in my user settings. However, it doesn't seem to make rendering video any faster. Can the GPU be leveraged in this specific scenario or is it exclusively for 3D editing that the benefits can be seen? Update #1 FWIW, exported in Blender using lossless method and will be encoding using VidCoder. Note, VidCoder uses all the cores on my system. |
Show that if $gcd(x, y) = 1$ then $gcd(x − y, x + y)$ is either $1$ or $2$ I think the question is asking me to show if the $\gcd(x,y)$ then the $\gcd(x-y,x+y)$ is $1$ or $2$. so, for the first bit. Let $d=\gcd(a,b)d=\gcd(a,b)$; by definition there are integers $a'a′$ and $b'b′$ such that $a=a'da=a′d$ and $b=b'db=b′d$, so $a'dx+b'dy=da′dx+b′dy=d$. Dividing through by $dd$, then $a'x+b'y=1′x+b′y=1$. Let $e=gcd(x,y)e=gcd(x,y)$. As before, there are integers $x'x′$ and $y'y′$ such that $x=ex'x=ex′$ and $y=ey'y=ey′$. Substituting these into the previous equation, we get $a'ex'+'ey'=1a′ex′+′ey′=1$, or $e(a'x'+b'y')=1e(a′x′+b′y′)=1$. Since $a'x'+b'y'a′x′+b′y′$ is an integer, this implies that $e=1$ or $e=−1$: these are the only divisors of $11$. But $e$ is a greatest common divisor and hence by definition positive, so $e=1$ | If $a,b$ are positive integers such that $\gcd(a,b)=1$, then show that $\gcd(a+b, a-b)=1$ or $2$ and $\gcd(a^2+b^2, a^2-b^2)=1$ or $2 $. Progress We have $\gcd(a,b)=1\implies \exists u,v\in \mathbb Z$ such that $au+bv=1\implies a^2u'+bv'=1, u',v'\in \mathbb Z$. Let $\gcd(a+b, a-b)=d$. Then $\mid (a+b)x+(a-b)y, \forall x,y\in \mathbb Z$. How to show $\gcd(a+b, a-b)=1$ or $2$ and $\gcd(a^2+b^2, a^2-b^2)=1$ or $2 $. |
I know that the Series $\sum_{n=1}^\infty n \cdot x^n $ converges to $\frac{x}{(x-1)^2}$ but I'm not sure how to show it. I'm pretty sure that has been asked before, but I wasn't able to find anything... | How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method. In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$ |
I am putting a gate across my driveway which is 14ft between posts on either side. Its going to be wood and all 1x6 and 1x8 lumber to keep weight down. Each gate will be about 7ft long so I was thinking of putting a wheel at the end of both. I live in NH so Im sinking the post hole 4ft and the gate will be 4ft tall. Do I need to use a 6x6 and if so does the hole have to be 18in wide or can I do a 12in hole with a sonotube and concrete? | I have just built a 6 foot fence all the way around my property. To finish it offI need to build a driveway gate. The gate will be 15 feet wide and have two swing gate sections. I have used 4x4x8 foot posts buried approximately 26" and cemented. I was considering bolting two posts together and burying them at the same depth, but I am concerned that it still may not be enough support. The gates will have wheels on the bottom also. |
So I recently upgraded to 18.04 from 16.04 and whilst my experience has been good one thing kinda bugs me when using the file browser (Nautilus). When I'm in a directory and I wish to search in this directory Nautilus starts searching in my entire computer instead of just snapping to the first file/folder starting with the letter I typed. So the behaviour I'm looking for is basically this. Imagine I have a directory with 3 folders in it called foo, bar and baz. Then when I click the letter 'B' I simply want nautilus to snap to bar, instead of bringing up this search bar as it does now. Is this possible? | Before upgrading to Ubuntu 18.04 LTS, I was using Ubuntu 16.04.1 LTS. When I was in the file browser, I was able to access a file just by writing some letters; it just got selected and it was super fast. After upgrading, when I start typing a search is launched and it's a little bit slow. I prefer the old method. I tried searching on the internet but didn't know exactly what to type on the search bar. How can I disable this automatic search? Thank you |
Me and my dad enjoy playing Minecraft together, but he can't join my LAN world for some reason. But, I can still join his without issues. I've tried turning my firewall off, but it didn't work. What could be the root cause of this problem? | My LAN server won't let my cousin join me or me join my cousin. It won't show up on the multiplayer screen - it keeps saying "scanning for LAN servers" but it never finds it. I am at his house and we use different computers but it won't connect. How can I fix this? |
I've got a bunch of strings to browse and find there all words which contains "(at)" characters and then gather them in the array. Sometimes is a replacement of "@" sign. So let's say my goal would be to find something like this: "account(at)example.com". I tried this code: let gathering = myString.match(/(^|\.\s+)((at)[^.]*\.)/g;); but id does not work. How can I do it? I found a regex for finding email addresses in text: /([a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+)/gi) I think about something similar but unfortunately I can't just replace @ with (at) here. | I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps. It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps? |
I want to install MongoDB on Ubuntu. I am following the official instructions from . Now when I do: sudo apt-get update it's giving me: W: Duplicate sources.list entry http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages (/var/lib/apt/lists/downloads-distro.mongodb.org_repo_ubuntu-upstart_dists_dist_10gen_binary-amd64_Packages) W: Duplicate sources.list entry http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen i386 Packages (/var/lib/apt/lists/downloads-distro.mongodb.org_repo_ubuntu-upstart_dists_dist_10gen_binary-i386_Packages) W: You may want to run apt-get update to correct these problems I have also removed this entry manually but when I do: sudo apt-get update it again downloads the same files. I don't know what the issue is. I want to install the latest MongoDB. | I keep getting this warning whenever I try to run sudo apt-get update. W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ precise-updates/main i386 Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_precise-updates_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems Below is the output from /etc/apt/sources.list file: deb http://archive.ubuntu.com/ubuntu precise main restricted deb-src http://archive.ubuntu.com/ubuntu precise main restricted deb http://archive.ubuntu.com/ubuntu precise-updates main restricted deb-src http://archive.ubuntu.com/ubuntu precise-updates main restricted deb http://archive.ubuntu.com/ubuntu precise universe deb-src http://archive.ubuntu.com/ubuntu precise universe deb http://archive.ubuntu.com/ubuntu precise-updates universe deb-src http://archive.ubuntu.com/ubuntu precise-updates universe deb http://archive.ubuntu.com/ubuntu precise multiverse deb-src http://archive.ubuntu.com/ubuntu precise multiverse deb http://archive.ubuntu.com/ubuntu precise-updates multiverse deb-src http://archive.ubuntu.com/ubuntu precise-updates multiverse deb http://archive.ubuntu.com/ubuntu precise-security main restricted deb-src http://archive.ubuntu.com/ubuntu precise-security main restricted deb http://archive.ubuntu.com/ubuntu precise-security universe deb-src http://archive.ubuntu.com/ubuntu precise-security universe deb http://archive.ubuntu.com/ubuntu precise-security multiverse deb-src http://archive.ubuntu.com/ubuntu precise-security multiverse How do I fix it? |
After a lot of searching, I finally found the .pdf's for the elusive Griffiths script r character used in his ubiquitous undergraduate electrodynamics book. I made a simple package that allows me to use the figures as math characters: \NeedsTeXFormat{LaTeX2e}[1999/12/01] \ProvidesPackage{scriptr}[2014/06/18 Griffiths' Script r Character] \RequirePackage{graphicx} \def\rcurs{{\mbox{$\resizebox{.101in}{.08in}{\includegraphics{C:/Program Files/MiKTeX 2.9/tex/latex/scriptr/ScriptR.pdf}}$}}} \def\brcurs{{\mbox{$\resizebox{.104in}{.08in}{\includegraphics{C:/Program Files/MiKTeX 2.9/tex/latex/scriptr/BoldR.pdf}}$}}} \def\hrcurs{{\mbox{$\hat \brcurs$}}} There are two issues with it that I'd like to fix. I would like to make it so that the character automatically adjusts its size in the main body of a document depending on the size of the font. For example, in 12pt font it looks like this: In this case it looks as though it fits in perfectly with the rest of the text. However, in a smaller font size such as 10pt, it looks a little too big compared to its adjacent characters. In fact, it almost looks like capital letter: A similar problem persists whenever working with the character in math mode. When used with \frac, the character looks fine: But when used with \tfrac, the character looks far too big compared to what's in the numerator: What's the best way for me to make it behave more like an actual character in math mode? | I want to use a custom symbol in my document that is treated like any other letter or math symbol by LaTeX. I do not want to in order to create a new one but rather create one from scratch. Is there a way to just create the symbol using, say, Inkscape and tell LaTeX to print that when I call a specific macro? There is of course the possibility of using \includegraphics[height=1em], but I imagine that that is not a very effective approach. Can I let LaTeX use my symbol like any other math symbol? Do I have to (consisting of only one character) or is it possible to this in a simpler manner? |
When I browse questions on a site I'm registered for, I can see all questions - newest, featured, frequent, votes, active, and unanswered. But on sites I am not registered for, I can browse only newest questions. Sometimes I just want to see the highest voted questions on a site, and not ask or answer any. I recall I used to be able to do this (every developer's least favourite phrase), am I imagining things? | On the "Questions" page of each Stack Exchange site, there are links at the top to sort the questions by "newest", "frequent", "votes", "active", and "unanswered". At least that is what it looks like if I am logged in. If I am on a site that I don't have an account for, or if I am not logged in, the only one I see is "newest". This seems to have been done recently. I could swear I saw the other links, even when I was not logged in, until a few weeks ago, or maybe later than that. Why was this change made? |
Is there any way to convert a whole heap of .ogg files in about 30 folders in a folder containing those folders to .mp3 files and put them in another folder using the command ffmpeg? The previous methods I have tried all led to the same error: "*.ogg no such file or directory" If possible could you please tell me how? I cant find anything relating to this specific question. Edit: I've tried to edit the command and now it's giving me this error: (this goes for all of the files in the folder) /Users/Macbook/Downloads/Minecraft+Sound+Pack+1.13/step/wood6.ogg~/Downloads/Minecraft\ Sounds/step/wood6.mp3: No such file or directory I used this: $ for file in ~/Downloads/Minecraft+Sound+Pack+1.13/step/*.ogg > do > fullfilename=$(basename "${file}") > filename="${fullfilename%.*}" > ffmpeg -i "$file""~/Downloads/Minecraft\ Sounds/step/$filename.mp3" > done I think it's trying to link both directories together. | Any suggestions for a good, free audio converter for Mac? I used to use Max.app but it has long become abandonware and is now super buggy and crashy. I just need something I drop a couple (or 20 thousand) Apple Lossless files into and let it crank away making me some AAC compressed files or some MP3 or whatever. |
Why can't I use protected constructors outside the package for this piece of code: package code; public class Example{ protected Example(){} ... } Check.java package test; public class Check extends Example { void m1() { Example ex=new Example(); //compilation error } } Why do i get the error even though i have extended the class? Please explain EDIT: Compilation error: The constructor Example() is not visible | In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance? |
The series $$\sum_{k=1}^\infty \frac{1}{k^k}$$ clearly converges. Is it possible to compute its value analytically? | In the solution of the so-called , one of the key steps is to compute $$\int_0^1 x^n (\log x)^n~\mathrm dx$$ using the change of variables $x = \exp\left(-\frac{u}{n+1}\right)$ to obtain the Gamma function. This substitution to me, looks like it was pulled out of thin air. Can someone help me motivate it? How would I have thought of this substitution? |
I need to solve the following logical equivalence: (p ↔ q) ↔ ((p∧q)∨(¬p∧¬q)) I know i need to solve the problem in 2 parts, and i think i can do it with raa but im stuck. So if someone could give me some help it would be great. Thanks | I am working on a problem where I need to show the logical equivalence of two propositions. One is a biconditional: $p \leftrightarrow q$. And the other is this: $(p \land q) \lor (\lnot p \land \lnot q)$ I can get the biconditional down to this: $(\lnot p \lor q) \land (\lnot q \lor p)$ And I don't know how to change the second proposition. Can someone give me a place to start? |
I am looking for a right correlation metric to measure correlation between two vectors. The dimensionality of the vectors is around 100. The first vector has real values as the elements and the second vector has 0,1 values. Spearman rho is widely used as a correlation metric between two real-valued vectors, but my case is slightly different (0,1 values in one of the vectors). Whether Mann–Whitney U test is more appropriate in my case than Spearman Rho? I appreciate your help. | I would like to find the correlation between a continuous (dependent variable) and a categorical (nominal: gender, independent variable) variable. Continuous data is not normally distributed. Before, I had computed it using the Spearman's $\rho$. However, I have been told that it is not right. While searching on the internet, I found that the boxplot can provide an idea about how much they are associated; however, I was looking for a quantified value such as Pearson's product moment coefficient or Spearman's $\rho$. Can you please help me on how to do this? Or, inform on which method would be appropriate? Would Point Biserial Coefficient be the right option? |
I'm saving some SVG icons from Illustrator CC 2014 and when I give them to my dev he says can you make less CDATA. Does anyone know how? Thanks | I made an svg in Illustrator, but now I want to use it in a website/app but it's a huge size (around 10 MB) how can I decrease the size of it? My illustrator file is pretty big but that because I have some tracing elements underneath. The file also has a big artboard, but when I save should I delete my tracing elements, and decrease the artboard size? |
eg. txtfile is just [ sed -i 's/[/linux/' txtfile (this gives an error unbalanced brackets ([])) after running the command I wanted to replace [ to linux I tried \\ at the front, but I don't think it is correct and searched a while couldn't find anything useful. Thanks | Take the following script: #!/bin/sh sed 's/(127\.0\.1\.1)\s/\1/' [some file] If I try to run this in sh (dash here), it'll fail because of the parentheses, which need to be escaped. But I don't need to escape the backslashes themselves (between the octets, or in the \s or \1). What's the rule here? What about when I need to use {...} or [...]? Is there a list of what I do and don't need to escape? |
The following question is intended to be an example of a real conditional sentence ( first conditional)--not hypothetical. I would like to know whether to use "will" or "would" in this question: If a naive person falls victim to a trickster, would/will you blame the person for being naive or the trickster for being a criminal? As far as I understand, I should use "will," as "would" is only used for hypothetical situations. But, since my intention is not to talk about something that will happen in the future but something that is a possibility and can happen at any given time, I think that "will" is not the best choice in the example sentence above, is it? Or should I use "would" instead? | Consider the following sentence with a first conditional: If it rains tomorrow, I will go to the cinema. All the examples of first conditionals that I found use "will" instead of "would." Is it possible to replace "will" with "would" while retaining the same exact meaning, i.e., If it rains tomorrow, I would go to the cinema. Or, would I have to put the inflected verb in preterite form (as mentioned in ), like this: If it rained tomorrow, I would go to the cinema. [Edit 1: I clarified that I want to retain the same meaning among these examples.] [Edit 2: Corrected silly mistake where the first example was the same as the second example.] |
How to solve Exercise 2? How does embedding, I suppose in meaning of embedding defined before in the post linked as order-preserving ring homomorphism, $e:\mathbb{Q}\,{\rightarrow}\,K$, imply that for all ordered fields $K$ there exists a subfield of $K$ isomorphic to $\mathbb{Q}$? | I'm going through the first chapter in a text on real analysis, which contains preliminaries on ordered fields, the real numbers, etc. Supposedly I had learned about such things already, in calculus, but I thought it wouldn't hurt to go over it again. Up until the paragraph which is the subject of my question, everything is thoroughly proven and examples are provided. However the following excerpt just goes through facts, whose proof I cannot conceive: Although $\mathbb Q$ is an archimedean field, these properties cannot be used to define $\mathbb Q$ since $\\$ there are many Archimedean ordered fields. What distinguishes $\mathbb Q$ from the other $\\$Archimedean ordered fields is that $(\mathbb Q,<)$ is the $smallest$ ordered field in the following sense: $\\$ if $(X,\prec)$ is an ordered field, then $X$ contains a sub-field which is (field) isomorphic to $\mathbb Q$.$\\$ Furthermore such an isomorphism preserves the order relation. I've concatenated the paragraph a bit, so the text isn't idem from the book (if anyone wishes to know it's Phillips, An Introduction to Analysis and Integration Theory, Dover Publications). Also $\mathbb Q$ contains no proper subfields, and this can be verified by the apparently easy-to-prove fact that, if a field has characteristic zero, then it contains a subfield isomorphic to $\mathbb Q$. Then it remains to prove the preservation of order. I'm guessing that some concepts from abstract algebra or field theory would easily suffice, but at the moment such topics are a bit over my head, so all I can think of doing is actually constructing the isomorphism $\phi:\mathbb Q\to\hat{\mathbb Q}$, where $\hat{\mathbb Q}$ is a certain subfield of $X$ in such a way that field operations are preserved, but I really can't come up with anything. So the question is: how do I construct this isomorphism, or, if there's a better way of proving this, how is it done? Thanks for any help. Edit: Assume the existence of $(\mathbb Q,<)$ as an archimedean ordered field. |
Can someone maybe help me out and let me know how to set: ≠ in LaTeX? I am using Overleaf. I have tried \≠ but it did not work out. Thanks in advance. Greetings. | I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out? |
This is my first time to install Ubuntu version is 14.04 desktop. After installation on a virtual machine (Hyper V), It says to restart. IT will stop at: stopping early crypto disks ok Then it will stop here and it seems I have to shutdown the virtual machine to restart Ubuntu. I am not sure if my installation is complete or not. Thanks for any help. | I created a virtual machine to install ubuntu 14.04 on VirtualBox 4.2.12.*. I created virtual CD to install it with fixed-size virtual disk of 200GB. After successful installation, it restarted as usual. But after showing message of below, it hangs. Actually, I created virtual machines to install ubuntu at Virtual Box successfully several times. It's very easy. The installed ubuntu versions ranged from 9.10, 13.04 and even 14.04 before. I don't know why this time it hangs at restarting after successful installation. The only difference between this failure restart and previous successful ones is that the virtual disk is much larger, 200GB. It failed three times. * Deactivating swap... [OK] * Stopping remaining crypto disks... [OK] * Stopping early drypto disks... [OK] |
Evaluate $\displaystyle\lim_{x\to\infty}\frac{(\ln x)^n}x$, where $n\in\Bbb N$. I think $(\ln x)^n$ & $x$ is positive infinity when $x$ goes positive infinity so use a L'Hospital's theorem | Find $\displaystyle \lim_{x \to \infty} \dfrac{x}{(\log{x})^n}$. My book says that $\displaystyle \lim_{x \to \infty} \dfrac{(\log{x})^n}{x} = \lim_{y \to \infty} \dfrac{y^n}{e^y} = 0$, but I don't see how that is true. |
My husband and are i both Filipino citizen with a philippine passport and will travel home to philippines from Norway with almost 11hrs lay over in Incheon South Korea. We both have a valid Norwegian residence visa. Do we need a visa for us to go out from the airport?Thank you. | I'm a Filipino immigrant from USA about to visit home in December. I have a 14-hour lay over in Seoul, South Korea. Do I need a visa to leave the airport to do a little sightseeing? |
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