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First $\text{f}\left( 1 \right)=1$ beacause $\text{f}\left( a \right)^{\text{f}\left( 1 \right)}=\text{f}\left( a \cdot 1 \right)$, and $\log_{\text{f}\left( a \right)} \text{f}\left( a \right)^{\text{f}\left( 1 \right)} =\text{f}\left( 1 \right) \log_{\text{f}\left( a \right)} \text{f}\left( a \right) =1$ If $\text{f}\left( 2 \right) = c$ then $\text{f}\left( 2 \right)^{\text{f}\left( 2 \right)}=\text{f}\left( 4 \right)$ so $\text{f}\left( 4 \right)=c^c$ so there should be only one group of functions as a solution. So if $\overbrace{x^{\text{...}^{x}}}^{\text{n times}}=2$ then $\overbrace{{\text{f}\left( x \right)}^{\text{...}^{{\text{f}\left( x \right)}}}}^{\text{n times}}={\text{f}\left( 2 \right)}$ then the $n$th super root of $c={\text{f}\left( x \right)}$, $n=\text{slog}_x2$ so ${\text{f}\left( x \right)}$=the $\text{slog}_x2$ root of c. I am rather incompetent of my answer so if someone could look it over that would be great. Super roots and slogs | Consider the functional equation problem $$ f : \mathbb R \to \mathbb R \text , $$ $$ f \left( a ^ b \right) = f ( a) ^ { f ( b ) } \text , $$ when $ a , b \in \mathbb R $, $ a , b \ge 0 $. So far the only solution I have is the trivial $$ f ( x ) = x \text . $$ Does there exist any other possible solution? Even if the $ f $ doesn't have a closed form in terms of elementary functions, is there some way I could derive a series or an alternative expression for it? I tried to get a little more creative: $$ f ( w ) = f \left( w ^ { \frac 1 w } \right) ^ { f ( w ) } \text , $$ which nests deep into $$ f ( w ) = f \left( w ^ { \frac 1 w } \right) ^ { f \left( w ^ { \frac 1 w } \right) ^ { f \left( w ^ { \frac 1 w } \right) ^ \vdots } } \text , $$ which is equivalent to $$ \ln \big( f ( w ) \big) = \ln \bigg( f \left( w ^ { \frac 1 w } \right) \bigg) f ( w ) \text . $$ I was hoping to generate some sort of series using this. |
I've read several other answers on here, but I still don't understand. Why do both fission and fusion release energy? I know the masses drop, but then why do the masses drop on both? Fusion is taking two small nuclei, adding them together, and creating a bigger atom, why should this bigger atom have less energy? Is it because more of the mass gets stored in the strong force? Then what determines how much energy is released? The same goes for fission. A larger molecules being broke apart will approach a more stable max-energy-per-interaction form. This means that more energy should go into the bonds (I think) which would mean less mass, but still why does energy get released, and not just simply into the bonds? | I understand why fission generates large amounts of energy when the nucleus is split, but then why does fusion generate such large amounts of energy. If fission releases energy when some mass is lost as energy, then shouldn't the fusion process absorb energy to fuse nuclei together? I also am curious as to where the energy released from fusion comes from, while fission releases some of the energy of the strong nuclear force. |
I am looking for an easy video editor for Ubuntu 12.04. My needs are simple: make clips and upload them on sites (cut segments from a video file with frame to frame precision, convert into common formats, resize the file). Can anyone suggest one? | What video editing software would you recommend on Ubuntu (or Linux in general) and why? It can be for either beginners or experienced users. Please only place one piece of software per response and include details to what makes it great! |
I’m building a multiplayer hide-and-seek map, and I want to give seekers an instant-kill weapon named “Boop Stick” (don’t ask). /give @p leather_boots 1 0 {display:{Name:"Boop Stick",Lore:["Boop! You're dead."]},ench:[{sharpness:10}{knockback:10}]} (note that I’m using a placeholder item in the image) I keep getting errors like this: Line 1, Column 2 Missing '}' or object member name How do I fix this in a compact manner (ie easy to hide the command blocks)? | This question was recently split into different questions for each workaround. See meta posts for more information. Can you use NBT tags in commands? I’ve tried commands that normally work in Java Edition like: give @s minecraft:planks 30 1 {display:{Lore:["Wooden planks"]}} give @s stone_pickaxe{Unbreakable:1b} give @s item_frame{EntityTag:{Invisible:1b}} summon villager ~ ~ ~ {Offers:{Recipes:[{buy:{id:"emerald",Count:5b},sell:{id:"diamond_sword"}}]}} summon tnt ~ ~ ~ {Fuse:20s} |
I usually use chilkat library () develop only with windows. but this library have each library file for each platform, and today I have to do it cross platform. Example Windows x64 use win64.dll Windows x84 use win32.dll Linux x64 use linux64.so Linux x32 use linux32.so Max OSX use osx.jnilib This my source code for include chilkat library when use windows only. static { try { System.loadLibrary("lib/win64"); } catch (UnsatisfiedLinkError e) { try { System.loadLibrary("lib/win32"); } catch (UnsatisfiedLinkError e2) { System.err.println("Native code library failed to load.\n" + e2); System.exit(1); } } } And now I no idea. How include each library file on java application for cross platform ? Please guide best way to me. Thank you. Edit1: sorry for confusion. i know how find os.name on runtime. but this question i mean how include each library file for run each platform. | I would like to determine the operating system of the host that my Java program is running programmatically (for example: I would like to be able to load different properties based on whether I am on a Windows or Unix platform). What is the safest way to do this with 100% reliability? |
If some method requires an ICollection<T> as an argument, but I have only an IEnumerable<T> available: Is it better to convert this IEnumerable<T> to a IList<T> or is it better to convert it to an array T[] or shall I convert it to something else or is there no difference at all? The IEnumerable<T> is only required for this method call, so no further read/write/extend is required. | MyClass[] array; List<MyClass> list; What are the scenarios when one is preferable over the other? And why? |
This is something you can try in the interpreter, can anyone explain me why? Note: This problem is different from because my answers are not a little off, but way off and my question is about decimal, not about the built in float. from decimal import getcontext, Decimal a = Decimal(".110001"+"0"*17+"1"+"0"*95+"1"+"0"*599+"1"+"0"*4319+"1") b = Decimal(".220002"+"0"*17+"2"+"0"*95+"2"+"0"*599+"2"+"0"*4319+"2") b-a == a # Returns False while it should be True b-a-a # Returns Decimal('-1.000000000000000000000000000E-120') | Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004 Why do these inaccuracies happen? |
I often have a problem when lighting where to see the sharp edges on the mesh. This happens when I add any bump & when I use Lamp as a light source. And the darker the scene & the stronger bump, the more visible these edges, even when the object is smoothed. Please help with this problem. Because of this it's impossible to make quality works. | I wonder if this is a bug, or if I missed something... When a light hits tangentially convex surfaces with "smooth shading", the shadow on this surface seems to "partially ignore" the smoothness of the surface. Here is an example with a simple cylinder : On the left, a cylinder with "flat shading". Everything's ok. On the right, the same with "smooth". We can see an edge, bad shadowed. With or without the "Edge split" modifier, no matters, the edge is still there. The shader is a simple white diffuse shader with no texture nor displace. I have to add a subsurf modifier with at least 2 levels, which will insanely increase the vertex count... And I can't do that for my project. I hope someone already saw it, and have a little tip to share. Or if someone already know it's a bug, or a limit of the current Cycles renderer ? |
I am writing a book about illicit antiquities. Some of my resources spell this word, artefact; others, artifact. Is one right and the other wrong? | Is there any usage preference between artifact and artefact? My understanding was that an artifact was properly applied to physical, historical objects, while an artefact was more correct for more abstract, intangible, error-ish concepts, for example a compression artefact. However, the couple of I checked suggested that the difference was merely spelling, and that both were usable for both definitions. |
I have a method in java Public Object someMethod (String param) ( //some calculations Return Object ) I want to test the performance of this method ( how much time would it take to reach to db and return an object ) How can I do this? I don't have a main method because its a library. I use unit tests to check if it works. Help. | How do I get a method's execution time? Is there a Timer utility class for things like timing how long a task takes, etc? Most of the searches on Google return results for timers that schedule threads and tasks, which is not what I want. |
Ubuntu 14.04 LTS ending April 2019 then what next one needs to do and how. I would also like to know if we can directly jump to the higher release or upgrade step by step? If step by step then how to upgrade to the latest, please suggest. I would again like to opt for LTS. I am scared to do as grub should not get crashed.. Worth noting is i have dual boot with Win 7 ultimate. Regards, SHK | I am currently using Ubuntu 10.04. I know there is a 10.10 release, but can I upgrade directly to 11.04? Could you walk me through the steps please? |
Hello I'm new to the Linux system and would like to know if there is a code or application which opens a terminal that will tell me the lines of code being used. For example, If I were to open a folder or directory I would like to know the lines of code associated with it. | For example, I normally open mousepad (xfce equivalent of gedit) from the applications menu. However, I know that you can also do this in a terminal by typing mousepad. Following this example, what I want is whenever I open mousepad via GUI, a new line is written in a log file stating something like Sep 5 15:35:11 lucho@lucho:~$ mousepad. More in general, what I want is to log all GUI activities that are potentially do-able via command-line (like opening programs, changing permissions, modifying a system settings, etc) but written in its alternative command-line execution format. I want this in order to improve my knowledge of how to use the command-line (without going through the man pages). There are many things I do through the GUI which I don't do via command-line (some potentially automatable via a script or via keyboard shortcuts) and having this log file would be a good way to learn them. I'm aware of the existence of the syslog file in /var/log but that is not what I need. The Activity Log Manager app from Ubuntu repositories does not show command-line format, so far as I know. I need something like the .bash_history file that exist in my home folder but recording my GUI-based activities. |
This is my struct struct Entry { int a; int b; }; int main() { struct Entry data[260000]; //ok struct Entry data[262144]; //crash return 0; } I want to declare an array of Entry with the size is 2^18 (262144 elements) But I'm not able to do so. It seems like I go beyond the max. Is there another way to do this? | The following code is generating a stack overflow error for me int main(int argc, char* argv[]) { int sieve[2000000]; return 0; } How do I get around this? I am using Turbo C++ but would like to keep my code in C EDIT: Thanks for the advice. The code above was only for example, I actually declare the array in a function and not in sub main. Also, I needed the array to be initialized to zeros, so when I googled malloc, I discovered that calloc was perfect for my purposes. Malloc/calloc also has the advantage over allocating on the stack of allowing me to declare the size using a variable. |
Let $A$ be a nonzero commutative ring with $1$, and $n$ a positive integer. If $b_1,\ldots,b_n\in A^n$ generate $A^n$ as an $A$-module, is it true that $b_1,\ldots,b_n$ are linearly independent over $A$ (hence a basis)? I suspect this is true (It is true if $n=1$), but I can't seem to prove it. I guess an equivalent way of asking this question is: if a linear map $A^n\to A^n$ is surjective, is it necessarily injective? Any help is welcome! | Let $L$ be a finitely generated free module over a commutative ring $A$. Set $n=\operatorname{rank} L$. Let $x_1,\dots,x_m$ be generators of $L$. Then $m \ge n$? If $m = n$, then is $x_1,\dots,x_m$ a basis of $L$? |
The first question was to prove that $\gcd(F_{n+1},F_n) = 1$ So i tried to use it but with no success. any help or clue will appreciated thanks | Given the Fibonacci sequence $(F_1, F_2,F_3, ...)$ how do I prove that if $m|n$ then $F_m|F_n$? Can this be proven with mathematical induction? |
I have difficulties understanding what happens in MOS-FET-pinch-off: Take an N-MOSFET: Near the source the gate-bulk voltage is high enough to form an inversion layer. So we have electrons as majorities in the inversion layer. As the channel potential increases towards the drain, there is less voltage difference to form an inversion layer. Ultimately, close to the drain the difference is insufficient to form an inversion-layer. So we have a thin depleted p-layer or i-layer. I don't understand why this is still conducting. To me this looks like an N(source), N(channel), P(pinchoff-area), N(drain) structure. I would expect that to isolate or at least require an Uf between drain and source to conduct, which is not the case. What am I getting wrong ? I would be interested to see a band-model-diagram from source to drain for a MOSFET in pinch-off, but I have never found any, neither in a book nor on the web. | Here is what I have understood. Please correct me if I'm wrong. The depth of induced channel depends on the voltage V. Since the voltage across the gate and the path along the channel decreases from Vgs at the source to drain end to drain end, the channel is not uniform an is tapered. If the applied voltage Vds is increased to some value which causes the voltage between gate and drain end to be lesser than the threshold voltage, the channel is said to be pinched off. If the channel is pinched off, how does the drain current flow? It's given in the book that the MOSFET enters saturation region and will have a constant value of drain current. But I don't understand how does the current flow when the channel no longer exists at the drain end. |
Sometimes I have a mathematical formula using, e.g., \dot{x} in a footnote but I have difficulties in recognizing the effective presence of a dotted variable (my fault, I know... to quote the poet "That's not the electric light, my friend\\That's your vision growing dim."). Anyway, is it possible to use a heavier symbol for the dot that is usually used to indicate derivation w.r.t. time when used in a footnote? | I'm writing up some notes that will be displayed on an overhead projector. The standard time-derivative \dot{x} produces a dot that is hard to see. Does anyone know of a package or have a macro that produces a (nice looking) larger dot? Similarly with \ddot{x}. At the moment, I've been supplied with some ugly code that produces an ugly output: \def\dt#1{{\buildrel {\hbox{\LARGE . }} \over {#1}}} % dot-over \def\ddt#1{{\buildrel {\hbox{\LARGE ..}} \over {#1}}} % double dot |
I'm currently learning about IPv4 and subnetting. As far as I understand, if we want to create 4 small isolated networks with the size 50, we can use subnetting. If we subnet a Class-C IPv4 network(210.210.210.0) into 4 small networks with the same size (0~63, 64~127, 128~191, 192~255), these small networks are still essential belonged to the big logical network (210.210.210.0) even though we assign subnet masks to them. If I understand correctly, they can communicate with each other since they share the same network portion. So, in practice, how can we isolate these small networks? Thanks:) | This is a about IPv4 Subnets. Related: How does Subnetting Work, and How do you do it by hand or in your head? Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself. If I have a network, how do I figure out how to split it up? If I am given a netmask, how do I know what the network Range is for it? Sometimes there is a slash followed by a number, what is that number? Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different? Someone mentioned something about knowing binary for this? |
Let $\langle r_n\rangle$ be an enumeration of the set $\mathbb Q$ of rational numbers such that $r_n \neq r_m\,$ if $\,n\neq m.$ $$\text{Define}\; f: \mathbb R \to \mathbb R\;\text{by}\;\displaystyle f(x) = \sum_{r_n \leq x} 1/n^{2},\;x\in \mathbb R.$$ Prove that $f$ is continuous at each point of $\mathbb Q^c$ and discontinuous at each point of $\mathbb Q$. I find it difficult to prove especially the continuity on irrationals, I proved the discontinuity on a rational number in the following way is it correct? Let $ c \in \Bbb Q $ then $ c=r_n $ for some $n \in \Bbb N $ and Let $ \epsilon_0 = 1/n^{2} $ Let $\delta > 0 $ be arbitrary and let $ x \in (c-\delta. c+\delta)$ such that $x<c $ Then $|f(x)-f(c)|>1/n^{2}=\epsilon_0 $ How do prove that it is continuous on irrationals? | Sorry, I was having trouble giving the question because I can't figure out how to type in mathematical symbols. Let me try again: $\{q\}$ is an enumeration of the rational numbers, and $$f(x)=\sum_{q_n< x}\frac1{n^2}$$ for $x\in\Bbb R$. Or $f(x)=\sum(1/n^2)$, the index of summation $q_n< x$, and $q$ is an enumeration of the rational numbers. The goal is to prove that $f$ is continuous at each irrational and discontinuous at each irrational. I'm having trouble visualizing this series so I'm not sure why it is supposed to be different at irrational as opposed to a rational $x$ ... I think I need to use the epislon-delta definition of continuity but I'm not sure what epsilon to use. |
excuse me for asking such a generic question, but I can't phrase it better. I have seen code of this style fairly often, but have not yet used it. variable= someClass.someMethod(new someOtherClass(){ methodDeclaration(){ } }); If you don't know what I mean, the top answer could serve as an example: When is this used? Are there any examples of problems that can only be solved by such code? | What is the use of anonymous classes in Java? Can we say that usage of anonymous class is one of the advantages of Java? |
I have a label which is linked to an anchor. The problem is to find on which one of the four side of the label (which is a Rectangle) should be linked to the anchor. |label|<----[anchor] So I created a vector from the label center to the top right of the label (v1), a vector from the center to the bottom right (v2), to the top left (v3) and bottom left (v4). I also create a vector from the center of the label to my anchor (v). My problem is to find if v is between (v1,v2) , (v1,v3) , (v1, v4) or(v4, v2) so I can know from which side I should link my anchor. to calculate if a vector v is between v1 and v2 I use the following formula : (crossProduct v1, v >= 0 and crossProduct v, v2 >= 0) or (crossProduct v1, v <= 0 and crossProduct v, v2 <= 0) where crossProduct is calculated with the following formula: v1.y * v2.y - v1.x * v2.x However I'm not able to find the correct side of the rectangle. | If I have a point that is considered the origin and two lines that extend outwards infinitely to two other points, what is the best way to determine whether or not a fourth point resides on or within the angle created by those points? The process I'm currently using is to get the angle of all three lines that extend out from the origin and then check to see whether the third angle is within the range of the first two. Grid space is defined as Screen Space, that is, 2D Cartesian with the Y-Axis flipped so "up" is negative y and the origin is the upper left corner. |
Here is my MWE: \documentclass{article} \usepackage{amsmath} \usepackage{amsfonts} \usepackage[all]{xy} \makeatletter \newcommand{\test}{\xymatrix@M=-.3pt@=10pt} \newcommand{\testt}[2][1]{\ar@[|(1)]@#1{-}[#2]} \makeatother \begin{document} \begin{align*} &f=\test{ & \bullet \testt{dl} \testt{dr} \\ \bullet & & \circ } &g=\test{ & & \bullet \testt{dl}\testt{d}\testt{dr}\\ & \bullet & \bullet \testt{d} & \bullet \testt{d}\\ & & \circ & \circ } \end{align*} \end{document} Please help!!!!! related to this but solution not working | I have a problem compiling the following document. First, I have a file macros.sty that consists of : \newcommand{\test}{ \xymatrix@R=0mm{x} } Then, I have an auxiliary file out.aux that consists of : \test Finally, the main file is : \documentclass{article} \usepackage[all]{xy} \usepackage{macros} \begin{document} \input{out.aux} \end{document} The error message is : ./out.aux:1: Undefined control sequence. \xymatrix@R ->\Addop@@ \xymatrixrowsep@ \dimen@ii Note that if you remove the R=0mm, the problem no longer holds. Is that a bug ? It is very strange because I remember to have already used a command similar to \test in an input file without any problem. Does it come from my distribution ? Thank you :) |
I was going through IEnumerable and IEnumerator , but could not get one point clearly..if we have foreach, then why do we need this two interfaces? Is there any scenario where we have to use interfaces.If yes, then can somebody explain with an example. Any suggestions and remarks are welcome. Thanks. | Can anyone explain IEnumerable and IEnumerator to me? For example, when to use it over foreach? what's the difference between IEnumerable and IEnumerator? Why do we need to use it? |
In Avengers: Endgame, if Thanos from 2014 was dusted in 2023 by Iron Man's snap, then how did the Thanos other 'snap' in 2018? Does this imply that there is a branch reality where they never bring back everyone with Professor Hulk's snap. | Spoilers ahead! Plot points are revealed here, I'll put the deeper plot points in spoiler boxes. Time travel features heavily in the plot of Endgame. Correct me if I'm wrong, but the MCU seems to subscribe to a multiverse of sorts. This makes any alterations to the past fine, and the "present" people making those changes return to the future they left from unaffected. So, the plan is: pop into the past to gather the Infinity Stones, wield them to perform a reverse snap, then pop them right back where you found them as if they'd never left at all. This plan succeeds. However, as a result, the pre-snap Thanos journeys into the future to protect the job he has yet to do, and is defeated in the process. This means that, although the Stones are placed back in their respective times (the Cap's last job before retiring), there's now a universe short of Thanos. So, my question: is there now a universe out there in which the snap never occurred as well as several of the Avenger's adventures (anything after 2014, I think that's where Thanos travelled from), while at the same time there is a universe (the one we see in the films) in which all of the events of the MCU films transpired? A further point, we're told that traveling back to kill a baby Thanos wouldn't work because they'd still be in the timeline they left from upon return (the snap one), while the other timeline would exist to no benefit of their own. This is why the mission was never about killing a pre-snap Thanos - your own past is unchangeable, the snap is locked in. Therefore, the Thanos that travelled to 2023 is forever locked in to travelling to that point and being defeated, meaning the time he came from must no longer have him. This could also explain how the universe that we watch through the movies has a Gamora now. Because she came from a timeline in which Thanos never sacrifices her, she can be alive (remember, we're told that there's no way to reverse the sacrifice made to retrieve the Soul Stone - the only way she can be alive is if she's from a universe where she was never sacrificed (i.e. no Thanos after 2014)). |
I posted a while back, and I think I may not have made myself clear or shown what I got so far. So let me post this question again with more information and clarification. I have a sequence of polynomials $Q_k(x, y)$, $k\geq 1$ defined recursively as follows: $Q_1=x$. There is a sequence of polynomials $p_j(y)$ of degree $j$ such that $Q_{2m}$ is of the form \begin{eqnarray}\frac{p_{0}(y)}{(2m)!}x^{2m}+\frac{p_{1}(y)}{(2m-2)!}x^{2m-2}+\cdots+\frac{p_{m-1}(y)}{2!}x^2+p_{m}(y)\end{eqnarray} and $Q_{2m+1}$ \begin{eqnarray} \frac{p_{0}(y)}{(2m+1)!}x^{2m+1}+\frac{p_{1}(y)}{(2m-1)!}x^{2m-1}+\cdots+\frac{p_{m-1}(y)}{6}x^3+p_{m}(y)x \end{eqnarray} $Q_k(k+1-2i, k+1)$ as a polynomial in $i$ has roots $1, 2, \cdots, k$. Find a general formula of $Q_k(x, y)$. The following are the first 4 polynomials in the sequence: \begin{align*} Q_1&=x\\ Q_2&=\frac{x^2}{2}-\frac{y}{6}\\ Q_3&=\frac{x^3-xy}{6}\\ Q_4&=\frac{x^4-2x^2y}{24}+\frac{y(5y+2)}{360} \end{align*} In fact, it suffices to find the sequence of polynomials $p_j(y)$. Here's what I've got so far. By condition (2) and (3), we have \begin{eqnarray} \sum_{j=0}^m \frac{p_j(2m+1)}{(2m-2j)!}(2i-2m-1)^{2m-2j}=\frac{2^{2m}}{(2m)!}(i-1)(i-2)\cdots(i-2m) \end{eqnarray} If we let $m=j+k$, differentiate both sides with respect to $i$ $2k$ times and put $\displaystyle i=\frac{2j+2k+1}{2}$, we have \begin{eqnarray} p_j(2j+2k+1)=\left.\frac{d^{2k}}{di^{2k}}\right|_{i=\frac{2j+2k+1}{2}}\frac{2^{2j}}{(2(j+k))!}(i-1)(i-2)\cdots(i-2(j+k)) \end{eqnarray} Letting $k=0, 1, \cdots, j$, we get the $j+1$ values taken by $p_j$ at $2j+1, 2j+3, \cdots, 4j+1$. $p_j$ then can be computed using Lagrangian interpolation. It seems to me that, though the above algorithm can be implemented on a computer to get a few polynomials in the sequence, it does not yield directly a general formula I want. Is there another better way to go about getting a general formula? Edit: The first 5 members in the polynomial sequence $p_j(y)$ are the following: \begin{align*} p_0(y)&=1\\ p_1(y)&=-\frac{y}{6}\\ p_2(y)&=\frac{y(5y+2)}{360}\\ p_3(y)&=-\frac{y(35y^2+42y+16)}{45360}\\ p_4(y)&=\frac{y(5y+4)(35y^2+56y+36)}{5443200} \end{align*} | I have a sequence of polynomials $Q_k(x, y)$, $k\geq 1$ defined recursively as follows: $Q_1=x$. There is a sequence of polynomials $p_j(y)$ of degree $j$ such that $Q_{2m}$ is of the form \begin{eqnarray}\frac{p_{0}(y)}{(2m)!}x^{2m}+\frac{p_{1}(y)}{(2m-2)!}x^{2m-2}+\cdots+\frac{p_{m-1}(y)}{2!}x^2+p_{m}(y)\end{eqnarray} and $Q_{2m+1}$ \begin{eqnarray} \frac{p_{0}(y)}{(2m+1)!}x^{2m+1}+\frac{p_{1}(y)}{(2m-1)!}x^{2m-1}+\cdots+\frac{p_{m-1}(y)}{6}x^3+p_{m}(y)x \end{eqnarray} $Q_k(k+1-2i, k+1)$ as a polynomial in $i$ has roots $1, 2, \cdots, k$. Find a general formula of $Q_k(x, y)$. The following are the first 4 polynomials in the sequence: \begin{align*} Q_1&=x\\ Q_2&=\frac{x^2}{2}-\frac{y}{6}\\ Q_3&=\frac{x^3-xy}{6}\\ Q_4&=\frac{x^4-2x^2y}{24}+\frac{y(5y+2)}{360} \end{align*} In fact, it suffices to find the sequence of polynomials $p_j(y)$. Here's what I've got so far. By condition (2) and (3), we have \begin{eqnarray} \sum_{j=0}^m \frac{p_j(2m+1)}{(2m-2j)!}(2i-2m-1)^{2m-2j}=\frac{2^{2m}}{(2m)!}(i-1)(i-2)\cdots(i-2m) \end{eqnarray} If we let $m=j+k$, differentiate both sides with respect to $i$ $2k$ times and put $\displaystyle i=\frac{2j+2k+1}{2}$, we have \begin{eqnarray} p_j(2j+2k+1)=\left.\frac{d^{2k}}{di^{2k}}\right|_{i=\frac{2j+2k+1}{2}}\frac{2^{2j}}{(2(j+k))!}(i-1)(i-2)\cdots(i-2(j+k)) \end{eqnarray} Letting $k=0, 1, \cdots, j$, we get the $j+1$ values taken by $p_j$ at $2j+1, 2j+3, \cdots, 4j+1$. $p_j$ then can be computed using Lagrangian interpolation. It seems to me that, though the above algorithm can be implemented on a computer to get a few polynomials in the sequence, it does not yield directly a general formula I want. Is there another better way to go about getting a general formula? Edit: The first 6 members in the polynomial sequence $p_j(y)$ are the following: \begin{align*} p_0(y)&=1\\ p_1(y)&=-\frac{y}{6}\\ p_2(y)&=\frac{y(5y+2)}{360}\\ p_3(y)&=-\frac{y(35y^2+42y+16)}{45360}\\ p_4(y)&=\frac{y(5y+4)(35y^2+56y+36)}{5443200}\\ p_5(y)&=-\frac{y(385y^4+1540y^3+2684y^2+2288y+768)}{359251200} \end{align*} It is noteworthy that the denominators happen to be the first 6 numbers in , as pointed out by Solomonoff's Secret. |
I am having global class "with sharing" and invocable method in that, I am aware that Process Builder runs in system mode, however I am having confusion around the class which is getting called from Process builder will also run in system mode? The reason I am asking this is because, security scanner suggested me to add CRUD checks in this class, however I want to run all logic in system context, so I am thinking to make it as false positive(I will be updating it to without sharing) Please advise. | I have a basic class with no sharing keyword as I want it to inherit the permissions from callee. What would the context be? I assume it should run as system (aka without sharing) context, but what I am seeing is opposite. I am getting security exceptions that I shouldn't and fixes by upgrading the class to without sharing. Is this expected behaviour? |
I have something like this in a file testtt: {It captures this! } // question: 2572410 name: Question 2 ::Question 2::[html] Is it going to be -40 tomorrow? { It can't capture this!!! why? } when I do: grep -o '{\([^}]*\)}' testttt It can't capture the multi-line braces. Any help to modify it in way that it could capture both would be apppreciated! PS. I have also tested the given solution from: and it gives the following error: grep: unescaped ^ or $ not supported with -Pz You can find the text file of the output and file contents | To be precise Some text begin Some text goes here. end Some more text and I want to extract entire block that starts from "begin" till "end". with awk we can do like awk '/begin/,/end/' text. How to do with grep? |
want to run junit test cases sequentially and parallel also. some test cases are independent so those test cases are need to run sequentially but some test cases are not dependent they have to run parallel. is this possible through junit ? if yes how it is possible ? | I'm using JUnit 4.4 and Maven and I have a large number of long-running integration tests. When it comes to parallelizing test suites there are a few solutions that allow me to run each test method in a single test-class in parallel. But all of these require that I change the tests in one way or another. I really think it would be a much cleaner solution to run X different test classes in X threads in parallel. I have hundreds of tests so I don't really care about threading individual test-classes. Is there any way to do this? |
There is a sentence about "statement" that I can't understand in C Primer Plus by Stephen Prata. In Chapter 5, there is a section which explains difference between statement and expression. The author explains statement as follows: Statements Statements are the primary building blocks of a program. A program is a series of statements with some necessary punctuation. A statement is a complete instruction to the computer. In C, statements are indicated by a semicolon at the end. Therefore, legs = 4 is just an expression (which could be part of a larger expression), but legs = 4; is a statement. And then the author gives an example: Although a statement (or, at least, a sensible statement) is a complete instruction, not all complete instructions are statements. Consider the following statement: x = 6 + (y = 5); In it, the subexpression y = 5 is a complete instruction, but it is only part of the statement. Because a complete instruction is not necessarily a statement, a semicolon is needed to identify instructions that truly are statements. The authors says that "y=5"is a complete instruction but as she mentioned above isn't this just an expression, not a complete statement? | I'm asking with regards to c#, but I assume its the same in most other languages. Does anyone have a good definition of expressions and statements and what the differences are? |
N-PLURAL represents plural noun according to the explanation in the Collins COBUILD dictionary. Can I interpret it as a noun that is countable but unable to be used in singular form and only able to be used in plural form? | N-SING represents singular noun according to the explanation in the Collins COBUILD dictionary. Can I interpret it as a noun that is countable but unable to be used in plural form and only able to be used in singular form? |
I have seen people use passwd -l "$USERNAME" , But the linux man page does not explain what the -l option is for. What does it do ? | Let's say I create a user named "bogus" using the adduser command. How can I make sure this user will NOT be a viable login option, without disabling the account. In short, I want the account to be accessible via su - bogus, but I do not want it to be accessible via a regular login prompt. Searching around, it seems I need to disable that user's password, but doing passwd -d bogus didn't help. In fact, it made things worse, because I could now login to bogus without even typing a password. Is there a way to disable regular logins for a given a account? Note: Just to be clear, I know how to remove a user from the menu options of graphical login screens such as gdm, but these methods simply hide the account without actually disabling login. I'm looking for a way to disable regular login completely, text-mode included. |
on boot iptables blah --blah iptables blah --blah service myservice /system/bin/myarm64binary --config /path/to/conf.cfg class main user root According to the documentation: / init.rc is the most important. RC file. It is loaded by init process at the time of initialization. It is mainly responsible for system initialization. It will import / init.${ro.hardware}.rc, which is the main. RC file provided by system-level core vendors. When the mount_all statement is executed, the init process loads all files in the /{system,vendor,odm}/etc/init/ directory, which will serve Actions and Services when the file system is mounted. Is there something I'm missing? service list does not list my app and iptables not appended. Even if I test-edit init.rc and import my .rc directly it still does nothing. | I have an executable build from a ndk-build program. I want to run it on a rooted Android device. How much is the possibility that Android will kill my executable? Using adb shell, I am able to execute my executable using following commands: adb push executable /sdcard adb shell device:/ $ su device:/ # cd /system device:/system # mount -o rw,remount /system device:/system # mv /sdcard/executable . device:/system # ./executable My requirement is to run this executable on device boot. I have tried following: Write ./executable in init.rc. On reboot init.rc reset to its original contents. I figured out that Magisk done this. Write commands in /system/etc/init/bootstat.rc ./executable service custom /system/executable on boot ./system/dhandler/diag_revealer None of the above thing is working. |
Below is my object in JavaScript, how can i calculate the length of it. var treeObj = { 1: ['96636736','10'], 2 : ['96636734','20'], 3 : ['96636731','45'] }; treeObj .length is not working. any help would be appreciated. Thanks. | I have a JavaScript object. Is there a built-in or accepted best practice way to get the length of this object? const myObject = new Object(); myObject["firstname"] = "Gareth"; myObject["lastname"] = "Simpson"; myObject["age"] = 21; |
I am really struggling to find the solution to this problem. I would really appreciate It if you guys could put the script in nano. | If I check with , I can see my public IP. Is there something on the Ubuntu command-line which will yield me the same answer? |
Back Story: I built a new computer, using the MSI Z490 A Pro motherboard. It comes with a RTL8125 2.5G Ethernet Controller. I decided to install Ubuntu 20.04 for this build. This distro doesn't seem to come with necesssary driver for this controller. I don't have wifi either. If part of solution is tethering with bluetooth I could give that a shot, but I would prefer to learn with driver from usb stick if possible. I have no Linux or programming experience, except a bit of front-end web dev., so you're dealing with a novice, but I started to read and learn about Ubuntu and linux, so far I got the thing installed and I'm getting to know commands, command prompt, terminal in general. I believe I would know how to get it going with clear step-by-step instructions, I have a generally good grasp of the basics of how its structured (if I qualify to say that, lol). Typing in terminal lspci -knn | grep Eth -A3 I get the name of my Ethernet controller, RTL8125 2.5G ...and also it shows at bottom: kernel modules: r8169. Typing in terminal: sudo lshw -C network says: network unclaimed and shows Ethernet Controller RTL8125 info. Here is the link to realtek website: On the Realtek website there is a driver for RTL8125 for linux. I tried following instructions, however they assume people are experts, or info ommited. But I got stuck on third step.. First step: unpack the tarball, Second step: "Change to the directory: # cd r8125-8.aaa.bb" Third step: If you are running the target kernel, then you should be able to do: # ./autorun.sh So I decided to make a new directory and put all content of driver(r8125-8.aaa.bb) in it. New directory path: ~/Downloads/Drivers Then I used chmod 777 in terminal to give executive permissions to all files from driver folder. Then I tried to do third step and didn't seem to work. Is there something I need to do with NetworkManager directory? Should I make a new kernel module somehow? What about dkms? What does that have to do with this problem? | So I did a fresh install of Ubuntu 20.04 on a computer with the new RTL8125B Realtek network card and I cannot get the network to work. I was very suprised since this is supposed to be the new feature of the 5.4 kernel (I have 5.4.0-26-generic installed). Does anyone have any idea on how to get it working? Thank you. $ lspci -knn | grep Eth -A3 06:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 04) Subsystem: ASUSTeK Computer Inc. RTL8125 2.5GbE Controller [1043:87d7] Kernel modules: r8169 07:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] [1002:67df] (rev e7) $ dmesg | grep -i r8169 [ 0.911236] r8169 0000:06:00.0: unknown chip XID 641 |
Sorry for such a newbie question. I tried google but can't find anything similar. I'm using Illustrator CS6 so I don't have CC's rounded corner tool. I tried Effects > Stylize > Round Corners but it doesn't work. Here's what happens: (as you can see it distorts it) I also tried applying a stroke to circle and removing the bottom half of circle then applying rounded caps to stroke but I don't like the final result. Here's what I want to do. This is what i have created by manually adjusting the corners using the pen tool but it looks pretty bad. | I have the following figure in which I need to make a fillet to each its corners: Is there some tool to avoid doing this manually? I tried the Effect > Stylize > Round Corners tool but it apply the roundness also to the circles. I'm using the CS6 version of Adobe Illustrator. |
Here's the integral: $$\int_{1}^{5}{\frac{\sqrt{x}}{\sqrt{6-x}+\sqrt{x}}dx}$$ tried rationalising the function: $$\frac{\sqrt{x\left( 6-x \right)}-x}{6-2x}$$ which doesn't get me anywhere with substitution or integration by parts I would appreciate if someone were to help me through hints/techniques (besides numerical methods). | Evaluate: $$\int_{1}^{2011} \frac{\sqrt{x}}{\sqrt{2012 - x} + \sqrt{x}}dx$$ Using real methods only. I am not sure what to do. I tried finding a power series, which was too ugly. I just need some hints, not an answer to do this integral, this is from the MIT Integration bee 2012. |
Since yesterday's downtime, my notification bar indicates one unread message, always. Opening the dropdown shows that all messages are read. The indicator resets when the dropdown closes then, but reappears when the next page is loaded. Notifications about reputation changes are apparently not visible on the bar anymore. Logging out and back in has not had any effect, nor did a switch to a different browser. Have you guys faced similar issues? | This was asked before too. . Currently I am facing the issue of appearance of reputation notification in above toolbar. I can see the reputation notification, for every page refresh even after clicking and viewing the notification. current browser: Chrome Version 36.0.1985.143 m |
$|G| = pqr$ with $p$, $q$ and $r$ distinct primes. Show G is not simple. I know this might have been asked and answered before. I just wanted someone to tell me if my argument is OK: Let $|G| = pqr$, and assume $p < q < r$. We have at least one Sylow-$q$ subgroup (call it $Q$) and at least another Sylow-$r$ subgroup (call it $R$). Consider the subgroup $K = $ $<Q, R>$. Now $K$ is not the whole group because there is no element of order $p$ in there. Further, $|K|$ must equal $qr$ because nothing smaller is possible by Lagrange's theorem. Therefore [G : K] = p, which is the smallest prime dividing G. Hence by a standard theorem (for instance, see corollary 4.5, p. 44, Isaacs' Algebra), K must be normal. Hence $G$ is not simple. Thanks! WH | Here's a question I've been asked; Given distinct primes $p,q,r$, show that any group $G$ of order $pqr$ is not simple. So far, my idea has been to individually check each possible proper subgroup, since by Lagrange there are only $$\dbinom{3}{2} + \dbinom{3}{1} + 1$$ of them, and show that at least one of them other than the trivial group is normal. Surely there is a smarter way, since generalizing this approach wouldn't work so well if I wanted to show similar results for groups who's order is a product of $n$ distinct primes. Is there some other approach? Thanks for any insights |
I`ve got closed curve in the center of my mesh. I want to vertices which highlighted by yellow have circle-form, not the form like on the photo. Can i smooth them to circle-form? | As the title says, I'm trying to extrude an irregular face into a normal cylinder. There are some pics below to better describe what I want to achieve The tip of the sculpture is round, while the bottom is pretty splash-y shaped, and as it ascends it becomes more and more round So, is there a way to do something like that? thanks |
My current requirement is to convert LWC page into PDF format. I tried built in 're-render as PDF' option though VF page. But it does not look good & i am not able to add Graphs/Charts into it. Does anyone know to any way to convert LWC/Aura component to PDF format with graphs/chart included? Please help!! | I use LWC components in Customer Community. There is datatable component with records and I implemented the function to export selected records in .csv and .pdf. csv works fine, but I experience the next issue when downloading the file as pdf: Here is the code I use to create and download the file: main.js handleExportAction(evt) { const selectedFormat = evt.detail.value; try { let _file; let _type; switch (selectedFormat) { case 'csv': _file = parseToCSV(this.columns, this.selectedRows); _type = 'text/html'; break; case 'pdf': _file = parseToPDF(this.columns, this.selectedRows); _type = 'application/pdf'; break; default: _file = undefined; _type = undefined; } downloadDataAsFile('Subscription Overview.' + selectedFormat, _type, _file); } catch(e) { console.error(e); } } service.js - parse&donwloadFile functions const parseToPDF = (tableCols, rows) => { let cols = []; tableCols.filter(el => cols.push('<th>' + el.label)); let fileData = '<html><head>'; fileData += '<title>Subscription Overview</title>'; fileData += '<body><table>'; fileData += '<tr>'; fileData += cols.map(col => col).join('</th>') + '</th>'; fileData += '</tr>'; fileData += '<tr>'; fileData += '<td>Test Data</td>'; fileData += '</tr>'; fileData += '</body></html>'; console.log('file: ' + fileData); return fileData; }; const downloadDataAsFile = (name, type, data) => { var file = new Blob([data], { type: type }); if (window.navigator.msSaveOrOpenBlob) { // IE10+ window.navigator.msSaveOrOpenBlob(file, filename); } else { // Others var a = document.createElement("a"), url = URL.createObjectURL(file); a.href = url; a.download = name; document.body.appendChild(a); a.click(); setTimeout(function () { document.body.removeChild(a); window.URL.revokeObjectURL(url); }, 0); } }; The body (fileData) variable is for testing purposes, I tried other options but the result was the same. Probably the issue is in contentType which I set as application/pdf? I did not find any limitations related to creating pdf files with js. Did someone experienced this issue before? Thanks in advance. |
My daughter logged in to her Gmail account and it seems to be the default; when I open Gmail, hers is first choice, then mine; she lives in another state and only used her account here once. How do I remove her account as an option every time I log in? | I typically use 2 Google accounts simultaneously in my browser. So whenever I fire up any Google service like Google Maps or YouTube or Google Search, it uses one of the accounts. The problem is that I don't want that account to be used and no matter how many times I switch the account for these services, they seem to default to same account. Is there any way to tell Google to use a particular account for all Google services by default? I am not talking about using Google account to sign in to third party websites. I am talking only about Google's own services. I am using Chrome if anyone is going to suggest client-side solution. |
Is there a strict rule in the UK on how to write long figures? If so, which one is it? For example, if I need to write long numbers and follow the UK standard, which figure is correct? 10 000 000 000 people (ten billion people) or 10,000,000,000 people ? Same example but with another figure: which one is correct? £1 000 000,85 or £1,000,000.85 | Is it necessary to use comma in a big number? For example, if anyone writes one million four hundred thousand and two as 1400002 instead of 1,400,002 on answer sheet of listening section of IELTS test, will it be considered incorrect? Thanks in advance. |
I have written a shell script which in turn calls another script, but the second one prompts for password. I want to supply the password and pass the prompt without user begin notified. Here is my script: su - s3 -c "su.sh" I trided : su - s3 -c "echo pass | su.sh" But I got an error: standard in must be a tty Updated: The screenshot of commands. I also tired : su - s3 -c "echo mypass|sudo -S su.sh" but another error comes up: sudo: sorry, you must have a tty to run sudo su.sh commands: if [ ! -n "$IS_WINDOWS" ] then /bin/su root -c "...." fi | I have a script run from a non-privileged users' crontab that invokes some commands using sudo. Except it doesn't. The script runs fine but the sudo'ed commands silently fail. The script runs perfectly from a shell as the user in question. Sudo does not require a password. The user in question has (root) NOPASSWD: ALL access granted in /etc/sudoers. Cron is running and executing the script. Adding a simple date > /tmp/log produces output at the right time. It's not a permissions problem. Again the script does get executed, just not the sudo'ed commands. It's not a path problem. Running env from inside the script being run shows the correct $PATH variable that includes the path to sudo. Running it using a full path doesn't help. The command being executed is being given the full path name. Trying to capture the output of the sudo command including STDERR doesn't show anything useful. Adding sudo echo test 2>&1 > /tmp/log to the script produces a blank log. The sudo binary itself executes fine and recognizes that it has permissions even when run from cron inside the script. Adding sudo -l > /tmp/log to the script produces the output: User ec2-user may run the following commands on this host: (root) NOPASSWD: ALL Examining the exit code of the command using $? shows it is returning an error (exit code: 1), but no error seems to be produced. A command as simple as /usr/bin/sudo /bin/echo test returns the same error code. What else could be going on? This is a recently created virtual machine running the latest Amazon Linux AMI. The crontab belongs to the user ec2-user and the sudoers file is the distribution default. |
I am solving a problem on binary classification. The Wikipedia of the Rand index states that for binary classification the Rand index is equivalent to the accuracy: $$ R I=\frac{T P+T N}{T P+F P+F N+T N} $$ Is this statement right?. I am solving a binary classification problem. I have computed the accuracy and the rand index using sklearn.metrics.rand_score. Nevertheless they lead to a different result. I have found a similar question in but it is not the same case since I have checked that the accuracy doesn't correspond to the Rand neither for the clustering nor for the permutation of the clustering. | I'm very confused, when I read on the wikipedia "From a mathematical standpoint, Rand index is related to the accuracy, but is applicable even when class labels are not used." and But when I use in R the rand.index function from fossil package and the Accuracy function from MLmetrics it doesn't give the same answer > Accuracy(predicted, real) [1] 0.8266667 > rand.index(predicted,real) [1] 0.7114989 Please can someone explain to me the difference between these two and which one should I use? NB:I use the k-medoids clustering algorithm (function pam from cluster package) |
Prove the following proposition: Suppose $a,b$ are fixed integers. Then $\{ ax+by\mid x,y\in\mathbb Z\} = \{ n(a,b) \mid n\in\mathbb Z\}$. | I have the following problem: Let $a, b \in\mathbb{Z}$. Show that $\,\{ ax + by\ :\ x, y \in \mathbb{Z}\} = \{ n \gcd(a,b)\ :\ n\in \mathbb{Z} \}$ I understand that the Bezout's lemma says that $gcd(a,b) = ax +by$, so Im not really how you would go about proving the above, it doesn't really make sense to me. Any help is appreciated1 |
I have this three tables: CREATE TABLE userTypeA ( id VARCHAR (256) PRIMARY KEY, nickname VARCHAR (256) NOT NULL, password VARCHAR(70) NOT NULL DEFAULT '123456' --AND MORE OTHER ATTRIBUTTES DIFFERENT FROM OTHER USERTYPES ); CREATE TABLE userTypeB ( id VARCHAR (256) PRIMARY KEY , nickname VARCHAR (256) NOT NULL, password VARCHAR(70) NOT NULL DEFAULT '123456' --AND MORE OTHER ATTRIBUTTES DIFFERENT FROM OTHER USERTYPES ); CREATE TABLE userTypeC ( id VARCHAR (256) PRIMARY KEY , nickname VARCHAR (256) NOT NULL, password VARCHAR(70) NOT NULL DEFAULT '123456' --AND MORE OTHER ATTRIBUTTES DIFFERENT FROM OTHER USERTYPES ); Now, my idea was creating a table which has a foreign key that can reference the id of one of the three tables (userTypeA, userTypeB, userTypeC). In occasions it will reference table userTypeA, on other occasions it will reference table userTypeB and in others userTypeC. I tried this, but it seems to fail: CREATE TABLE account ( account_id VARCHAR (256), user_id VARCHAR (256), PRIMARY KEY (account_id), CONSTRAINT accounts_users_fk1 FOREIGN KEY (user_id) REFERENCES userTypeA (id), CONSTRAINT accounts_users_fk2 FOREIGN KEY (user_id) REFERENCES userTypeB (id), CONSTRAINT accounts_users_fk3 FOREIGN KEY (user_id) REFERENCES userTypeC (id), ); I've been looking for some examples but none looked like mine. Do you know any way to be able to reference one of the three tables with a single foreign key, or should I create different tables and structure them differently? | Well here's my problem I have three tables; regions, countries, states. Countries can be inside of regions, states can be inside of regions. Regions are the top of the food chain. Now I'm adding a popular_areas table with two columns; region_id and popular_place_id. Is it possible to make popular_place_id be a foreign key to either countries OR states. I'm probably going to have to add a popular_place_type column to determine whether the id is describing a country or state either way. |
I am new to linux and have been trying for a day now to get it installed, which i have, but it will not boot. When I turn on my pc, it boots straight to windows. I'm not sure what to do to fix this. I have tried using boot repair disk and this is what it came up with. . Any and all help would be greatly appreciated. Edit: I installed ubuntu 15.04 | I have an Ubuntu 12.04 / Windows 7 dual boot. After installing Ubuntu my computer reboots straight to Windows. There is no option to boot Ubuntu. Specs: OS: Windows 7 Home Premium CPU: Intel i5 2500k mobo: ASUS P8Z68-V Pro GPU: GeForce GTX 570 SSD: Corsair 120GB (Windows 7) HDD: WD 1TB I select the USB drive in the BIOS and boot to it and choose install. I select to manually configure partitions, partition the 200 GB of unallocated space on my 1 TB HDD into 16 GB swap file, 30 GB / ext4, and 154 GB /home ext4. I made sure that the bootloader is installed on the Corsair 120GB SSD (where the Windows boot is) and the installation goes smoothly. When I reboot after the install it runs through the BIOS straight into Windows. I have tried upwards of a dozen times and I have also tried with Linux Mint. I have also redownloaded the ISO and used two different programs to create the live USB. The installation seems to have gone well, as after the installation I can see the partitions I have created in Windows Device Manager. I currently run Lubuntu on my laptop, but it is not a dual boot. I'm assuming this is a bootloader issue and I am assuming that inside those partitioned files in my screenshot there is a working Ubuntu 12.04. I just have no way of getting to it. Update: (copied from comment) I booted using my Ubuntu live USB and used the Boot-Repair tool suggested in . Upon opening the tool I saw that it was recognizing my SSD as a removable drive and defaulting to install on the HDD. Once I realized that I was able to force install onto the SSD. My computer can now boot Ubuntu. |
I am currently working in ArcGIS 10.2.2 for Desktop and would like to know if there is a workflow for creating a unique ID for polygons within a shapefile based on their location. I am using data driven pages that are clipped to individual Township/Range/Sections of a city. There is polygon information that spans the entire city, but would like to create some type of unique identifier that allows users (of the exported attribute table) to quickly see where a polygon is located based on the identifier. What I currently have in mind is to list the Township/Range/Section and add a numeric suffix. For example, in the image below the first polygon in Township26-Range42-Section27 (highlighted in red) would be 26-42-27-1. The Township/Range/Section information is saved in another shapefile, so I am not sure the best process to append that info to the individual polygons within this other shapefile based on location. | I have used the Grid index feature tool to create an index grid. The label/attribution of the page names are populated in a "row" orientated manner. eg lef to right a1,a2,a3,a4,a5,a6 b1,b2,b3,b4,b5,b6 c1,c2,c3,c4,c5,c6 How can I calculate a field so I can have the page names label/attribution in a "column" orientation?eg: a1,b1,c1,d1,e1 a2,b2,c2,d2,e2 a3,b3,c3,d3,e3 a4,b4,c4,d4,e4 |
I just had a chat with my real analysis teacher today, we talked about how there is no $\sigma$-algebra such that it has countably many elements, but finitely many. In the end, he said that I can visualize it by drawing out the $\sigma$-algebra on (0,1) using intervals. But I'm not too sure how to do that, should I draw it out on the real line? Or can I use any type of diagram? | I am going over a tutorial in my real analysis course. There is an proof in which I don't understand some parts of it. The proof relates to the following proposition: ($S$ - infinite $\sigma$-algebra on $X$) $\implies $ $S$ is uncountable. Proof: Assume: $S=\{A_{i}\}_{i=1}^{+\infty}$. $\forall x\in X: B_{x}:=\cap_{x\in A_{i}}A_{i}$. [Note: $B_{x}\in S$ $\impliedby$ ($B_{x}$ - countable intersection]. Lemma: $B_{x}\cap B_{y}\neq\emptyset \implies B_{x}=B_{y}$. Proof(of lemma): $z\in B_{x}\cap B_{y} \implies B_{z}\subseteq B_{x}\cap B_{y}$. 1.$x\not\in B_{z} \implies x\in B_{x}\setminus B_{z} \wedge B_{x}\setminus B_{z} \subset S \wedge B_{x}\setminus B_{z} \subset B_{x}$ (contradiction:$\space$ definition of $B_{x}$) $\implies$ $B_{z}=B_{x}$ 2.$y\not\in B_{z} \implies y\in B_{y} \setminus B_{z} \space \wedge \space B_{y}\setminus B_{z} \subset S \space\wedge\space B_{y} \setminus B_{z}\subset B_{y} $(contradiction: definition of $B_{y}$) $\implies$ $B_{z}=B_{y}$ $\implies B_{x}=B_{y} \space \square$ Consider: $\{B_{x}\}_{x\in X}$. If: there are finite sets of the form $B_{x}$ then: $S$ is a union of a finite number of disjoint sets $\implies$ $S$ is finite $\implies$ there is an infinite number of sets of the form $B_{x}$. $\implies$ $|\bigcup\limits_{i\in A \subseteq\mathbb{N}}B_{x_{i}}| \geq \aleph_{0}$.(contradiction) $\square$ There are couple of things I don't understand in this proof: Why the fact that we found a set ($B_{x}\setminus B_{z}$) in $S$ containing $x$ and is strictly contained in $B_{x}$ a contradiction ? Why if there are only a finite number of different sets of the form $B_{x}$ then $S$ is a union of a finite number of disjoint sets and is finite ? |
Hi Can anyone help with this situation. I am on Drupal 7.12 and I am getting a white page (or if I have enabled errors to show, a SQL has gone away error when I try to add or edit a specific content type: PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT rid, permission FROM {role_permission} WHERE rid IN (:fetch_0); Array ( [:fetch_0] => 1 ) in user_role_permissions() (line 752 of /var/www/vhosts/pen.org/staging.pen.org/modules/user/user.module). This only happens sometimes and when it does lasts a couple of days. And it goes away suddenly. During the time it happens, other content types are editable. The site also functions fine. Has anyone experienced this before? Any insight is much appreciated. Thanks. | Recently I started getting an error every time I try and add a content no matter what type. This is the error that shows up in the browser: Additional uncaught exception thrown while handling exception. Original PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] => 0 ) in comment_count_unpublished() (line 313 of /Applications/MAMP/htdocs/modules/comment/comment.module). Additional PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: INSERT INTO {watchdog} (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array ( [:db_insert_placeholder_0] => 1 [:db_insert_placeholder_1] => php [:db_insert_placeholder_2] => %type: !message in %function (line %line of %file). [:db_insert_placeholder_3] => a:6:{s:5:"%type";s:12:"PDOException";s:8:"!message";s:154:"SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] =&gt; 0 ) ";s:9:"%function";s:27:"comment_count_unpublished()";s:5:"%file";s:56:"/Applications/MAMP/htdocs/modules/comment/comment.module";s:5:"%line";i:313;s:14:"severity_level";i:3;} [:db_insert_placeholder_4] => 3 [:db_insert_placeholder_5] => [:db_insert_placeholder_6] => ; [:db_insert_placeholder_7] => [:db_insert_placeholder_8] => 127.0.0.1 [:db_insert_placeholder_9] => 1338336955 ) in dblog_watchdog() (line 154 of /Applications/MAMP/htdocs/modules/dblog/dblog.module). I also get the following error in my php error file: PHP Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in /Applications/MAMP/htdocs/includes/database/database.inc:2136 Stack trace: 0 /Applications/MAMP/htdocs/includes/database/database.inc(2136): PDOStatement->execute(Array) 1 /Applications/MAMP/htdocs/includes/database/database.inc(664): DatabaseStatementBase->execute(Array, Array) 2 /Applications/MAMP/htdocs/includes/database/database.inc(2315): DatabaseConnection->query('SELECT expire, ...', Array, Array) 3 /Applications/MAMP/htdocs/includes/lock.inc(167): db_query('SELECT expire, ...', Array) 4 /Applications/MAMP/htdocs/includes/lock.inc(146): lock_may_be_available('theme_registry:...') 5 /Applications/MAMP/htdocs/includes/theme.inc(447): lock_acquire('theme_registry:...') 6 /Applications/MAMP/htdocs/includes/bootstrap.inc(427): ThemeRegistry->set(Array) 7 [internal function]: DrupalCacheArray->__destruct() 8 {main} thrown in /Applications/MAMP/htdocs/includes/database/database.inc on line 2136 I am having a little trouble deciphering these error messages. Could anyone help me understand what's going on here? |
I am reading David Williams' "Probability with Martingales" and in this book he supposes that you are given the following information about some 'outcome' $\omega \in \Omega$: $$X_n(\omega) \ \text{s.t.} \ n\in \mathbb{N}$$ for a series of random variables $X_n:\Omega \rightarrow \mathbb{R}$. He then says, based on this information, $\sigma(X_n : n \in \mathbb{N})$ consists of 'events' $F$ such that for each point $\omega$, you can tell whether the event $F$ has occurred or not (that $\omega \in F$). However, no matter how hard I try to wrap my head around this vague idea, I can't seem to understand it. I don't understand how the 'information' provided helps to understand whether some event has occurred or not and what this means in terms of a sigma algebra generated by random variables (which also confuses me). Is there any easier way to understand what a sigma algebra generated by these functions actually is? | I've been trying to understand $\sigma$-algebras and how it encodes information in context of filtration. While certain parts seem clear and logical, I can't say I get the whole picture. I'll try to explain the counter-intuition I get with the classical example of : the probability space $\Omega = \{ HH, HT, TH, TT \}$ and a r.v. $X(\omega)$ equal to the number of heads. At times $0$, $1$ and $2$ the available information is represented using $\sigma$-algebras $\mathcal{F}_0=\{\emptyset,\Omega\}$, $\mathcal{F}_1=\{\emptyset, \Omega, \{HH,HT\},\{TH,TT\}\}$ and $\mathcal{F}_2=\{\emptyset, \Omega,\{HH,HT\},\{TH,TT\},\{HH\},\{HT\},\{TH\},\{TT\}\}$. One can notice that $X(\omega)$ is not measurable with respect to $\mathcal{F}_0$ and $\mathcal{F}_1$, because $X^{-1}((\frac{3}{2}; +\infty))=\{HH\}$. To me it is quite surprising: intuitively $X$ makes perfect sense at all times. In particular it has an expected value at time $0$, which I interpret as that the probability and value of all outcomes $\{\omega\}$ can be computed. How do you think of a non-measurable function? Here's another way of expressing the same confusion. The most natural choice of $\sigma$-algebra in a finite discrete case is $\mathcal{F}=2^\Omega$, and it is implicitly used in all elementary probability problems. However, this choice of $\mathcal{F}$ does not reflect the fact that some information is known or unknown, conditional probability does. Does it mean that the statement "$\sigma$-algebra is known information" make sense only in conditioning? Why is it convenient then? |
I've been having some trouble with an SQL statement I'm trying to create and I figured that someone here would probably be able to help me out. I've got two tables: Matches and Users. The Matches table consists of User_id and Partner_id that represents a user and their respective match (partner). Each time a user clicks a button, a new match will be found and a row will be created in the Matches table. Now, when a user clicks the button to find a match, I need to - randomly - find a user in the Users table that is not the user himself (obviously) and does not already have a relation to the current user in the Matches table. - This is where I get stuck. How can I pick a user based on the criteria that they do not already have a relation to the currently logged in user, through the Matches table? All answers are much appreciated. Thank you. Edit: Having read both and (as well as others) only had me more confused afterwards. - I simply didn't quite understand the answers that were given well enough to convert them to what would have been useful in my case. | I've got the following two tables (in MySQL): Phone_book +----+------+--------------+ | id | name | phone_number | +----+------+--------------+ | 1 | John | 111111111111 | +----+------+--------------+ | 2 | Jane | 222222222222 | +----+------+--------------+ Call +----+------+--------------+ | id | date | phone_number | +----+------+--------------+ | 1 | 0945 | 111111111111 | +----+------+--------------+ | 2 | 0950 | 222222222222 | +----+------+--------------+ | 3 | 1045 | 333333333333 | +----+------+--------------+ How do I find out which calls were made by people whose phone_number is not in the Phone_book? The desired output would be: Call +----+------+--------------+ | id | date | phone_number | +----+------+--------------+ | 3 | 1045 | 333333333333 | +----+------+--------------+ |
My 16 GB USB flash drive (SanDisk Cruzer SDCZ36-016G BL1008OFZB) got corrupted and I was going to format it, when I saw the setting for size only had one element in its dropdown menu: 1.00 GB. Thinking this would not change the real capacity, I proceeded to format it to the NTFS file system. Turns out, it was serious of only having 1 GB of space. Is there anything I can now do to recover the ~15 GB of space this piece of junk cannot hold anymore? | My USB drive used to be originally 8GB when I bought it. I'm trying to reformatted in Windows 7 by right clicking on the drive and selecting Format.... But the capacity only shows 250MB. Is there something I can do to get the original size back? Maybe it got partitioned in a weird way? The flash drive is a SanDisk Cruzer Micro 8GB. I got it from Wal-Mart but this is the same drive. |
I need to prove $(-\vec{v})+\vec{v}=\vec{0}$ using only the axioms of vector space addition and multiplication, except the commutativity axiom. I have tried using this approach $\vec{0}=\vec{v}+(-\vec{v})$ but I get stuck and can't find a way to get the $(-\vec{v})$ first. | I'm trying to prove commutativity of addition for vector spaces, using the axioms for vector spaces. Apparently commutativity can be proven! Im having trouble getting a good feel for what is allowed and what is not. Here's my work so far: $u+v+u+v = 2(u+v) = 2u + 2v = u+u+v+v = u+(u+v)+v$ Here I just wanna claim that $u+(v+u)+v = u+(u+v)+v$ $\Rightarrow -u+u+(v+u)+v+(-v) = -u+u+(u+v)+v+(-v)$ : here im just adding -u to the right, and -v to the left. Question: is this "adding to both sides" really legit in this context? Why? Quick help proof: $-v+v = (-1)v+(1)v = (-1+1)v = 0v = 0 = v-v$ And another: $ 0+v = v+(-v) + v = (1)v + (-1)v + v = (1-1)v + v = v = v+0$ We have $0 + (u+v) + 0 = 0+(v+u)+0 \Rightarrow u+v = v+u$ This feels ugly and not at all elegant, especially the great leap "add -u to both sides" feels completely out of place. Do I need more lemmas? Is there a more elegant way? //not homework or anything, just for my own pleasure, feel free to provide theory, as it is more insightful than solutions. :) Thanks! EDIT: corrected notation a little. |
If I double click a .odt (OpenOffice Document) file that's on a 4TB MyBook USB drive plugged into my router it tries to open it in Archive Manager. I have to right click it, go to "open with..." and click OpenOffice.org Calc. Can I change the default "Open with..." to OpenOffice Calc like in Windows, or is there something else I have to do to get it to open correctly? | How do I set the default program that I use? I have tried to open System Info → Default Program → change my program, but it won't work, Any idea? Or should I use Terminal? I want to replace the default movie player with VLC media player, because the current movie player is useless to me. |
Been struggling with this for a while now, just kind of spinning my wheels at this point. Any help/advice/anything much appreciated. This is a problem from Wade's Intro to Analysis, chapter 3. Suppose $f : \textbf{N} \to \textbf{R}$. If $\lim\limits_{n \to \infty}f(n + 1) - f(n) = L$, prove that $\lim\limits_{n \to \infty}\frac{f(n)}{n}$ exists and equals $L$. | Here's the problem in full. I've stared at it for hours and can't get anywhere, so a hint would be nice. Suppose that $f:\mathbb N\rightarrow\mathbb R$. If $$\lim_{n\rightarrow\infty}f(n+1)-f(n) = L$$ prove that $\lim_{n\rightarrow\infty}f(n)/n$ exists and equals $L$. This problem is marked with the word "Cauchy", so I'm guessing Cauchy sequences or something related to them will be necessary, but I can't figure out what. Edit: It appears as if the Stolz-Cesaro Theorem makes this quite easy. Unfortunately though, we have not discussed this, so I won't be able to use this. |
okay so I have windows 8 and am running Lubuntu as a VM using vmplayer. I have my laptop hooked up to an external monitor so I have the VM full screen on my laptop and windows 8 on the monitor. What I want is, suppose I have a word document opened up in windows 8 but I'm typing in my VM right now and I want to quickly switch to the word document in windows 8, is there a keyboard shortcut / way to create a keyboard shortcut to switch between the VM and host operating system? Because moving the mouse and clicking between the VM and host operating system is getting a bit annoying. | When working in full screen mode, I'd like a way to quickly switch between host and VM using a toggle key. How can I do this? Thanks. |
Most of the software is not thoroughly tested with Java 7 and I would like to install Oracle's JDK 6.0 on Ubuntu 11.10. Could someone please provide me the instructions for the same? | I want to install Oracle's JRE and to update to the latest version with the Software Updater when they released. Is there a Ubuntu package that is provided by Canonical or Oracle? Before release Java 7, I followed to install Java 6. But it doesn't work for Java 7. There is no package sun-java7-xxx. How can you install Java 7? |
Consider the Earth, and a bowling ball held 186,000 miles (1 light second) above it. When the ball is released, it will start to fall vertically downwards towards the Earth. Now consider the case if the Earth is moving sideways at 1000 miles/second. The bowling ball is released just as the Earth passes directly underneath. Does the ball fall a) vertically again, or b) does it fall towards where the Earth was 1 second before? Gravity propagating at the speed of light, would suggest answer b) but as most of the matter in the universe is travelling at very high speed, and planetary orbits are circularish, I think the answer is a) | A thought experiment: Imagine the Sun is suddenly removed. We wouldn't notice a difference for 8 minutes, because that's how long light takes to get from the Sun's surface to Earth. However, what about the Sun's gravitational effect? If gravity propagates at the speed of light, for 8 minutes the Earth will continue to follow an orbit around nothing. If however, gravity is due to a distortion of spacetime, this distortion will cease to exist as soon as the mass is removed, thus the Earth will leave through the orbit tangent, so we could observe the Sun's disappearance more quickly. What is the state of the research around such a thought experiment? Can this be inferred from observation? |
Problem: Let $ABC$ be a triangle and let its incircle touch $BC$ at $D$. Let $T$ be the tangency point of the $A$-mixtilinear incircle with circumcircle of $ABC$. Prove that $∠BTA = ∠CTD$. I recognised that it suffices to show that $KT$ is isogonal to $DT$.Then the first thing that came to my mind is harmonic quadrilateral.I don't whether it is true or not.I am new to the topic of isogonals. Help me how to start?? Edit:I asked to prove that the above marked angles are equal.The question which marked as possible duplicate is not the same.Angles which were to be proven are different.I hope this convince you this as different question.I use mobile so geogebra in android is very difficult so I drew diagram manually. | Let $FGH$ be a triangle with circumcircle $A$ and incircle $B$, the latter with touchpoint $J$ in side $GH$. Let $C$ be a circle tangent to sides $FG$ and $FH$ and to $A$, and let $D$ be the point where $C$ and $A$ touch, as shown here. Prove that $\angle FGH = \angle GDJ$. |
Okay so this might be a basic question/stupid question, but I cannot find an answer for it. So let's say we have a continuous random variable that returns a value in 0, 1. I know that the probability to observe any single given point in this interval is zero (one point over infinite). How come I can observe this point that has no probability to be observed ? | Can an observed event in fact be of zero probability? Of course, I know that there exist non-empty events of zero probability. Mu question is the reverse: given that we have observed an event (and we have no other information about it, just the fact that it has been observed), is it possible that the event has in fact zero probability? Or does an observation necessarily mean that the probability is strictly positive? Example context for the question: Suppose $x_i$ (countably many) are i.i.d on $[0,1]$, but we do not know the distribution they come from. It may be uniform on $[0,1]$, may be discrete, may be any legitimate distribution (discrete or continuous). Just imagine we have some sort of a machine that shows us one by one a list of randomly drawn numbers between $0$ and $1$. We are comparing the observed numbers one by one to some special number chosen beforehand, for example $\frac12$. Now, given that at some iteration we have observed that special number at least once, does that mean that $\frac12$ has some positive probability under that (unknown) distribution? And if the probability can be zero, can we nevertheless say that we will necessarily observe $\frac12$ again later, if we continue the experiment ad infimum? Also, disregard the "real world limitations" such as an inability to produce truly uniformly distibuted numbers, or rounding errors or any such thing. |
I am trying get an unused server up and running, it booted fine but i was greeted with the login window and none of the known passwords seem to work. The server I am trying to get to work is not a Domain Controller and has not been used in a long time. OS: Windows 2003 Server R2 Enterprise Edition I tried Ophcrack XP (there is no WinServer version of Ophcrack) - it couldn't locate the partitions with hashes. I tried mounting the partitions myself (#mount /dev/hda*x* /mnt/ntfs), but it gave me an error saying /dev/hda*x* didn't exist. Next I tried booting into a Ubuntu 10.04.3 LiveCD so that I could install and use chntpw - no go, Ubuntu Live wouldn't boot. Based on what I've read up the following tools may be of help: Windows Password recovery Petter Nordahl-Hagen's Offline NT Password & Registry Editor Openwall's John the Ripper EBCD – Emergency Boot CD - Bootable CD (R)ecovery (I)s (P)ossible Linux rescue system I am hoping that someone here has prior experience with Win2k3 Administrator password resets so that I don't end up having to try all of the above to find out which one works. | I got a brand new Windows 7 machine, installed the operating system, created one account and forgot its password. What can I do? There is no external CD, the operating system is loaded from somewhere inside the machine. I already tried to remember passwords and tried all candidates with all possible combinations of caps lock, num lock etc. |
I have these functions: $('.list-group .list-group-item.list-group-item-action').click(function(e) { $('.list-group .list-group-item.list-group-item-action.active').removeClass('active'); var $this = $(this); if (!$this.hasClass('active')) { $this.addClass('active'); } e.preventDefault(); }); document.querySelectorAll('.list-group-item').forEach(function(channel){ channel.onclick = () =>{ load_channel(channel); return false; } }); socket.on('create channel', data =>{ const button = document.createElement('button'); button.className = "list-group-item list-group-item-action"; button.innerHTML = `${data.channel}`; document.querySelector('.list-group').append(button); }); The last function dynamically creates a button in this list (ignore the jinja): <div class="list-group"> <button class="list-group-item list-group-item-action active">General</button> {% for channel in channels %} <button class="list-group-item list-group-item-action">{{ channel }}</button> {% endfor %} </div> But when it's created, the first two functions do not work. What is the solution? | I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off. This happens on page ready and works just fine. The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound. I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option. |
I have been looking for ways to full screen my Git terminal screen on windows. I tried tweaking the property settings but no luck. I found few crazy hacks online , but could not get it to work! :( I am at a loss to understand why I can't find an easy way to accomplish such basic thing. | Anyone know why doesn't the Windows command prompt window maximize to the full screen size? To the best of my knowledge, even in the new Windows 7 the command prompt window(cmd.exe) doesn't maximize to the full screen size like all other windows. This behavior is quite annoying for me, and I'm sure to many others as well. Note: The size of the command prompt window can be , but the size remains fixed regardless of the screen size. |
Given two disjoint closed sets, $F_1$ and $F_2$ in $\mathbb{R}$, prove that there exist disjoint open sets $G_1$ and $G_2$ such that $F_1 \subset G_1$ and $F_2 \subset G_2$ The answer is not trivial in that the distance between $F_1$ and $F_2$ could be going towards zero. | Theorem: Let $S_0, S_1 \subseteq \mathbb{R}^n$ be disjoint and closed. Then there exist disjoint open sets $T_0, T_1 \subseteq \mathbb{R}^n$ such that $S_0 \subset T_0, S_1 \subset T_1$. How to prove this theorem without Urysohn functions? I know that $S_0^c$ contains $S_1$ and vise versa, but I don't know how to proceed from here. |
I just removed some effects using ccsm, switched to the AMD proprietary driver, rebooted and after I log in, the unity panel is no longer there. If I hit the windows key or the alt key, nothing happens. I can hit ctrl+alt+t to get a terminal (and thus launch apps via commandline). Does anyone know how I can fix this? What logs do I need to post here for help? Edit #1: As suggested by @cprofitt I just ran: dconf reset -f /org/compiz/ && setsid unity I'm seeing some compiz messages in the terminal now: unity-panel-service: no process found compiz (core) - Info: Loading plugin: core compiz (core) - Info: Starting plugin: core compiz (core) - Info: Loading plugin: ccp compiz (core) - Info: Starting plugin: ccp compizconfig - Info: Backend : gsettings compizconfig - Info: Integration : true compizconfig - Info: Profile : unity compiz (core) - Info: Loading plugin: composite compiz (core) - Info: Starting plugin: composite compiz (core) - Info: Loading plugin: opengl X Error of failed request: BadRequest (invalid request code or no such operation) Major opcode of failed request: 155 (ATIFGLEXTENSION) Minor opcode of failed request: 66 () Serial number of failed request: 23 Current serial number in output stream: 23 compiz (core) - Info: Unity is not supported by your hardware. Enabling software rendering instead (slow). X Error of failed request: BadRequest (invalid request code or no such operation) Major opcode of failed request: 155 (ATIFGLEXTENSION) Minor opcode of failed request: 66 () Serial number of failed request: 23 Current serial number in output stream: 23 compiz (core) - Info: Unity is not supported by your hardware. Enabling software rendering instead (slow). compiz (core) - Info: Starting plugin: opengl Compiz (opengl) - Fatal: glXQueryExtensionsString is NULL for screen 0 compiz (core) - Error: Plugin initScreen failed: opengl compiz (core) - Error: Failed to start plugin: opengl compiz (core) - Info: Unloading plugin: opengl compiz (core) - Info: Loading plugin: compiztoolbox compiz (core) - Info: Starting plugin: compiztoolbox compiz (core) - Error: Plugin 'opengl' not loaded. | When I login, nothing happens. I am presented with my desktop wallpaper. No Dash, no Launcher, nothing. |
I am trying to generate reports in different languages like French, Spanish, etc. The report is being viewed using MS Excel 2007, It displays OK in English but not in French nor in Spanish when executed in Linux environment. All languages works in Windows Server but when running it in Linux, I am experiencing the problem I described above. The code is in Java and, I started like this: String contentType = "text/csv; charset=utf-8"; // resp is HttpServletResponse resp.setCharacterEncoding("utf-8"); resp.setHeader("Cache-Control", "max-age=0,must-revalidate"); resp.setHeader("Pragma", "cache"); resp.setDateHeader("Last-Modified", System.currentTimeMillis()); resp.setHeader("Content-disposition", "attachment; filename=\"Report.csv\""); resp.setContentType(contentType); OutputStream os = resp.getOutputStream(); os.write(new byte[] { (byte)0xEF, (byte)0xBB, (byte)0xBF }); //os.print("\uFEFF".getBytes()); <<- tried this too, did not worked! //where sb is StringBuffer sb = new StringBuffer(); //and string values were added by sb.append("\"" + someString + "\","); os.write(sb.toString().getBytes()); Please help and thank you in advance. | I am programmatically exporting data (using PHP 5.2) into a .csv test file. Example data: Numéro 1 (note the accented e). The data is utf-8 (no prepended BOM). When I open this file in MS Excel is displays as Numéro 1. I am able to open this in a text editor (UltraEdit) which displays it correctly. UE reports the character is decimal 233. How can I export text data in a .csv file so that MS Excel will correctly render it, preferably without forcing the use of the import wizard, or non-default wizard settings? |
Show $f(x):=\sqrt{x}$ is uniformly continuous on $[0,1]$. What I did: Need to show that $\forall \varepsilon>0: \exists\delta>0$ such that $\forall x,y\in(0,1): |x-y|<\delta\Rightarrow|f(x)-f(y)|<\varepsilon$ Choose $\delta=\varepsilon^2$. then for $x,y\in(0,1)$ with $|x - y| < \delta$, $|f(x)-f(y)|=|\sqrt{x}-\sqrt{y}|$ $|\sqrt{x}-\sqrt{y}|\le|\sqrt{x}+\sqrt{y}|$ $|\sqrt{x}-\sqrt{y}|^2\le|\sqrt{x}-\sqrt{y}||\sqrt{x}+\sqrt{y}| =|x-y|< \varepsilon^2$ $|\sqrt{x}-\sqrt{y}|\le\sqrt{|x-y|}<\sqrt{\varepsilon^2}=\varepsilon$ | Prove that the function $\sqrt x$ is uniformly continuous on $\{x\in \mathbb{R} | x \ge 0\}$. To show uniformly continuity I must show for a given $\epsilon > 0$ there exists a $\delta>0$ such that for all $x_1, x_2 \in \mathbb{R}$ we have $|x_1 - x_2| < \delta$ implies that $|f(x_1) - f(x_2)|< \epsilon.$ What I did was $\left|\sqrt x - \sqrt x_0\right| = \left|\frac{(\sqrt x - \sqrt x_0)(\sqrt x + \sqrt x_0)}{(\sqrt x + \sqrt x_0)}\right| = \left|\frac{x - x_0}{\sqrt x + \sqrt x_0}\right| < \frac{\delta}{\sqrt x + \sqrt x_0}$ but I found some proof online that made $\delta = \epsilon^2$ where I don't understand how they got? So, in order for $\delta =\epsilon^2$ then $\sqrt x + \sqrt x_0$ must $\le$ $\epsilon$ then $\frac{\delta}{\sqrt x + \sqrt x_0} \le \frac{\delta}{\epsilon} = \epsilon$. But then why would $\epsilon \le \sqrt x + \sqrt x_0? $ Ah, I think I understand it now just by typing this out and from an earlier hint by Michael Hardy . |
Compute the Fourier transform of the following tempered distributions on $\mathbb R^n$, which, for $\phi \in \mathcal S(\mathbb R^n)$ are given by $T_1(\phi) := \int_{\mathbb R^n} x^{\alpha} \phi(x) dx$, $\alpha \in \mathbb N_0^n$. $T_2(\phi) := \int_{\mathbb R^n}\sin(\langle a, x \rangle_{\mathbb R^n}) \phi(x)dx$, $a \in \mathbb R^n$. $T_3(\phi) := \int_{\mathbb R} \mathbb 1_{[-1,1]}(x) \phi(x) dx$. Here's what I know and what I've tried so far $\mathcal F$ denotes the Fourier transform $$ \mathcal{F} f (\xi) := \hat{f}(\xi) := (2 \pi)^{-n/2} \int_{\mathbb R^n} f(x) e^{-i \langle x, \xi \rangle} dx $$ and $\mathcal{S}$ the Schwartz space. We defined $(\mathcal{F} T)(\phi) = T(\mathcal{F}(\phi))$. I am also going to use the following rules for the Fourier transform: $D^{\alpha}(\mathcal{F} \phi)(\xi) = (-i)^{|\alpha|} \mathcal{F}(x^{\alpha} \phi)(\xi)$ and $\xi^{\alpha} (\mathcal{F}\phi)(\xi) = (-i)^{| \alpha |} \mathcal{F}(D^{\alpha} \phi)(\xi)$. Is the following calculation correct? \begin{align*} \mathcal{F}(T_1(\phi)) & = T_1(\mathcal{F}(\phi)) = \int_{\mathbb{R}^n} x^{\alpha} \hat{\phi}(x) dx = (-1)^{| \alpha |} \int_{\mathbb{R}^n} (\hat{\phi}(x))^{(\alpha)} dx \\ & = (-1)^{|\alpha|} \int_{\mathbb{R}^n} (-i)^{|\alpha|} \mathcal{F}(t^{\alpha} \phi)(x) dx = i^{|\alpha|} \int_{\mathbb{R}^n} \mathcal{F}(t^{\alpha} \phi)(x) dx \\ & = i^{|\alpha|} \mathcal{F}^{-1}(\mathcal{F}(t^{\alpha} \phi))(0) = i^{| \alpha |} 0^{\alpha} \cdot \phi(0) = \begin{cases} i^{| \alpha |} \phi(0), & \alpha = 0, \\ 0, & \text{else.} \end{cases} \end{align*} I am pretty stuck with this one as I haven't found a way to further reduce this expression. Any hints? \begin{align*} \mathcal{F}(T_2(\phi)) = T_2(\hat{\phi}) = \int_{\mathbb R^n} \sin(\langle a, x \rangle) \hat{\phi}(x) dx \end{align*} The next step I will try is to shift the Fourier transform to the sin, as I have done in 3. But I am even struggling to evaluate the integral for $n = 1$, which is $$ \int_{\mathbb R} \sin(a x) e^{-i x \xi} dx = \frac{e^{-i \xi x}(a \cos(ax) + i \xi \sin(ax))}{\sqrt{2 \pi} (a - \xi)(a + \xi)}\bigg|_{x = - \infty}^{\infty} $$ Here I redristribute the Fourier transform inside the integral, which should be valid by Fubini. Is it valid in this case? \begin{align*} \mathcal{F}(T_3(\phi)) & = T_3(\hat{\phi}) = \int_{\mathbb{R}} \mathbb 1_{[-1,1]}(x) \hat{\phi}(x) dxf = \int_{\mathbb{R}} \widehat{\mathbb 1_{[-1,1]}}(x) \phi(x) dx \\ & = \int_{\mathbb{R}} \sqrt{\frac{2}{\pi}} \frac{\sin(x)}{x} \phi(x) dx \end{align*} Edit With @guy3141's hint I proceeded as follows: With $\Im(x) = \frac{x - \bar{x}}{2i}$ we have \begin{align} \int_{\mathbb R^n} \sin(\langle a, x \rangle) e^{-i \langle x, \xi \rangle} dx & = \frac{1}{2i} \int_{\mathbb R^n} \left(e^{i \langle a, x \rangle} - e^{-i \langle a, x \rangle}\right)e^{-i \langle x, \xi \rangle} dx \\ & = \frac{1}{2i} \int_{\mathbb R^n} e^{-i \langle \xi - a, x \rangle} - e^{-i \langle \xi + a, x \rangle} dx. \end{align} Now we can use Fubini's theorem (F) to evaluate both summands separately: \begin{align} \int_{\mathbb R^n} e^{- i \langle \xi \pm a, x \rangle} dx & = \int_{\mathbb R^n} \prod_{k = 1}^{n} e^{-i x_k (\xi_k \pm a_k)} dx \overset{\text{(F)}}{=} \prod_{k = 1}^{n} \int_{\mathbb R} e^{-i x_k (\xi_k \pm a_k)} dx_k, \end{align} but I fear that I can't use Fubini's theorem as the integral on the RHS doesn't converge. | Let $T$ be a tempered distributions, and let $S(x) = e^{i\alpha x}T(x)$, where $\alpha \in \mathbb{R}$. Find a formula that relates the Fourier transforms $\hat S$ and $\hat T$. Find the Fourier transform $\hat f_\alpha$ of $f_\alpha (x) = \sin \alpha x$. Find $\lim_{\alpha \to \infty} \alpha \hat f_\alpha$ in the sense of (tempered) distributions. |
$\sum_{n=1}^{+\infty}\left[n \log\left ( \frac{2n+1}{2n-1} \right )-1\right]$ ,converges or not My attempt $a_n=n \log\left ( \frac{2n+1}{2n-1} \right )-1 \\ \\ \log \left ( \frac{2n+1}{2n-1} \right )=\log \left ( 1+\frac{2}{2n-1} \right ) \sim \frac{2}{2n-1} \ (n\rightarrow +\infty) \\ \\ a_n=n\log \left ( 1+\frac{2}{2n-1} \right )-1 \sim n \frac{2}{2n-1}-1=\frac{2n}{2n-1}-1=\frac{1}{2n-1} \\ \\ $ $\sum_{n=1}^{+\infty}\frac{1}{2n-1} $ diverges ,then $\sum_{n=1}^{+\infty}a_n $ diverges but according to Wolfram $\sum_{n=1}^{+\infty}a_n=\frac{1}{2}-\frac{\log 2}{2}$ where is the mistake in my solution please? thanks | I am investigating the convergence of $$\sum _{n=1}^{\infty }\left\{ 1-n\log \frac {2n+1} {2n-1}\right\} $$ Now as per Cauchy's test for absolute convergence. If $\overline {\lim _\limits{n\rightarrow \infty }}\left| u_{n}\right|^{{1}/{n}} < 1,\sum _\limits{n=1}^{\infty }u_{n}$ converges absolutely Obviously, if $\overline {\lim \limits_{n\rightarrow \infty }}\left| u_{n}\right|^{{1}/{n}} > 1,\sum _\limits{n=1}^{\infty }u_{n}$ does not converge. I observed $$\overline {\lim _{n\rightarrow \infty }}\left| \log \left( \dfrac {2n+1} {2n-1}\right) ^{-n}\right| = \overline {\lim _{n\rightarrow \infty }}\left| \log \left( 1-\dfrac {1} {n-{1}/{2}}\right) ^{-n}\right|$$ Could I take the negative power of $n$ outside the absolute brackets here? I guess even if I could establish $\log$ part converges that would only show that the overall series diverges right. Is that the correct result ? Any alternative lines of attacking this problem would be much appreciated. |
So I typed in lscpu into my terminal and saw this: CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per core: 2 Core(s) per socket: 2 Socket(s): 1 The no. of CPU(s) is 4 here because of the formula: No. of CPUs = Sockets X Cores per socket X Threads per Core But the question is, what exactly is a CPU? Why are we including threads in the above formula? | You can see the output from lscpu command - jack@042:~$ lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 56 On-line CPU(s) list: 0-55 Thread(s) per core: 2 Core(s) per socket: 14 Socket(s): 2 NUMA node(s): 2 Vendor ID: GenuineIntel CPU family: 6 Model: 79 Model name: Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz Stepping: 1 CPU MHz: 2600.000 CPU max MHz: 2600.0000 CPU min MHz: 1200.0000 BogoMIPS: 5201.37 Virtualization: VT-x Hypervisor vendor: vertical Virtualization type: full L1d cache: 32K L1i cache: 32K L2 cache: 256K L3 cache: 35840K NUMA node0 CPU(s): 0-13,28-41 NUMA node1 CPU(s): 14-27,42-55 I can see that there are 2 sockets (which is like a processor ??) and inside each of the socket we have 14 cores. So, in total 2x14=28 physical cores. Normally, a CPU can contain multiple cores, so number of CPUs can never be smaller than number of Cores. But, as shown in the output CPUs(s): 56 and this is what is confusing me. I can see that Thread(s) per core: 2, so these 28 cores can behave like 2x28=56 logical cores. Question 1: What does this CPUs(s): 56 denote? Does CPU(s) denote number of Virtual/Logical core, as it cannot be a Physical core core atleast? Question 2: What does this NUMA node mean? Does it represent the socket? |
I am registered on about 80 SE sites, am an "avid user"(>200 rep) on about 30, and a modest user (103-199 rep) on about 20 more. Once when I tried to ask a question on Open Data (my "new user" site), the "systemwide" 40 minute rate limit kicked in. So I asked on meta , given that my previous post on the site was days ago. So a mod commented by telling me about the systemwide post rule and asking me if I had just come from another site. I said, yes, History (my best site, 40K rep.) I can see why I would be rate limited on Open Data. I can understand that I would be rate limited if I had come from say, Open Source, another site where I'm a new user. But did the system "rate limit" me as a new user on one site, based on my activity on History, an "established" site? Also, about the one day new user rate limit after a question is downvoted: Suppose a question on the previous site receives two upvotes and one downvote (net of one upvote). Is that a different situation than receiving one down downvote and no upvotes? Or does the downvote count in both cases, including the one where there were offsetting upvotes? How about if the downvoted question on the previous site was deleted? I don't have this problem when going from one "established" (greater than 125 rep) site to another. I understand why a person would be "rate limited" going from one new site to another; SE wants people to ask questions 40 minutes apart on their new sites. In my case, I was blocked when I left an "established" site (my best) to go to a new site, which is almost the same as going to a new site de novo. Why would this be? Or can't the system tell that my "first" site was an established site? Would I have been similarly rate limited if I went first to the "new" site, and 39 minutes later to the established site? Or does the rate limit apply only when the "destination" site is the new site? Put another way, there are four permutations of established and new sites: 1) established to established 2) new to new 3) established to new and 4) new to established. The block doesn't apply in the first case, does apply in the second case, and apparently applies in the third. What about the fourth? And why? Because it is not "uniform" across sites in the four cases. Edit: Unlike the other question, this one is not about the general rule. It is about the "special case" described in the paragraph above. | A bit of background: I have Asperger's syndrome. One consequence of that is, generally, even a simple half-a-page post takes from 30 to 60 minutes to write and leaves me quite tired. (Which, as far as I'm aware, is much slower than average.) On the other hand, sometimes I get in the mood, feel all giddy inside and enter a sort of word-mincing berserker rage, in which case the words seem to flow a bit better and faster and less tiringly. Also, due to various life-related reasons, at the moment I have about 4 hours of free time I can spend with computer. So, for this reason, I have created a list of topics I would like to ask (and been wanting for quite some time) on various sites of Stack Exchange, and been carrying it around for two weeks until I finally got into a mood where I can write at a reasonable pace and had enough time. Perceived cause: 40-minute limit per question seems to be applied across all sites of Stack Exchange, even on unrelated sub-sites (possibly applicable only to the stackexchange.com domain). The problem: I posted . Then I tried to post another question on Sci-Fi, but ran into the 40-minutes blockade. That's perfectly reasonable and understandable - a common mechanism to stop the site from being flooded with spam. So, I switched to Gaming SE, wrote a question from the list... and was greeted by the same message. Even though the last question I posted there was 20th February. I checked back to the question on Sci-Fi SE and, sure enough, its timestamp said it was posted 33 minutes ago. The actual question: Is that a bug, or is that a feature? If the latter, what's the justification for it? If that's intended, does this mean that instead of writing questions and posting them once I finished, do I have to save them to a text file, and then post them throughout the day with an egg-timer in hand? EDIT: Posting here, on Meta SE, did not re-trigger the limit, and I managed to , but when I tried to post a question to Sci-Fi SE, I got the "You can only post once every 40 minutes." again - 1 hour after the original question on Sci-Fi SE. |
I've got a question on getting 1 Gbit/s on my D-Link DGS-1005A. I managed to test getting 1 Gbit/s (>700 Mbit/s) connections on my PC, but now it's stuck at 100 Mbit/s. Fiddling with my Ethernet controller doesn't give me a 1000 Mbit/s full duplex mode, previously set to auto-negotiation. So where do I go for this? I've already checked for the list, but I don't see something for home users ( is business teams). | I see a lot of desktop admin questions being migrated to Super User. Are we positing that enterprise desktop support belongs on Super User? To me it's just as valuable for Server Fault to have information on things like troubleshooting a on Windows XP on Server Fault because the troubleshooting steps for a desktop BSoD and a server BSoD are the same. To me, Super User was put out as the consumer/non-business version of Server Fault. |
A few days ago I was using the Google iOS app (not Chrome, but the specific "Google" app that you can download in the App Store) to go to shady website in an attempt to stream a movie online. Stupid, I know. I didn't download anything, and I didn't think I clicked on anything, but I started getting a prompt to call a number. As far as I could tell, it wasn't any of the obviously fake ones that tell you to call a number because your phone is compromised or anything. It looked like the legit prompt that pops up when you click on a number in iOS where it has "Call 808-xxx-xxxx" on the top row and "Cancel" on the bottom row at the bottom of your screen. This is the prompt that comes up if you click on a number in any app. Anyways, it popped up a thousand times and stopped when I killed the app. How does that exploit work? Did the webpage just trick my phone into thinking I clicked on a number a few dozen times? Is there any chance I got a virus from the website? Things have seemed fine since. Is there any way to tell if you have a virus aside from just the normal weird symptoms? | A few days ago I was using the Google iOS app (not Chrome, but the specific "Google" app that you can download in the App Store) to go to shady website in an attempt to stream a movie online. Stupid, I know. I didn't download anything, and I didn't think I clicked on anything, but I started getting a prompt to call a number. As far as I could tell, it wasn't any of the obviously fake ones that tell you to call a number because your phone is compromised or anything. It looked like the legit prompt that pops up when you click on a number in iOS where it has "Call 808-xxx-xxxx" on the top row and "Cancel" on the bottom row at the bottom of your screen. This is the prompt that comes up if you click on a number in any app. Anyways, it popped up a thousand times and stopped when I killed the app. How does that exploit work? Did the webpage just trick my phone into thinking I clicked on a number a few dozen times? Is there any chance I got a virus from the website? Things have seemed fine since. Is there any way to tell if you have a virus aside from just the normal weird symptoms? |
We all know that heat or high voltage makes atoms into an excited state, stripping off the electrons off of their nucleus. But how much heat do you exactly need to create plasma, or have the majority of the atoms to be ionized? | I'm looking for a list of nearly all elements and the temperatures they can reach when in a state of plasma. It is for a project I am working on. However, there isn't a list on google. Preferably one that is hot enough to survive a drop from orbit. |
Is there a term for such a person? Background: Someone who is a pathological liar, an overt exaggerator. He would want to take center-stage, makes up stories to capture interest, and applies his stated qualities in positive as well as negative interactions. Such a person, I believe borderlines personality disorder. But can we summarize him in a word? Some words that appear to have different connotations: Exaggerator braggart | What is a single word for a person who, as a habit, exaggerates a lot when relating information? So for example, they relate something that happened but exaggerate so much that they are including clear falsehood and they are well known for doing that. |
I am trying to scan a string and put it in an if like so: (this is just an example part of the whole program) Scanner scan=new Scanner(); System.out.print("Enter the word..."); String a=scan.nextLine(); if (a=="Hi") System.out.println("Hello!") Else System.exit(0); So im checking if the user said "Hi" , but it doesnt work like this, I want a way to do it. I have just started learning java so my questions might seem a little amateur but your answers will help a lot. | 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? |
In the case I have two numbers large enough to justify using scientific notation twice $A \times 10^{B \times 10^C}$ or $Ae+Be+C$ How would I calculate Modulo without taking the numbers or any part of them out of scientific notation? | I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two: $13^{100} \bmod 7$ $7^{100} \bmod 13$ I've also heard of this formula: $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$ But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?) Any hints or pointers in the right direction would be great. |
Let's say I have a set of sources that supply an array of tagged items where the type of the item varies from source to source. I want to create a default implementation of the source method, but I haven't been able to find a way to do so without getting a compiler warning about unchecked conversions. To begin with, here's my generic tagged item: public class TaggedItem<T> { private final String tag; private final T item; public TaggedItem(String tag, T item) { this.tag = tag; this.item = item; } public String getTag() { return tag; } public T getItem() { return item; } } and a sample concrete implementation where the item type is String: public class TaggedString extends TaggedItem<String> { public TaggedString(String tag, String item) { super(tag, item); } } Now here's my generic source interface: public interface ITaggedItemSource<T> { default TaggedItem<T>[] getTaggedItems() { return new TaggedItem[0]; // (1) } default TaggedItem<T>[] getTaggedItems(Class<TaggedItem<T>> clazz) { return (TaggedItem<T>[])Array.newInstance(clazz, 0); // (2) } default List<TaggedItem<T>> getTaggedItemList() { return new ArrayList<TaggedItem<T>>(); } } I began with the first method. However this causes the following compiler warning at (1): Type safety: The expression of type TaggedItem[] needs unchecked conversion to conform to TaggedItem<T>[] So I added the second method. However this causes the following compiler warning at (2) Type safety: Unchecked cast from Object to TaggedItem<T>[] Finally, for the third method, I converted my array to a List and I was warning free. For the record, here's an example of a concrete source. public class TaggedStringSource implements ITaggedItemSource<String> { @Override public TaggedItem<String>[] getTaggedItems() { TaggedString[] items = new TaggedString[1]; items[0] = new TaggedString("t1", "data"); return items; } @Override public TaggedItem<String>[] getTaggedItems(Class<TaggedItem<String>> clazz) { TaggedString[] items = new TaggedString[1]; items[0] = new TaggedString("t1", "data"); return items; } @Override public List<TaggedItem<String>> getItemList() { List<TaggedItem<String>> items = new ArrayList<>(); items.add(new TaggedString("t1", "data")); return items; } I should note that both the default array and List implementations work just fine despite the compiler warnings. (As you'd expect I suppose, after all, they're just warnings.) My questions are: Is it possible to have a method that uses arrays that does not cause a warning? If so, how? Why is it possible to avoid a warning when using Lists? | Due to the implementation of Java generics, you can't have code like this: public class GenSet<E> { private E a[]; public GenSet() { a = new E[INITIAL_ARRAY_LENGTH]; // error: generic array creation } } How can I implement this while maintaining type safety? I saw a solution on the Java forums that goes like this: import java.lang.reflect.Array; class Stack<T> { public Stack(Class<T> clazz, int capacity) { array = (T[])Array.newInstance(clazz, capacity); } private final T[] array; } But I really don't get what's going on. |
There is 1 message, it is encrypted with 6 different keys, each has E = 5. I tried various attacks, but they do not seem to work. Is it possible to receive a private key / encrypted message? Is it safe to use a small E? | I have three different 1024-bit public keys with common exponent $e$ but different moduli. A message $m$ is encrypted (without padding) using the three keys, which results in three different encrypted messages. Given the three pairs of public keys $(N_i,e)$ and the encrypted messages $c_i=m^e\bmod N_i$ , how do I decipher the original message $m$ ? |
okay so basically I've played with friends while im at their house. Well if we live in the same city but far away is it possible to just do as you normally do and open lan then type in the IP, etc. Hahah I'm rlly stupid | I would like to create a minecraft server for me and and my boyfriend to play on. How do I set it up? Do I need any additional software? Do you have some links to walkthroughs or tutorials? I have tried to set this up a few times but have failed every time. |
Example of such words are: As far as I know, at least in American English, words that have single syllable double their ending consonant letters when modified. Such as: hop - hopping cut - cutting map - mapped Another part of my question is, are there any exemptions to this rule? Does this rule also apply in British English? If yes, what are the exemptions? If not, what rules apply in regard to this specific matter? If there are no such rules, perhaps the only way to go is by memorization. Could anyone cite me a real good exhaustive list of such words? | Initially, my question was: is "focussed" or "focused" the correct past tense of "focus", but since this applies to a lot of words, I would like to generalize and ask: is there supposed to be a rule when to double the consonant? |
I've got a small custom made blog type thing and want to display the date posted next to comments. I'd like to do it in the format of: posted 23 secs ago posted 43mins ago posted 1hr ago posted 1day ago posted 2 weeks ago ... probably won't get much longer than that because articles older than a month aren't shown. I can stored the actual date in datetime or timestamp format in MySQL... Anyone know of a function that's existing for PHP which I could use to do this? I haven't really found anything that suits yet. | Given a specific DateTime value, how do I display relative time, like: 2 hours ago 3 days ago a month ago |
What does it mean a value is statistically significant and when does it occur? For example, at a 5% level of significance, do p-values above or below 0.05 indicate significance? | I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error. I understand that p-values are defined as "the probability of obtaining a test statistic at least as extreme as the one we actually observed", while a significance level is just an arbitrary cutoff value to gauge if the p-value is significant or not. Type I error is the error of rejected a null hypothesis that was true. However, I am unsure regarding the difference between significance level and the type I error, are they not the same concept? For example, assume a very simple experiment where I flip a coin 1000 times and count the number of times it lands on 'heads'. My null hypothesis, H0, is that heads = 500 (unbiased coin). I then set my significance level at alpha = 0.05. I flip the coin 1000 times and then I calculate the p-value, if the p-value is > 0.05 then I fail to reject the null hypothesis and if the p-value is < 0.05 then I reject the null hypothesis. Now if I did this experiment repeatedly, each time calculating the p-value and either rejecting or failing to reject the null hypothesis and keeping a count of how many I rejected/failed to reject, then I would end up rejecting 5% of null hypotheses which were in actuality true, is that correct? This is the definition of type I error. Therefore, the significance level in Fisher significance testing is essentially the type I error from Neyman-Pearson hypothesis testing if you performed repeated experiments. Now as for p-values, if I had gotten a p-value of 0.06 from my last experiment and I did multiple experiments and counted all the ones that I got a p-value from 0 to 0.06, then would I also not have a 6% chance of rejecting a true null hypothesis? |
can I write: select * from table where id = 1 or should I write: SELECT * FROM table WHERE id = 1 or no difference? | Is SQL case sensitive. I've used MySQL and SQL Server which both seem to be case in-sensitive. Is this always the case? Does the standard define case-sensitivity? |
There are multiple sources from which you can gain natural attacks (Bloodlines, Rage Powers, Racial Features etc.) What happens when you gain, say, a Bite Attack from being a with the "Toothy" Racial trait and a Barbarian with the Rage Power? Does it stack somehow? | My character has a bite attack from his race. What happens if he gains another bite attack from class abilities or spells? Does the damage increase? Can he make more than one attack? Or is it simply that only the better version applies? I would prefer answers from a Pathfinder context but 3.5e is also acceptable. |
One can use the mobile data from a PC using the USB tethering feature. Is there any way to do the opposite, that is use the PC data from mobile, using USB cord or any other cord or app? My phone is Samsung Galaxy On7 with Android 6.0 Marshmallow. Phone is not rooted. | My HTC G2 phone is rooted and running Cyanogenmod 7 I don't have a data plan. Sometimes I want to connect the phone to the Internet when there isn't Wi-Fi, to update Market apps, backup SMS messages to Gmail, sync new contacts from Gmail, etc. Things I can't do with USB mass storage mode. I have a Windows 7 Professional computer connected to the Internet, but I'm not allowed to set up an ad-hoc Wi-Fi network. (If I do, they will notice and hunt me down.) Is there a way for the phone to access the Internet through the USB connection to the computer? If so, how do I set it up? |
I have problem with dynamic generated buton from typeahead twitter: templates: { empty: [ "<button type='button' class='btn btn-danger btn-sm form-add' data-toggle='modal' data-target='#form-add' data-title='Add' data-text='abc' data-form-action='' data-parent-id=" + $(self).data("parent-id") + ">Add</button>" ].join("\n"), suggestion: function(data) { return "<p>" + data.name + "</p>"; }} and I would like send data-parent-id to my modal on click event on button Add and this not work. $("button.form-add").on("click", function(e) { console.log("typeahead"); }); What is wrong ? Regards | I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off. This happens on page ready and works just fine. The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound. I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option. |
Why is $\log_e(x)'=\ln(x)'= 1/x$? how to prove the differentiation rule. ofc that means also $\int(1/x)dx=\ln(x) + c$ I think that the derivative of the $\ln$ of a variable with respect to the variable being 1/x is an axiom to prove that the limit of $(1 + 1/(ax))^{bx}$ as $x \to \infty$ is $e^{b/a}$ How to prove one without using the other and any theorem following from them ? Or at least can we prove one of them without the other and the other should follow? | I'm trying to prove that $\frac{\mathrm{d} }{\mathrm{d} x}\ln x = \frac{1}{x}$. Here's what I've got so far: $$ \begin{align} \frac{\mathrm{d}}{\mathrm{d} x}\ln x &= \lim_{h\to0} \frac{\ln(x + h) - \ln(x)}{h} \\ &= \lim_{h\to0} \frac{\ln(\frac{x + h}{x})}{h} \\ &= \lim_{h\to0} \frac{\ln(1 + \frac{h}{x})}{h} \\ \end{align} $$ To simplify the logarithm: $$ \lim_{h\to0}\left (1 + \frac{h}{x}\right )^{\frac{1}{h}} = e^{\frac{1}{x}} $$ ^This is the line I have trouble with. I can see that it is true by putting numbers in, but I can't prove it. I know that $e^{\frac{1}{x}} = \lim_{h\to0}\left (1 + h \right )^{\frac{1}{xh}}$, but I can't work out how to get from the above line to that. $$ \lim_{h\to0}\left ( \left (1 + \frac{h}{x}\right )^{\frac{1}{h}}\right )^{h} = e^{\frac{h}{x}} $$ Going back to the derivative: $$ \begin{align} \frac{\mathrm{d}}{\mathrm{d} x}\ln x &= \lim_{h\to0} \frac{\ln(e^{\frac{h}{x}})}{h} \\ &= \lim_{h\to0} \frac{\frac{h}{x}\ln(e)}{h} \\ &= \lim_{h\to0} \frac{h}{x} \div h\\ &= \frac{1}{x} \\ \end{align} $$ This proof seems fine, apart from the middle step to get $e^{\frac{1}{x}}$. How could I prove that part? |
Define the function $x(t)$ for $t\ge0$: $$ x(0)=1\\ x'(t)=-x(t/2) $$ I could do a power series from $t=0$ like (thanks to @JeanMarie for pointing this old question out), but I ultimately want asymptotic bounds on the excursions as $t\to\infty$, so I don't think the power series helps. Is there any other research on this function? How quickly do these excursions grow with $t$? | I have the following different equation $$f'(x) = f(x/2)$$ with $f(0)=10$. What type of DE is this, and how would you solve it? It seems $f(x)$ is likely to be some relative of $e^x$, since $f'(x) = f(x)$, which is close, but I don't even know what that type of DE is called with that $f(x/2)$ feature, so I'm not having any luck searching for a tutorial. The best candidate I've found was a "delay differential equation", but that seems more suited to $f(x-3)$ than $f(x/2)$. |
I understand that a common feature like zooming can be complicated enough to be , but why can't the site banner zoom too? If the black top bar can be made screen-fit, and the fact that the reputation and badges disappear when zooming suggests that this particular bar is supported, then why can't the site banner be? There are plenty room for the buttons, and I think the HTML element is basic enough to make it easy. Before After Zoom at 133% | On MacBook, I like to zoom using gestures on my trackpad, as described here: With a Multi-Touch trackpad or Magic Mouse, you can tap, swipe, pinch, or spread one or more fingers to perform useful actions. (This is different than zooming with command++ or command+-.) However, when I do this, many hover events don't work right. Like tag hover (and profile popup): Here's a gif: . As I zoom in more, the popup moves further away from where it should be. I also noticed that it breaks SEDE graph hover; nothing happens when I hover over a point. (It should show the Y value.) I am able to see the hover text (as in [description](example.com "hover text")) properly. |
My Desktop PC: Asus P5KC Intel Q6600 2.4GHz 4Gb RAM DDR3 Geforce GT1030 Lubuntu 64bit Geforce GT1030 driver version:- 390.12 I am using the right drivers from Lubuntu but my CPU is at 80% to 100% on YT 4K video On YouTube playing on 4K @60fps I get very high CPU load. I've tried h264ify but it's still lagging with very high CPU load. I tried different Internet browsers including Chrome, Firefox, Opera, and a patched version of Chromium, but the result is the same. I don't have this problem with Windows 10 (64-bit). There CPU usage is 10% or 20% to 30% on YouTube 4K video and all web browsers work excellently, the only problem is memory (RAM). So that's why I tried Lubuntu. Any solution? | My laptop runs Ubuntu 16.04 and has the following specs: SSD 256 i5 7200u 8 gb RAM nvidia Nvidia GeForce GTX 950M So ... it properly plays 30fps 4k video on YouTube, but it freezes when I try to play 60fps 4k video though there was no such an issue with it on Windows 10. I tried different drivers ... and even different browsers ... but it still works properly only on Windows ... but I don't want to go back to Windows! Further Info: After having a conversation with NVIDIA support - it was found out that upon YouTube 4k play - Ubuntu highly uses CPU like on this System monitor screenshot: |
My file Threadout.txt contains like Thread 1/1/25/100 val1=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $1}') val2=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $2}') val3=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $3}') val4=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $4}') for((i=1;i<5;i++)) do val[i]=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $[i]}') echo $val[i] done I have tried this array but not giving the correct result like 1 1 25 100 values. Any error? | How to write the below lines using array?? val1=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $1}') val2=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $2}') val3=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $3}') val4=$(grep 'Thread' Threadout.txt | awk -F"/" '{print $4}') Threadout.txt contains like "Thread 1/1/25/100" |
So I've almost finished a huge project that I have spent hours upon hours creating and now I don't know what to do, I've looked up so many things to try and fix it but none worked as you can see here I have a toy train and when I render it you can see the carriages and they are just black and you cant see anything else and you can see the wheels have put holes in it or something but I don't know what I've done. and an all my other layers when I render it there is nothing. Please help | When I switch to render mode, they show up, and they show when pressing F12, but when clicking the 'Animation' button, nothing shows. If anyone knows how to help, please do. Edit: I have enabled rendering using the cameras, still nothing. Edit #2: What the, some how transferring all of the objects from layer 1-2 does the trick. I guess my camera was set up for the second layer even though it was physically in the 1st. Anyone like to explain? For anyone who's really curious, : Also, it may seem like having the animation length of 1 frame seem bad, but I've done that for other files and they work fine. |
If its true that energy isn't lost, its just transferred, where did the energy go from a falling object that hits the floor and stays there? It started with the most gravitational potential energy, a second before it lands it is converted to kinetic energy, and the kinetic is at the peak. But after it fell and stopped, where is all the energy? Also, it is said you can't create energy. But when an object is at rest on the floor it has no energy, and after being picked up it has energy. I know these are basic questions, but I can't get to the bottom of this. | Kinetic energy conservation in collision. In any type of collision type of collision if we take the system to comprised of both bodies then the net external force is zero. So the work done by external force is also zero. By the relation $W=K_f-K_i$ as $W$ is zero hence kinetic energy is conserved. But this not the case. Can you tell me what is the flaw in my argument? Some people say that the argument has neglected the fact that some kinetic energy is transformed into heat. But heat is created due to the interactions between bodies during collision which is thus an internal force and thus shouldn't affect kinetic energy. |
I'm trying to play music from within a DLL. However, whenever I try this, the PlaySound function does nothing. I've already attempted having the wav file in a resource and I know that the code works as when I compile the DLLMain as a normal main, it plays the music with no problems. The DLLMain code looks like this: if (ul_reason_for_call == DLL_PROCESS_ATTACH) { PlaySoundA("C:\\Sound.wav", NULL, SND_FILENAME); } return TRUE; The strange thing is, I can see that the song is in the program's memory; the memory usage of it goes up to what it should do when it plays a song, but it has no sound. Also, the same code compiled to an exe works perfectly; I can't figure out what's going wrong. UPDATE: It turns out this is because you can't execute lots of things in DLLMain - are there any ways around this? | What is the difference between the three functions and when to use them?? |
Can any of the existing source code analzyers provide metrics on where code is used? I'm trying to find code that is either unused or consumed only by tests, basically candidates for deletion. | What tools do you use to find unused/dead code in large java projects? Our product has been in development for some years, and it is getting very hard to manually detect code that is no longer in use. We do however try to delete as much unused code as possible. Suggestions for general strategies/techniques (other than specific tools) are also appreciated. Edit: Note that we already use code coverage tools (Clover, IntelliJ), but these are of little help. Dead code still has unit tests, and shows up as covered. I guess an ideal tool would identify clusters of code which have very little other code depending on it, allowing for docues manual inspection. |
I've written this function: (function($){ $.fn.loaderHolder = function(action){ var loaderHolder = $(document.createElement('div')) .addClass('loaderHolder'), safeImage = $(document.createElement('img')) .attr("src", "/static/images/icons/vault-bg.svg") .addClass("safe"), lockImage = $(document.createElement('img')) .attr("src", "/static/images/icons/vault-lock.svg") .addClass("lock"), loader = loaderHolder.append(safeImage, lockImage); return this.each(function(){ if(action === "add"){ $(this).append(loader); } else if(action === "remove"){ $(this).children('.loaderHolder').remove(); }; }); }; }(jQuery)); This function generates or deletes a loader. I can run the function like this: $('.foo').loaderHolder('add');. But if I want to add loaders to elements which are dynamically generated, I need to write my code like this: $('.holder').on('click', '.foo', function(){ $(this).loaderHolder('add'); }); I really don't like the anonymous function. Is there any other way to write this without the anonymous function? Thanks! Edit: thanks for all the responses. Edited my code to be correct, forgot the use the parent-selector in the dynamically-generated part. But I was just wondering about a markup something like this: $('.holder').on('click', '.foo', {action: 'add'}, $(this).loaderHolder); I know this is wrong, but is there any way to do it right like this? Or do you just need to anonymous function? | I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off. This happens on page ready and works just fine. The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound. I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option. |
Although I have my own interpretation about representing a random sample using random variables, I am not really sure about it, and I would like to learn others' opinion about this. The question is this: in many books on statistical inference, data or observed sample is represented as $X_1, X_2, \cdots, X_n$ which are $n$ IID random variables. However, it is clear that in real-world, data are numbers with fixed value, not random variables. For example, if I measure heights of $n$ people, then I get $n$ real numbers $h_1, h_2,\cdots, h_n$, not $n$ random variables. Why don't we simply say that these numbers have come from some particular distribution, instead of representing them using random variables? On the same note, how can we talk about things like $\mathbb{V}(X_i) = \sigma$ when clearly a single number has zero variance? Most book seem to ignore these naive questions which students ask, and only define procedures to handle a "sample" given in the form of $n$ random variables. | What do they mean when they say "random variable"? |
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