My question is to coding for a text editor where the operations * 1-append 2-delete k characters from last 3-print nth character 4-undo * Input format is * The first line contains an integer,Q, denoting the number of operations. Each line i of the Q subsequent lines (where 0<=i<=Q) defines an operation to be performed. Each operation starts with a single integer, t (where t is either 1 or 2 or 3 or 4), denoting a type of operation as defined in the Problem Statement above. If the operation requires an argument, t is followed by its space-separated argument. For example, if t=1 and W="abcd" , line i will be 1 abcd. * This is my code #include <stdio.h> #include <string.h> #include <math.h> #include <stdlib.h> #define max 10000  char stack[max],super[max][max]; int top=-1,btop=-1,supert=-1; int bottom=1,qqq=0;  void push(char elem[]) {     //top++;     btop=top;     int i=0;     strcat(stack,elem);     strcpy(super[++supert],stack); }  void pop(int k) {     top=strlen(stack);     for(int i=0;i<k;i++)     {         top--;     }     stack[top]='\0';     /*int i=0;     if(top==-1)     {         strcpy(stack,"");     }     else     {         i=top;         while(i<btop)         {             i++;             stack[i]='\0';         }     }*/     strcpy(super[++supert],stack); }  int main()  {     int tot,op;     scanf("%d",&tot);     int q=0;     for(int i=0;i<tot;i++)     {         scanf("%d",&op);         switch(op)         {             case 1:;                 char elem[max];                 scanf("%s",elem);                 push(elem);                 //printf("%s\n",stack);             break;                          case 2:;                 int num;                 scanf("%d",&num);                 pop(num);                 //printf("%s\n",stack);             break;                          case 3:;                 int k;                 qqq++;                 scanf("%d",&k);                 /*if(qqq%2==0)                 {                     printf("%c\n",stack[k-3]);                 }                 else                 {                     printf("%c\n",stack[k-1]);                 }*/                 printf("%c\n",stack[k-1]);                              break;                          case 4:;                 supert=supert-1;                 strcpy(stack,super[supert]);                 q--;                 //printf("%s\n",stack);             break;         }         q++;     }        return 0; }  For extremely large inputs(operations in the order of 10^5 or 10^6) I am getting segmentation fault Also I could not increase the size of max because if I increase I am getting an error Why is it so?

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.


I am not an electrical engineer but I was just reading the book - The art of electronics. I am just a bit confused about how to analyze this amplifier circuit. In this case, why are R1 and R2 in parallel? I would think it makes more sense for R1 and Rc to be in parallel. Even if that is not the case, when we look into the circuit, shouldn’t there also be a large impedance due to the gain of the transistor? Thanks in advance.

I'm struggling to understand the purpose of the resistor circled in red, I know it has something to do with DC biasing and the feedback on the circuit (as the capacitor will cause AC bypass). But I'm struggling to understand the exact circumstance where this would be needed. Is it a change in supply voltage, or change in transistor beta? And the exact mechanism that would cause the resistor to solve the problem.


Let $x, y ∈ (−2, 2)$ and $xy = −1$. Find the minimum value of $\frac{4}{4-x^2} + \frac{9}{9-y^2} $ ? My Attempt let $t=\frac{4}{4-x^2} + \frac{9}{9-y^2} $ , replacing $y$ by $- \frac{1}{x}$ we get $t=\frac{1}{1-(\frac{x}{2})^2} + \frac{1}{1-(\frac{1}{3x})^2} $ . Using AM-HM inequality we get $t(1-(\frac{x}{2})^2 + 1-(\frac{1}{3x})^2) \geq 2^{2}.$  let $ m =(1-(\frac{x}{2})^2 + 1-(\frac{1}{3x})^2)$ and using AM-GM inequality we get $m \leq 5/3$. But from this point my inequality signs are getting mixed up. Am I on right track?


In my textbook, vector-valued functions is the twelfth chapter, and I would like to be able to make a new document starting from chapter 12. Is there a way I can start the sections in a new document from 12 instead of 1?

\documentclass[11pt,a4paper]{article}     \usepackage[T1]{fontenc}     \usepackage{lipsum}     \usepackage{tocloft}     \begin{document}      \tableofcontents     \thispagestyle{empty}         \newpage      \section{Preface} %want section number to be 0     \thispagestyle{empty}         \pagenumbering{roman}     \lipsum[1-3]     \newpage      \section{Start From Here}     \lipsum[1-5]      \section{And So On...}     \lipsum[1-5]     \end{document}      How do I get section numbering to start at 0?   Edit: I know I can do \section*{Preface}, but that removes it from the ToC, which isn't what I want.


Hi all I am really new to C (just started this week), and want to make sure that I am not looking down the wrong rabbit home and hoping to perhaps get pointed to the right rabbit hole.  I create a struct:  #define MAX 64 #define ARRAY_SIZE 2048  struct object {     int q, c, p;     char name[MAX]; //Stores string up to 63 characters     char arr[ARRAY_SIZE][MAX]; // Creates an array of 2048 cells with string of length 63 max };  int main(){ ... ... int variable = 30; struct object l[variable]; //This is where the crash happens. But only when either variable is too large (for instance works on 15 just fine, but anything over 20 it crashes), or when Array_SIZE is too larger, for instance works fine with 1024 but 2048 crashes. ... ... }   The error I get on crash is the following: Process returned -1073741571 (0xC00000FD) in the cmd window. And the following in the debugger in the IDE: Program received signal SIGSEGV, Segmentation fault. [Inferior 1 (process 12120) exited with code 030000000375]  Am I doing something obviously wrong with how I declare an array of structs? Why would large numbers not work but lower numebrs work?  Does the above error indicate I am accessing something out of bounds somewhere? Ive been up and down the code and cant seem to find any reason why larger numbers dont work and lower ones do. My memory footprint doesnt seem to be the issue, just a few megs of memory.  I need help with what to look for (I cant find any instances of accessing anything out of bounds, so I get the feeling Im not chasing the right rabbit and need to look for something else)? Or maybe Im doing something illegal for C without knowing it?


An example of a symmetry transformation for certain Lagrangians (notably the canonical complex scalar field Lagrangian) is multiplication of the fields by a complex phase. When we multiply the fields by a spacetime-dependent phase and demand that the Lagrangian is left unchanged under the transformation, then we must introduce a new gauge field, and this field is nothing but the photon field, which is a combination of the vector potential A and the scalar potential φ.   Furthermore, from the Lagrangian, we can derive the equations of motion for the fields, and in the example just mentioned, the equations are indeed the Maxwell equations. And since for every symmetry, there is a conserved quantity, the conserved quantity there is electric charge. Can you please explain why it turns out to be electric charge?

Another Noether's theorem question, this time about electrical charge.  According to Noether's theorem, all conservation laws originate from invariance of a system to shifts in a certain space. For example conservation of energy stems from invariance to time translation.  What kind of symmetry creates the conservation of electrical charge?


With the new Android update now avalible, Android has been notifying me each day about updating to the latest version. Each time I press "remind" me later and the notification goes away temporarily. Is there a way to completely remove this reminder?  I am running Android 4.4.4

I upgraded my Nexus 4 to Lollipop a few days ago but I don't like it. I'll leave out my reasons because they're not relevant here. I wiped my phone and installed a clean stock 4.2.2 version instead. I'm happy with this.  Not long after, Android automatically downloaded the 4.3 upgrade and notifies me with the choices "Later" and "Install". I don't want to do this upgrade.  How do I:   get rid of the notification, and  remove the downloaded update (to free up precious storage space).     I have already tried choosing "Later" but the same notification immediately reappears.    Based on Google search results, I also tried going to Settings > Apps > All > Google Services Framework and unticked "show notifications" but it still appears. Force stop or disable also doesn't seem to help, so I've re-enabled the service including notifications. I didn't see any other apps in this list that sounded relevant - did I just not see it?


I am trying to compare a decimal and it seems like bc is ignoring it. The OS is CentOS release 6.9 (Final) and bash is bash-4.1.2-48.el6.x86_64, below is the code  #!/bin/sh i=32.39 IP_LOW_2=32.0 IP_BRD_2=32.254 TEST3=$(echo " ${i} < ${IP_BRD_2} && ${i} > ${IP_LOW_2} " | bc -l ) echo "$TEST3" if [[ $TEST3 =  1 ]]; then echo "Test works!" else echo "Test faied!" fi   I think the outcome should be "Test works!" however its failing, i am tying to figure out what i am missing.   Shell execution results below:  sh -x testing.sh + i=32.39 + IP_LOW_2=32.0 + IP_BRD_2=32.254 ++ echo ' 32.39 < 32.254 && 32.39 > 32.0 ' ++ bc -l + TEST3=0 + echo 0 0 + [[ 0 = 1 ]] + echo 'Test faied!' Test faied!

I have a log file that lists whitelisted IP ranges in this manner:  "217.29.0.0-217.29.255.255", "204.12.0.0-204.12.255.255", "198.54.223.0-198.54.223.255",   I am also working on a bash script which, amongst other things, needs to check this logfile and determine if a specified IP is whitelisted.  In the case of IP 204.12.5.10, for instance, how would I use the log file with the specified ranges to determine whether that IP is part of a range in that file?


This has probably come up before but I did a quick search and didn't see anything on it.  Since the use of highlighting for code specific elements in a question seems to be encouraged, has a UI button for backticks been considered? I imagine this would sit next to the B and I icons in the toolbar.

How do I post text so that it is formatted as code?  What do I need to do so that my code shows up properly — not escaped or removed — when posted? And how to get the correct syntax highlighting?     For more information, see "" in the .


I have a dual boot and I find that the storage is assigned poorly Below are the results of df -h: Filesystem      Size  Used Avail Use% Mounted on udev            7.8G     0  7.8G   0% /dev tmpfs           1.6G  2.2M  1.6G   1% /run /dev/nvme0n1p5   19G   17G  382M  98% / tmpfs           7.8G  466M  7.4G   6% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup /dev/loop1      2.5M  2.5M     0 100% /snap/gnome-calculator/748 /dev/loop2       30M   30M     0 100% /snap/snapd/8542 /dev/loop3      384K  384K     0 100% /snap/gnome-characters/550 /dev/loop5       63M   63M     0 100% /snap/gtk-common-themes/1506 /dev/loop4      218M  218M     0 100% /snap/gnome-3-34-1804/60 /dev/loop6      2.3M  2.3M     0 100% /snap/gnome-system-monitor/148 /dev/loop7       65M   65M     0 100% /snap/gtk-common-themes/1514 /dev/nvme0n1p1   96M   31M   66M  33% /boot/efi /dev/loop8      1.0M  1.0M     0 100% /snap/gnome-logs/100 /dev/loop0       56M   56M     0 100% /snap/core18/1932 /dev/loop9      2.5M  2.5M     0 100% /snap/gnome-calculator/826 /dev/loop10     256M  256M     0 100% /snap/gnome-3-34-1804/36 /dev/loop11      56M   56M     0 100% /snap/core18/1885 /dev/loop12     384K  384K     0 100% /snap/gnome-characters/570 /dev/nvme0n1p7   63G  3.5G   56G   6% /home /dev/loop13      31M   31M     0 100% /snap/snapd/9721 tmpfs           1.6G   16K  1.6G   1% /run/user/121 tmpfs           1.6G   64K  1.6G   1% /run/user/1000 /dev/loop14      58M   58M     0 100% /snap/discord/115 /dev/loop15     163M  163M     0 100% /snap/gnome-3-28-1804/145  As you can see I have >50G in my /home folder but <400M in /. Is there a way to rectify this situation without reinstalling ubuntu?

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I’m blind about integer solutions of a polynomial. I have no number theory background, but I’m curious about how to figure out all integer solutions of a polynomial, for example this question. It is said there are only two solutions, but I can’t give a proof. What I can show is that there are no even solutions. I am actually curious about the general pattern to consider this kind of problem. Can anyone give me some ideas or references? Thanks!

How to solve the Diophantine equation $x^2 + 2 = y^3$ with $x,y>0$ ? ($x,y$ are integers.)


This identity stems from:$$\tan\alpha + \tan\beta + \tan\gamma = \tan\alpha \tan\beta \tan\gamma$$ (for $\alpha + \beta + \gamma = \pi$) which can easily be proven using the $\tan(\alpha + \beta)$ identity.  However, I have been unable to prove $$\sin\alpha \cos\alpha + \sin\beta \cos\beta + \sin\gamma \cos\gamma = 2\sin\alpha \sin\beta \sin\gamma,$$ where $\alpha + \beta + \gamma = \pi$.  EDIT: I proved it. From $\alpha + \beta + \gamma = \pi$ we have$\alpha = \pi - (\beta + \gamma)$ This implies  $$ \sin\alpha = \sin(\beta +\gamma) \quad \text{and }\quad \cos\alpha = -\cos(\beta +\gamma).$$ Then, we have  $$\begin{align} \sin\alpha \cos\alpha &=-\sin(\beta +\gamma)\cos(\beta + \gamma)\\  &= -(\sin\beta \cos\gamma + \sin\gamma \cos\beta)(\cos\beta \cos\gamma - \sin\beta \sin\gamma)\\   &= -(\sin\beta \cos\beta \cos^2\gamma \ - \sin\gamma \cos\gamma \sin^2\beta + \sin\gamma \cos\gamma \cos^2\beta - \sin\beta \cos\beta \sin^2\gamma)\\   &= -[\sin\beta \cos\beta \ (\cos^2\gamma - \sin^2\gamma) + \sin\gamma \cos\gamma \ (\cos^2\beta - \sin^2\beta)]\\   &= \sin\beta \cos\beta \ (\sin^2\gamma - \cos^2\gamma) + \sin\gamma \cos\gamma \ (\sin^2\beta\ - \cos^2\beta ) \end{align}$$ Substituting this in $\sin\alpha \cos\alpha + \sin\beta \cos\beta + \sin\gamma \cos\gamma$ we get  $$\begin{align} \sin\beta \cos\beta &(\sin^2\gamma - \cos^2\gamma) + \sin\beta \ cos\beta + \sin\gamma \cos\gamma \ (\sin^2\beta\ - cos^2\beta) + \sin\gamma \cos\gamma \\  &= \sin\beta \cos\beta \ (\sin^2\gamma +1 - \cos^2\gamma) + \sin\gamma \cos\gamma \ (\sin^2\beta +1 - \cos^2\beta)\\   &= \sin\beta \cos\beta \ (\sin^2\gamma + \sin^2\gamma) + \sin\gamma \cos\gamma \ (\sin^2\beta +\sin^2\beta)\\   &= \sin\beta \cos\beta \ (2\sin^2\gamma) + \sin\gamma \cos\gamma \ (2\sin^2\beta)\\   &= 2\sin\beta \sin\gamma \ (\sin\gamma \cos\beta + \sin\beta \cos\gamma)\\   &= 2\sin\beta \sin\gamma \sin(\beta + \gamma)\\   &= 2\sin\beta \sin\gamma \sin\alpha\\  &= 2\sin\alpha \sin\beta \sin\gamma. \end{align}$$

Prove that $\sin(2A)+\sin(2B)+\sin(2C)=4\sin(A)\sin(B)\sin(C)$ when $A,B,C$ are angles of a triangle   This question came up in a miscellaneous problem set I have been working on to refresh my memory on several topics I did earlier this year. I have tried changing $4\sin(A)\sin(B)\sin(C)$ to  $$4\sin(B+C)\sin(A+C)\sin(A+B)$$ by making substitutions by reorganizing $A+B+C=\pi$. I then did the same thing to the other side to get $$-2(\sin(B+C)\cos(B+C)+\sin(A+C)\cos(A+C)+\sin(A+B)\cos(A+B))$$ and then tried using the compound angle formula to see if i got an equality. However the whole thing became one huge mess and I didn't seem to get any closer to the solution. I am pretty sure there is some simpler way of proving the equality, but I can't seem to figure it out. Maybe there is a geometric interpretation or maybe it can be done using just algebra and trig. Any hint's would be appreciated (I would prefer an algebraic approach, but it would be nice to see some geometric proofs as well)


(a) Using modular arithmetic Show that the equation  $$x^2+y^2+z^2=2xyz$$ has no integer solutions except $x=y=z=0$  (b) Using the results in part (a), show that the equation $$x^3+2y^3+4z^3=0$$ has no integer solutions except $x=y=z=0$  What i tried  For part (a),   At least one of x,y,z is odd. Can it be even? Reduce mod 4  $(even)^2=0 (mod 4)$ $(odd)^2=1 (mod 4)$  implies that LHS = 2 (mod 4)  all 3 are even ie, $x=2x_{1}$, $y=2y_{1}$, $z=2z_{1}$ implies that $$4x_{1}^2+4y_{1}^2+4z_{1}^2$$  (b) I have to somehow reduce the equation of part(b) to something similar to that of part(a).  Equation of part (b)                          $$x^3+2y^3+4z^3=0$$  removing the $x,y,z$ term, we have                           $$x^2+2y^2+4z^2=0$$  and since $x^2$ is even, $x$ is even we have $x=2a$, doing the same for $y$, $y=2b$ and $z$, $z=2c$ we have,the equation  $$(2a)^2+2*(2b)^2+4*(2c)^2=0$$, However im unsure of how to continue from here, could anyone help me with this question, especially part (b). Thanks

Calculate all integer solutions $(x,y,z)\in\mathbb{Z}^3$ of the equation $x^2+y^2+z^2 = 2xyz$.   My Attempt:  We will calculate for $x,y,z>0$. Then, using the AM-GM Inequality, we have  $$ \begin{cases} x^2+y^2\geq 2xy\\ y^2+z^2\geq 2yz\\ z^2+x^2\geq 2zx\\ \end{cases} $$  So $x^2+y^2+z^2\geq xy+yz+zx$. How can I solve for $(x,y,z)$ after this?


There are a variety of editions of D&D published by TSR in parallel to AD&D that get collectively called “Basic D&D”, but the overall relationship of the editions to each other — and which are even separate editions — is not really obvious. It's especially not clear to the uninitiated.   What is the basic overview of these editions that would help someone trying to get a clear grip on these oft-overlooked games?

What are the differences between Holmes, Moldvay, and Mentzer D&D?  Also, which one came first?


Usually, the sentence, "I'm American", is used.  Is it OK if I say,"I'm an American." instead of  "I'm American"? If not, why? What's the difference?

"She’s Mexican. But she’s married to an American."   (Pimsleur English course)


Stella isn't here, did she tell you where she was going? Stella isn't here, has she told you where she was going?  That is, should simple past or present perfect tense be used? It is an exercise from a grammar book and it seems to suggest (I don't have the answer key) that present perfect is the answer as it is also talking about the current status ("Stella isn't here"). But "did you tell" sounds better to me somehow. What do you native speakers think? Thanks!

What's the difference between these two phrases?


So I have a 2-dimensional array in Java where each cell in the array is a Chunk the Chunks hold information about their location. The problem is that in my for loop what seems to be happening is that every time I create a new Chunk I'm just overwriting the information about all the previous chunks here's my code public static int worldsize = 5;  public static Chunk[][] chunks = new Chunk[worldsize][worldsize];  public CreateWorld(){     for(int i = 0; i < worldsize; i++){         for(int j = 0; j < worldsize; j++)         {             System.out.println("creating chunks at postion " + i + ", " + j);             chunks[i][j] = new Chunk(i, j);             System.out.println("chunk at positon 0, 0 : " + chunks[0][0].chunkXPos + ", " + chunks[0][0].chunkYPos);         }     }  }  and here is the Chunk public static int chunkXPos; public static int chunkYPos;  public Chunk(int chunkX, int chunkY){     chunkXPos = chunkX;     chunkYPos = chunkY;     System.out.println(chunkXPos + ", " + chunkYPos);     cells = createChunkList().clone(); }  The expected output would be this: creating chunks at postion 3, 2 3, 2 chunk at positon 0, 0 : 0, 0 creating chunks at postion 3, 3 3, 3 chunk at positon 0, 0 : 0, 0  what I actually get creating chunks at postion 3, 2 3, 2 chunk at positon 0, 0 : 3, 2 creating chunks at postion 3, 3 3, 3 chunk at positon 0, 0 : 3, 2  from what I was able to figure out every time I call = new Chunk(i, j); it sets all the information about all the other chunks as the new coordinates so that's why the chunk at position [0][0] thinks it's at [3][2] The solution is probably very simple, Although I'm new to java and I can't figure it out

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


I came across the problem of correctly aligning a set of boxes in the following TikZ example:    Code  \documentclass[tikz,border=2mm]{standalone} \usepackage{tikz} \usetikzlibrary{positioning, shapes.multipart, backgrounds, fit}  \tikzset{   bluebox/.style={     draw,     rectangle,     minimum height=4cm,     fill=blue!50!white,     align=center,     inner sep=2ex   },   whitebox/.style={     draw,     rectangle,     minimum height=4cm,     fill=white,     align=center,     inner sep=2ex   },   item/.style={     draw,     inner sep=1ex,     fill=white    } }  \begin{document}  \begin{tikzpicture}[font=\sffamily]      % Box 1     \node[whitebox, label={\strut Labelpgq}] (Box1) {\rotatebox{90}{\footnotesize{Something}}};      % Box 2     \node[draw, shape=rectangle split, rectangle split parts=2, fill=white, right=of Box1, label=Options A] (OptionsA) {         \nodepart{one} A         \nodepart{two} B};      \node[draw, shape=rectangle split, rectangle split parts=2, fill=white, below=of OptionsA, label=Options B] (OptionsB) {         \nodepart{one} A         \nodepart{two} B};      \begin{scope}[on background layer]         \node[bluebox, fit=(OptionsA) (OptionsB), label={\strut Labelg}] (Box2) {};     \end{scope}      \draw[dashed] (Box1) -- (Box2); \end{tikzpicture}  \end{document}   As you can see, the box labeled as "Labelg" appears shifted, because the first inner box is anchored as "right=of Box1". However, the alignment couldn't be applied to the respective scope box.  How can I align the box correctly (in line)?, and potentially have two "Options A" boxes next to each other?

I created following figure with a script as pasted below:    \documentclass[tikz,border=2mm]{standalone} \usepackage{tikz} \usetikzlibrary{positioning, shapes.multipart, arrows, shadows, backgrounds, fit}  \tikzset{   bluebox/.style={     draw,     rectangle,     minimum height=4.5cm,     fill=blue!50!white,     align=center,     inner sep=2ex   },   whitebox/.style={     draw,     rectangle,     minimum height=4.5cm,     fill=white,     align=center,     inner sep=2ex   },   item/.style={     draw,     inner sep=1ex,     fill=white    },   matrix/.style={     draw,     fill=white,     text centered,     minimum height=1em,     drop shadow   } }  \begin{document}  \begin{tikzpicture}[font=\sffamily]      % Stage 1     \node[whitebox, label={Labela}] (Stage1) {\rotatebox{90}{Something}};      % Stage 2     \node[whitebox, right=of Stage1, label=Labelpgq] (Stage2) {\rotatebox{90}{\footnotesize{Something}}};      % Stage 3     \node[draw, shape=rectangle split, rectangle split parts=2, fill=white, right=of Stage2, label=Options A] (OptionsA) {         \nodepart{one} A         \nodepart{two} B};      \node[draw, shape=rectangle split, rectangle split parts=2, fill=white, below=of OptionsA, label=Options B] (OptionsB) {         \nodepart{one} A         \nodepart{two} B};      \begin{scope}[on background layer]         \node[bluebox, fit=(OptionsA) (OptionsB), label=Labelg] (Stage3) {};     \end{scope}      \draw[dashed] (Stage1) -- (Stage2);     \draw[dashed] (Stage2) -- (Stage3); \end{tikzpicture}  \end{document}   Here are the issues I want to solve:   When labels contain a "p", "g" or "q", the text has a larger distance. It looks like the padding is given by the lowest pixel (bug?). For some reason, the blue box is shifted. It should be on level with the others. I experimented by applying "right=of Stage2" to the blue box, but without success.   I'm thankful for help here.


The word "uroboros," coming ultimately from Greek, has a couple of spellings and also pronunciations (see ). As explained by Nohat in the linked page, the  are the following:  /ɔːˈrɒbɔrəs/ /jʊərɵˈbɒrəs/   lists only /ˌjʊərə(ʊ)ˈbɒrəs/ for "uroboros," and states that the word was first used in English around the 1940s. , for "ouroboros," lists yet another set of pronunciations, oddly enough:  /ˌuːrəˈbɒrəs/ /uːˈrɒbəˌrɒs/  So in one sense, it almost seems a free-for-all. However, there's one pronunciation that seemed natural to me but that I never see listed: /jʊəˈrɒbɔrəs/, with antepenultimate stress. Here's why I'd expect this pronunciation. . The stress in Greek is on the penult, but there's a short /o/ in the penultimate syllable, so I'd expect a Latinized pronunciation of /uˈroboros/ according to the , and I'd also expect for the Latin stress position to carry over to the English word, especially when the initial vowel uses the value /jʊə/ associated with the . Compare to "automaton," another example of a Greek word with a short vowel in the penult that is stressed on the antepenult in English. But, I've never seen this pronunciation listed. Dictionaries do list pronunciations with antepenult accent, and pronunciations with initial /j/, but none I can find list a pronunciation with both of these features combined. So, if I use it, am I just adding my own idiosyncratic pronunciation to the mix, no better and no worse than the other variants? Or is there some flaw in the analogy I made above that makes /jʊəˈrɒbɔrəs/ a solecism, but that justifies /jʊərɵˈbɒrəs/ (or /ɔːˈrɒbɔrəs/, etc.) ?  :  In words of three or more syllables, stress falls either on the penult or the antepenult (third from the end), according to these criteria:  If the penult contains a short vowel in an open syllable, the stress falls on the antepenult: e.g. stá.mi.na, hy.pó.the.sis. If the penult contains a long vowel; a diphthong; a closed syllable (with any length of vowel); or is followed by z, the stress falls on the penult.  [...] The fact that decorum is stressed on the penult, and exodus on the antepenult, is a fact about each of these words that must be memorized separately (unless one is already familiar with the Classical quantities, and in the former case, additionally with the fact that decus -ŏris n. with short -o- syllable became in late Latin decus/decor -ōris m. with long -o- syllable: 'Dómine, diléxi decórem domus tuæ').  Does anyone know if the pronunciation of "uroboros" might be explained in the same way as that of "decorum," where the vowel length/stress shifted at some point in Latin? Was "uroboros" or "ouroboros" even used in Latin? I've already searched out attested English pronunciations, so I don't want an answer that just repeats these (although I would appreciate learning about any additional pronunciations listed by reputable dictionaries). What I'm concerned with now is the pattern behind them, possible etymological bases for the English pronunciation, and orthoëpic advice, in particular about the hypothetical pronunciation /jʊəˈrɒbɔrəs/.

I have been studying the pronunciation of Greek-derived words in English, and I've found an odd anomaly. There are (at least) two possible pronunciation patterns for plural word-forms that end in -mata (which correspond to singular word-forms that end in -ma).   Antepenult stress (expected)  It appears that it is always possible to place the stress on the antepenult (third-to-last) syllable, such as:    /ˈlɛmə/, /ˈlɛmətə/  /ˈskiːmə/, /ˈskiːmətə/  /ˌtɛrəˈtoʊmə/, /ˌtɛrəˈtoʊmətə/~/ˌtɛrəˈtɒmətə/  /ˈstɪɡmə/, /ˈstɪɡmətə/   This is what would be expected from  (I believe most or all of these words came through Latin before entering English), since the penultimate "a" in the original Greek words is short.  Maybe Latin vowel quality and stress rules are not very relevant; certainly, few English speakers know about them nowadays. And even with antepenult stress, some of these pronunciations do not seem to follow all of the traditional rules for pronouncing Latin-derived terms in English. I was reminded by some comments in this  that  in antepenult stressed syllables, we would expect tense ("long") vowels to be shortened due to  (TSL), yielding pronunciations like /ˌtɛrəˈtɒmətə/ (which I just noticed is in fact listed in the Oxford English dictionary) and ?/ˈskɛmətə/ (which is not). (Compare to genus~genera /dʒiːnəs/~/dʒɛnərə/, and perhaps opus~opera /oʊpəs/~/ɒpərə/). However, there are other Latinate plural forms that typically don't have trisyllabic laxing (matrices, also I think helices), or where both the lax- and tense-voweled pronunciations coexist (codices, apices), so I guess the apparent lack of it in schemata should not be surprising. (There are even some exceptions to TSL in singular nouns like obesity.)  Penult stress (unexpected)  The other pronunciation seems to exist only for a couple of words, in which the penultimate "a" is commonly stressed and broadened: stigma ~ stigmáta  (listed by both the Merriam-Webster dictionary and the ), and also sometimes schéma ~ schemáta /skiːˈmɑːtə/ (listed only by the ). (Neither the Merriam-Webster dictionary nor the Oxford Learner's Dictionaries list *"lemmáta").  I'm wondering why this pronunciation exists. It's an irregular plural either way, and putting the stress on the penultimate syllable creates a stress change between the singular and the plural forms.  (It's true that all of these words are rare, and some people might pronounce some of their plurals differently. The pronunciations I give here are simply the ones listed in dictionaries.)  The plural form "stigmata" is probably most common in religious or theological contexts (where it refers to the wounds of Christ), so at first I wondered if the penultimate stress was supposed to be closer to the original Greek pronunciation, but according to , the stress is on the antepenult in Greek as well.  So, what's up with this? Did the stress perhaps change in Latin over time, is this a tradition of Greek accentuation that I'm not familiar with, is this a simple matter of ignorance of the original position of the stress that has now become entrenched with time and usage, or is this somehow explainable by established English stress patterns? (For example, do English speakers have some natural preference for a penultimate stress on polysyllabic words?)  If nobody knows of a reason, I suppose I can just put it down to people encountering the word mainly in text, not knowing which syllable to stress, and choosing the penult because it sounds better to them.  (I asked this question a while back on , but nobody knew of any reason.)


In the quantum mechanics, the Hamiltonian $H$ satisfies the Schroedinger equation $$ H\psi = E\psi. $$ Suppose that $P$ is a projection operator, and $Q=1-P$. The low-energy effective Hamiltonian is $$ H_{eff} = H_{PP} + \frac{H_{PQ}H_{QP}}{E-H_{QQ}}. $$ My method to do so is a combination of two algebraic equations. Recently, I found a good (L. Petersen $et~~al.$ A simple tight-binding model of spin–orbit splitting of sp-derived surface states), whose authors declared that one can obtain (EQ. 13) $$ P\frac{1}{\epsilon-H}P = \frac{1}{\epsilon-H_{eff}} $$ from a standard theorem in linear algebra. Here, I just wonder that "what's the standard theorem"? Please inform me of the omited detail in the above paper.

In order to find the effective Hamiltonian in a subspace which is energetically well separated from the rest of the Hilbert space people try to find a unitary transformation which makes the Hamiltonian block-diagonal in that subspace. Usually this procedure is done perturbatively and the corresponding formulae -usually to second order- is available. But I saw somewhere that the effective Hamiltonian satisfies the compact relation : $$ \frac{1}{E-H_{eff}}=P_s \frac{1}{E-H} P_s$$  Where $P_s$ is the projection operator into the subspace which we want its effective Hamiltonian.   So where does the above relation come from? Also it will be very helpful if you mention some references about about different ways of obtaining effective Hamiltonian systematically.   I saw the above formula in the book "Interacting Electrons and Quantum Magnetism" by Auerbach.


I'm new but slowly getting situated to Linux/Ubuntu and I'm finding Nautilus to be pretty but lacking. I was wondering if you guys could recommend a file manager that:  Can show tree view Has individual folder options. Like, for my photos folder I want to see extra large thumbnails rather than icons, with list view everywhere else. Option to see the actual address/path, rather than the path address set as default in Nautilus. Modern-looking. No win98 GUIs please!  Basically ... something that'll mimic Windows 10 lol ... Thanks in advance.

Which Linux file manager has a UI that mimics Windows File Explorer in a way that it supports a split view with:  a directory tree on the left, and a file list on the right?


The "top 10% overall" link goes to this URL:    which is a 404 error.

Clicking on the rep league lines that read like "top 2% this quarter" returns a 404 page. Example in point:  This report is split off as per request of Adam Lear from


evebody... today, I want to install Ubuntu 12.04 X64 in my ASUS X45A notebook.  I prefer X64 cuz in the notebok's Driver CD, it say's "Support with Windows 7 64 bit only!" and i'am afraid something won't work if i installed the X32 OS.  And when i installing the Ubuntu directly from Windows 7 (i can't boot into Pendrive cuz my netebook doesn't recognize it, help needed too) i got this error message >> "Could not retrieve the required disk image files"  and here is the Wubi error log >>   I'm new to Ubuntu.. so please, help me... i'm planning to use Ubuntu cuz it's easier to developing Android Apps... whoever wants to help me, i really appreciate that :)

I tried to install Ubuntu 12.10 with the Wubi installer while running Windows, because my PC does not accept my BootCD as a bootable medium.  But Wubi showed me this error:  Ubuntu-Installationsprogramm (X) Ein Fehler ist aufgetreten: Could not retrieve the required disk image files Weiter Informationen finden Sie in der Protokolldatei: c:\users\username\appdata\local\temp\wubi-12.10-rev273.log   What can I do, because I want to get rid of my Windows 7 and use the way better Ubuntu 12.10?  Thanks for your huge answer, now my next problem after trying to install wubi with the .iso is, that the same error shows up again and i am not shure which part of the errorreport you need.  Can you tell me? Because i'm not that good at linux.


In this post-apocalyptic short story, a small group of people are returning from a (failed) effort to save one outpost.  They cross a snowy wasteland to find that the nearest domed refuge has also ceased functioning and are forced to stretch their supplies and physical resources to reach a farther afield one.  The story ends with them barely reaching their goal to find a warm and civilized society inside the refuge. I believe hot cocoa features in the final scene.

It's not All Summer in a Day.  This was a story about explorers on Venus, who are separated from their base (possibly they're lost, possibly they suffered equipment failure, possibly they're just traveling from base to base) and are slowly being driven insane because it never stops raining.  The story is old enough that Venus' clouds were still believed to indicate a wet climate.  I can't remember much more detail than that.  I have the impression that the narrator at one point either dreamed of or fantasized about walking into the destination base and being handed a very plush towel to dry off.  I can't remember the central plot points - only the (very wet) setting.  I would have read this in the late 1970's or early 1980's.  I thought it might be an H. Beam Piper short story but I've been through his catalog and don't see any likely suspects.


Solve the following difference equation to the specific $x$ values  $x_0 = 2$ $x_1 = 5$ $x_n-4x_{n-1}+3x_{n-2}=0$   I need some help and guidance to get this problem started and to understand the proper way to solve these equations.

Q1. Find the general solution to the difference equation  $$ a_{n} - 4a_{n-1} + 3a_{n-2} = 6 $$    Q2. Solve the difference equation   $$ a_{n} - a_{n-1} - 2a_{n-2} = 0, a_0 = 2, a_1 = 4 $$    I am completely lost in solving recurrence relation questions. Can anyone guide me in steps to solve the following 2 questions?


Example:  There is a bit of wine left in the glass.

Is it correct to say, "a bit of water" or should it be "a drop of water"?  More generally, can the word "bit" be used to describe a small quantity of a liquid or can it only be used for solids?


names is a table that maps every unique name to an id:  CREATE TABLE names (   name       VARCHAR(20)    NOT NULL,   name_id    INT            NOT NULL AUTO_INCREMENT,   PRIMARY KEY (name),   UNIQUE (name_id) ) ENGINE=InnoDB   If 'foobar' is already stored in names, I want to get its name_id. Otherwise I want to store it and get the name_id that was generated for it.   How does one do this, dealing with the possibility of two threads racing to add 'foobar'? (Note: we never delete from this table.)  With myISAM I wrote:  GET_LOCK('foobar'); SELECT name_id FROM names WHERE name = 'foobar'; if name wasn't found     INSERT INTO names SET name='foobar';     SELECT LAST_INSERT_ID(); -- that is, name_id RELEASE_LOCK('foobar');   However, I'm very unclear about how to achieve this using transactions and row-level locking in innoDB.  UPDATE: mySQL requires that AUTO_INCREMENT only be used for the PK. I'm using MariaDB, which only requires that the AUTO_INCREMENT column be defined as key. Updating example accordingly.

How do you stop race conditions in MySQL? the problem at hand is caused by a simple algorithm:   select a row from table if it doesn't exist, insert it   and then either you get a duplicate row, or if you prevent it via unique/primary keys, an error.  Now normally I'd think transactions help here, but because the row doesn't exist, the transaction don't actually help (or am I missing something?).  LOCK TABLE sounds like an overkill, especially if the table is updated multiple times per second.  The only other solution I can think of is GET_LOCK() for every different id, but isn't there a better way? Are there no scalability issues here as well? And also, doing it for every table sounds a bit unnatural, as it sounds like a very common problem in high-concurrency databases to me.


Let $n$ be a natural number. How do you prove that   $$ \lfloor n/1 \rfloor+ \lfloor n/2\rfloor+ \lfloor n/3\rfloor+\dots +\lfloor n/n]+\lfloor \sqrt{n}\rfloor$$  is even? Thanks.

Let $n$ is a natural number. Prove that $$\left\lfloor\frac{n}{1}\right\rfloor+\left\lfloor\frac{n}{2}\right\rfloor+....+\left\lfloor\frac{n}{n}\right\rfloor+\left\lfloor{\sqrt{n}}\right\rfloor$$   is even.   I used induction and the inequality $$x-1<\lfloor{x}\rfloor\le{x}$$ to prove it.  Is there any other, nicer way to do it?


I'm getting this error:      Unable to start activity   ComponentInfo{amsi.dei.estg.ipleiria.pt.ima/amsi.dei.estg.ipleiria.pt.ima.ListaEmpresas}:   java.lang.NullPointerException: Attempt to invoke virtual method 'void   android.database.sqlite.SQLiteDatabase.execSQL(java.lang.String)' on a   null object reference" on this line in my DBHelper:   The error is in this line:  database.execSQL(createEmpresasTable);   My DBHelper:  public class ImaBDHelper extends SQLiteOpenHelper {  private static final String DB_NAME = "IMA"; private static final int DB_VERSION = 1;  private static final String EMPRESAS_TABLE_NAME = "empresas"; private static final String NOME_EMPRESA = "nome"; private static final String DESCRICAO_EMPRESA = "descricao"; private static final String LOCALIDADE_EMPRESA = "localidade"; private static final String AREA_EMPRESA = "area";  private final SQLiteDatabase database;  public ImaBDHelper(Context context) {     super(context, DB_NAME, null, DB_VERSION);      this.database = getWritableDatabase(); }   @Override public void onCreate(SQLiteDatabase db) {     String createEmpresasTable = "CREATE TABLE " + EMPRESAS_TABLE_NAME +             "(id INTENGER PRIMARY KEY AUTOINCREMENT," +             NOME_EMPRESA + " TEXT NOT NULL," +             DESCRICAO_EMPRESA + " TEXT," +             LOCALIDADE_EMPRESA + " TEXT NOT NULL," +             AREA_EMPRESA + " TEXT NOT NULL," + ")"; database.execSQL(createEmpresasTable); }  @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {     String sql = "DROP TABLE IF EXISTS " + EMPRESAS_TABLE_NAME;     database.execSQL(sql);     this.onCreate(database); }   The rest are just methods to create, read, update and delete.  Sorry if this is a duplicate but I haven't found the answer for this exact problem in my searches. Thank you in advance!

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Hi i am searching for a way to change the active theme when the site is on maintenaince mode (Drupal 7), can you help me? thanks in advice

What would be the best practice for theming the maintenance mode page in Drupal 7?


I was just looking through the list of Stack Exchange sites, and the row for  looks a little messed up.  It's pretty impressive to get 14 questions per day from zero visitors, although it's a fair bit less impressive to still have zero visitors per day after being active for 2013 years and eleven months. I'm assuming that these are the same problem, and the property for the site starting date is still set to the default value of DateTime, which is, or January 1, 0001 at 00:00.

I took this screenshot just now, and  about the new . I refreshed the page, went back, and nothing changed.    And, here's what I find odd:  It clearly isn't almost 2014 years old. That's more likely when it was started.  How can there be 8.7 questions a day, while there are 0 visits a day? That's kind of impossible.   I'm hoping here that it's not just me. I know very limited Japanese, not even enough to hold a conversation with a toddler. I'm merely observing.


I am trying to make a shop. This is my code but it's not working  /execute as @a unless entity @s[team=blue,nbt={Inventory:[{id:"minecraft:diamond",Count:2b}]}] unless entity @s[team=blue,nbt={Inventory:[{id:"minecraft:diamond",Count:1b}]}] unless entity @s[team=blue,nbt={Inventory:[{id:"minecraft:diamond",Count:3b}]}] if entity @s[team=blue,nbt={Inventory:[{id:"minecraft:diamond"}]}]   Expanded:  /execute as @a     unless entity @s[team=blue,nbt=     {         Inventory:[{id:"minecraft:diamond",Count:2b}]     }]     unless entity @s[team=blue,nbt=     {         Inventory:[{id:"minecraft:diamond",Count:1b}]     }]     unless entity @s[team=blue,nbt=     {         Inventory:[{id:"minecraft:diamond",Count:3b}]     }]     if entity @s[team=blue,nbt=     {         Inventory:[{id:"minecraft:diamond"}]     }]   What that is supposed to do is give an output when you have at least 4 items. It just doesn't work.

I am using the AmazingKit plugin on my Minecraft server to make inventory kits for players. In a command block I have the following command:  /tellraw @p ["",{"text":"Iron","clickEvent":{"action":"run_command","value":"_____"}},{"text":" / "},{"text":"Gold","clickEvent":{"action":"run_command","value":"_____"}}]   Which prints the following result: Iron / Gold.  When a player clicks on Iron, what command should I write where the empty space is _____ in order to check if the player has at least (>=) 20 iron ingots in his inventory and if he/she does, remove 20 iron ingots and execute /kit Basic. If the player has less than 20 iron ingots in inventory, the command won't be executed. Instead, Insufficient amount of iron ingots will be printed out.   Same applies when a player clicks on "Gold".  I'm on 1.14 version


guys very simple question here.  I'm writing a paper on elliptic curves, and the domain of the function has this extra point which is referred to as "a point at infinity."  It looks like this :  I have no clue what the shortcut is for that.  I've just been using the letter O instead.  Anyone know what that symbol is?  Appreciate the help!

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


NewViewController_iPhone *newViewController = [[NewViewController_iPhone alloc] initWithNibName:@"NewViewController_iPhone" bundle:nil];   [self.navigationController pushViewController:newViewController animated:YES];   viewWillAppear: and viewDidAppear: are not called in NewViewController_iPhone. Why not?

I've read numerous posts about people having problems with viewWillAppear when you do not create your view hierarchy just right. My problem is I can't figure out what that means.  If I create a RootViewController and call addSubView on that controller, I would expect the added view(s) to be wired up for viewWillAppear events.   Does anyone have an example of a complex programmatic view hierarchy that successfully receives viewWillAppear events at every level?  Apple's Docs state:     Warning: If the view belonging to a view controller is added to a view hierarchy directly, the view controller will not receive this message. If you insert or add a view to the view hierarchy, and it has a view controller, you should send the associated view controller this message directly. Failing to send the view controller this message will prevent any associated animation from being displayed.   The problem is that they don't describe how to do this. What does "directly" mean? How do you "indirectly" add a view?  I am fairly new to Cocoa and iPhone so it would be nice if there were useful examples from Apple besides the basic Hello World crap.


other questions about cashless society of humans but this seems to have been due to a philosophical change. but is it implied that technology makes it possible for all to have food and shelter even without working?

I have noticed that guest quarters on the Enterprise D have fruit bowls on their tables.  A prominent instance is the fruit bowl in Berlinghoff Rasmussen's quarters in "".  The first thing that Rasmussen does when Data takes him to his guest quarters is take a piece of fruit and shove it in his pocket.  Who replicates fruit for these fruit bowls before guests arrive?  More generally, who removes unused fruit and tidies quarters after guests leave?  Is there a ship hospitality staff, perhaps including Guinan's wait staff in Ten Forward?


I just visited  and for me it shows no results. Has something broken?   The problem occurs for me , but oddly not on some other sites I've tried, such as  or .   I have tried pressing Ctrl+F5 many times, but as yet no success in solving this. This has now been broken for days, leading me to believe that caching is not the culprit.  I've since noticed that the problem goes away if I add some tags as favourites (e.g. ). But I prefer to have no favourite tags, so the problem remains for me. What's odd is that I don't use favourite tags anywhere on the network, so the fact that the ServerFault and Programmers tab works for me is a mystery.

I wanted to look for some questions to answer, so I went to . It came up with some really weird tags, as seen in this image:        , , , , and  are the tags in which I have the most posts. I also have  that has the tags , , and .  When I clicked on |bug|reputation|achievements-dialog|:        After I gave myself a favorite tag it acted as normal filtering the unanswered questions by that tag.


Which package to use to get a content pane in the PDF file. I have attached a pic to show what I mean.

I'm using MiKTeX and using pdfLaTeX. I can generate the PDF, but there are no bookmarks. In the .tex-file it is using:  \chapter \section \subsection   (with labels)  I originally used make with sphinx to output LaTeX. It must work somewhat or I wouldn't get the PDF. When I say bookmarks, I mean when you are in Acrobat and the left side has the Bookmarks panel.  I am reading   But I am not sure where to apply this.  EDIT:  I applied this, \usepackage{bookmark}, and got bookmarks, but I never get the subsection bookmarks.


I have been researching the harmonic series, $H_k$ and the Euler-Mascheroni constant, $\gamma$, quite a bit recently. I understand that the diagamma function has this property: $$\psi^{0}(k+1) + \gamma = H_k$$  And equivalently, $$\frac{d}{dk}[ln(k!)] + \gamma = H_k$$ My question is, does there exist some $f(k)$ such that  $$f(k) + \gamma = H_k$$ where $f(k)$ does not require the use of special functions like $\psi$? This question is motivated by the fact that other sums have a formula for the partial sums, for example $$1+2+3+...+n=\frac{n(n+1)}{2}$$ I see how the sum of natural numbers up to $n$ is different than $H_n$; the former always has solutions in $\mathbb{N}$ and the latter (excluding $H_1$) always has solutions in $\mathbb{Q}$. Can $H_n$ have a coinciding formula only using elementary functions, and if not, why?

One of the joys of high-school mathematics is summing a complicated series to get a “closed-form” expression. And of course many of us have tried summing the harmonic series $H_n =\sum \limits_{k \leq n} \frac{1}{k}$, and failed. But should we necessarily fail?      More precisely, is it known that $H_n$ cannot be written in terms of the elementary functions, say, the rational functions, $\exp(x)$ and $\ln x$? If so, how is such a theorem proved?    Note. When I started writing the question, I was going to ask if it is known that the harmonic function cannot be represented simply as a rational function? But this is easy to see, since $H_n$ grows like $\ln n+O(1)$, whereas no rational function grows logarithmically.  Added note: This  asks a similar question for “elementary integration”. I guess I am asking if there is an analogous theory of “elementary summation”.


gives an answer about provoking opportunity attacks when wielding a dagger and a whip.   I am interested how this interacts with the feat War Caster (5e PHB p170):     When a hostile creature's movement provokes an opportunity attack from you,    you can use your reaction to cast a spell at the creature, rather than    making the opportunity attack.   The reason is that the reach property of the whip is only valid if the weapon itself is used for the opportunity attack.  Do I get an opportunity attack with a spell when a creature leaves a square   adjacent from me (i.e. leaves dagger reach)? 5ft away from me (i.e. leaves whip reach)?   Please give an answer according to the RAW, and specifically mention either 's interpretation as basis, or answer for both.

Assume I wield a Whip in one hand and a dagger in the other.  If a creature moves from 5ft to 10ft it has technically moved out of my reach (dagger), but at the same time it is still inside my reach (whip). When does it provoke opportunity attacks from me?  I am fully aware that this would not enable me to make off-hand attacks since the whip is not a light weapon, just to cut that issue out of the question.


I got stuck at the following physics question :     A particle has initial velocity,$\mathbf v = v_x \hat i +  v_y \hat j $ m/s and a constant force $\mathbf F = F_x \hat i +  F_y \hat j$$ acts on the particle. The path of particle will be?   My approach is that $$ \mathbf x = v_x t+ \frac{F_x}{2m} t^2$$ and $$ \mathbf y = v_y t+ \frac{F_y}{2m} t^2$$. But I don't know how to substitute $t$ from those equations. So what should I do now?   Thanks in advance.

Show that the following system of parametric equations describes a line or a parabola: $$\begin{cases} x=a_1t^2+b_1t+c_1 \\ y=a_2t^2+b_2t+c_2 \end{cases}, t\in\mathbb{R}.$$


We are given the following experiment:  Consider an experiment which is a Bernoulli trial: it either succeeds with probability p or fails with probability 1− p; trials are independent of one another. Throughout this question we specify a null hypothesis H0 : p = 1/ 2 , and an alternative hypothesis HA : p = 2/ 3 . We perform the experiment 50 times, and our observation is r = 33 successes and 17 failures. Only one-sided tests are considered here.  We are asked to give a precise definition of the p-value. I don't understand what the question is asking really but I attempted it.  Attempt:  > dbinom(33,50,0.66) [1] 0.1184165]  Our p-value is greater than 0.5 meaning we reject the null hypothesis.   Am I answering the question correctly or did I misunderstand the question entirely?

After taking a statistics course and then trying to help fellow students, I noticed one subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests.  It seems that students easily learn how to perform the calculations required by a given test but get hung up on interpreting the results.  Many computerized tools report test results in terms of "p values" or "t values".  How would you explain the following points to college students taking their first course in statistics:   What does a "p-value" mean in relation to the hypothesis being tested?  Are there cases when one should be looking for a high p-value or a low p-value? What is the relationship between a p-value and a t-value?


Good day everyone.  I am an Architect who primarily works in Archicad, Revit and SketchUp. I recently started to learn my way around Blender as I would like to use it as an Architectural visualization tool.  I can export a building from Archicad just fine, import it into blender, apply materials, lights etc. just fine and render it.   The problem I'm running into is that whenever I have to make changes to the Archicad model I don't know how to go about re-importing the updated CAD file to blender without having to redo everything in blender ( materials, lights etc.)  Is there a way to do this in Blender similarly to programs like Lumion and Artlantis?  Regards,  Hanrich

I normally use Octane render, both standalone and plugin version for Sketchup. I'm not at all an hardcore user. I'm trying out Blender in my freetime, just for fun.  When I use the standalone version of Octane, I normally export my sketchup model as obj, and link this file into Octane Render, with it's own node. When I make changes in Sketchup (or Gravity Sketch) I export again as obj and simply press a reload icon in Octane, and the model is updated.   I can't figure out how to do this in Blender. I have only found out how to import, but not link / refresh geometry.   Is it not possible or am I'm looking in the wrong part of Blender?


Let $G$ be a group and let $N$ and $K$ be normal subgroups of $G.$ Suppose $N \cap K = \{e_G\}$. Prove that for all $a \in N$ and $b \in K, ab = ba.$   I am seeing that all normal subgroups are not necessarily abelian so I am not sure what tools to use for this one.

Suppose $G$ is a group and $H,K \trianglelefteq G$. If $H \cap K =1$ the $hk=kh$ for all $k \in K, h \in H$?  Here is what I have so far:  Take $h \in H$ and $k \in K$ we wish to show $hk=kh$ or equivalently $hkh^{-1}=k$. Now I know $hkh^{-1} \in K$ since $K$ is normal in $G$ but I don't know how to show that $hkh^{-1}=k$ i.e. it is the element we want it to be not some other element of $K$. I haven't used the fact that $H \cap K=1$ yet so I guess it follows as a consequence of that but I'm not seeing how at the moment.


I've found out that there is no "Sign Out" link on the Site. Looked at bottom and top and all over the page. Nor it is present in the user page.  Where is it? It would be useful if present besides the "username" on the top of the page.

Took a few seconds to find how to get back to chat on SO. I quickly found that it was hiding inside the StackExchange drop down along with Blog and Log out. Having these links inside the "site switcher" seems a tad out of place and calls for concern personally.   Any ideas for an alternative to these objects location?


Let $X\subset\mathbb{R}$ is convex and $f:X\rightarrow\mathbb{R}$ is a twice continuously differentiable function. Is $f(X)$ convex?

How to prove: Continuous function maps compact set to compact set using real analysis?  i.e. if $f: [a,b] \rightarrow \mathbb{R}$ is continuous, then $f([a,b])$ is closed and bounded.   I have proved the bounded part. So now I need some insight on how to prove $f([a,b])$ is closed, i.e. $f([a,b])=[c,d]$. From Extreme Value Theorem, we know that $c$ and $d$ can be achieved, but how to prove that if $c < x < d$, then $x \in f([a,b])$ ?  Thanks!


I'm buying a used iPad 2 through Craigslist.  He has lost his iCloud account info for that iPad 2. If he does a factory reset on the iPad 2 and I bought it after reset, would it be possible during set up.   Can I use my own iCloud info to go forward and pass through, on the set up of the iPad 2 once I bought it from that person?

I bought a used iPhone 4.  The previous owner re-set the phone, but did not remove the device from their iCloud.  It is asking me for their iCloud information when I try to set-up the phone.  I don't have contact with the previous owner anymore.  Is there a way to remove the device from their iCloud so I can use a new one?


Assume $f:\mathbb R\to \mathbb R$ is uniformly continuous function and has a right derivative $f'_+:\mathbb R\to \mathbb R$ which is also uniformly continuous. Where $f'_+$ is define by  $$f'_+(x) = \lim_{h\to 0^+}\frac{f(x+h)-f(x)}{h}$$     Prove or disprove that $f$ is differentiable.

A book of mine says the following is true, and I am having some trouble proving it. (I've considered using the Lebesgue differentiation theorem and absolute continuity, as well as elementary analysis methods.)     Let $f: [0, \infty) \rightarrow \mathbb{R}$ be continuous and have right derivatives at each point in the domain, with the right derivative function being continuous.  Then $f$ is differentiable.


I printed my report, but I saw that it has the same big space around the content for every page. How can I change it?

I've read that—unless I know a lot about typesetting—I shouldn't change the margins of a LaTeX document. The default margin size of the article class is really big and it feels like a lot of space is waste. Thanks to the geometry package, it is simple to change the margins, but I'm not sure if I should.  Can someone tell me why the default margin size is so big? Also, why shouldn't I change the margin size?


so i have these two objects, which are structurally basically the same. If i select the first object, tab into edit mode, select the highlighted edgeloops (shown on the left), and add a bevel with Ctrl + b with the shown settings, I get the result on the right. Now, if i tab out of edit mode, select the second object, and apply the same procedure with the same settings, I get the result on the right, as you can see, the results are different. Now, in object mode, if I had selected the second object first and first object second, hit Ctrl + J to join them, tab into edit mode, and apply the procedure again, I would've gotten this in this case, the result is similar to that of the first object. If i select the second object first and first object second when joining the objects, the result is reversed:     Any idea why this is? Both of them are simple objects made using the same procedure.  thanks!

I was trying to model a desk and came across a problem, I can't seem to solve. I wanted to create a simple bevel. I used Mesh > Edges > Bevel on a selected edge and got this result   Why is it not symmetrical? How can I make it symmetrical?  For reference, what I actually wanted:


Last night my internet connection was slow so I canceled Gimp installation (4.5 Mb/53Mb). But today when I try to click on Gimp install button in Ubuntu Software Center, this error came up "Requires installation of untrusted packages". What should I do now?

Any install that I'm trying through the Software Center is telling me:  Requires installation of untrusted packages: The action would require the installation of packages from not authenticated sources.  I did an apt-get update from the command line, then removed the software sources that the keys were bad from (PPAs I added myself), and unchecked them in the software sources for software center, but to no avail.  I can't install anything from software center anymore - only> from the command line with apt-get. Is uninstalling/installing the only option?  I don't want to break other PPAs that I have. Additional information: Here's a paste from apt-get update: Reading package lists... Done W: GPG error: http://ppa.launchpad.net oneiric Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B725097B3ACC3965 W: GPG error: http://us.archive.ubuntu.com oneiric Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>  I've tried apt-key update, and there was no effect (two keys unchanged). The output of apt-get update and apt-get upgrade, and the contents of /etc/apt/sources.list, can be found in .


After drawing a segmented circle in Adobe Illustrator using the Polar Grid Tool, how do you make each of the segments into individual layers that arent connected to the whole circle?

Is there a fairly simple way to divide a circle into equal parts using Adobe Illustrator CC?


My husband is travelling back to SA in 3 weeks.  He is a dual citizen AUS/SA. His SA passport is expired. What should he do when crossing immigration controls in South Africa?    Enter on AUS passport and hope they dont notice his place of birth 'Cape Town'   or   Enter on expired SA passport and just tell them he made a mistake by not checking it early enough to renew for this trip?

What will happen if I arrive at the border with my expired South African passport?    I can leave Australia on my current Australian passport so boarding the plane is not an issue, and South Africa can't prevent me from entering (I believe) as I was born there, but    will there be a fine? Will there be any issue?    I have my birth certificate and ID document, but am unable to replace my passport in time.


I will be using ubuntu for a research experiment at a university. I will be needing to put all meterials on a open science framework website, and am wondering if its legal to post a system image that was used to run it?

I have a website with adsense. Can I share Linux distro VirtualBox images with users? Is this legal? Will it affect my adsense account?


I get a string in PHP and I need to look up the values of the IDs, can be 1, how can be 100 IDs, how to do? I tried something like this:  $text = 'Name1 John Name2 Mike'; preg_match_all('/ Array ( [0] => John Name2 Array ( [0] => b">John Name2

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


I am trying to get the inverse of: $$g(x) = \int _a ^x h(t) dt$$ That is, I want to find a general expression for $g^{-1}(x)$ and was wondering whether there are theorems I can apply. Thanks

The function $g$ is strictly positive. Let the function $f$ be defined as   $$f(x) = \int_0^x g(u) du$$  Is there a way to express $f^{-1}(x)$ in terms of $g$?


I am trying to update my Macbook Air 13'' 2017. When I first tried it, it failed. When I tried it again, the progress bar would quickly progress to 713 MB, wait there for a while. Then it continues to download, goes till 5.5 GB, and then it fails again. This is the message I get.  I have tried the following:  Deleted the folders in /Library/Updates/ Deleted the files in /private/var/folders/zz/<hash>/C/com.apple.SoftwareUpdate  Each time, it still fails

I am currently using a MacBook Pro 13" Mid 2018 with Touch Bar. Today macOS Big Sur was released and I tried to download it but it's getting stuck at 484.4 MB. Initially, it shows 16-17 minutes left, but as soon as it reaches 484.4 MB it's stuck and the timer goes till 10 hours! My Wi-Fi is totally stable with a speed of 100 Mbps. I tried to restart my Mac but it still gets stuck. Earlier there were similar issues in the App Store (even now they are). The issue was I was not able to download an app unless I connect to the US VPN. I even contacted support but they were not able to help out. It wasn't a big deal as a VPN could be used. But now even with VPN, it gets stuck.


I'm trying to use regexp in javascript to match a group of patterns but for some reason when I'm trying to console.log the group, it's just logging out characters instead of the entire pattern. What I am doing wrong? Also, the g flag is required for this pattern.  var string = "group1group2group3 group4group4group4 group1group2group3"; var matches = string.match(new RegExp("(group1)(group2)(group3)", "g"));  console.log(matches[0][0]+matches[0][1]+matches[0][2]);    Result:    gro   Expected Result:   group1group2group3

I want to match a portion of a string using a  and then access that parenthesized substring:  var myString = "something format_abc"; // I want "abc"  var arr = /(?:^|\s)format_(.*?)(?:\s|$)/.exec(myString);  console.log(arr);     // Prints: [" format_abc", "abc"] .. so far so good. console.log(arr[1]);  // Prints: undefined  (???) console.log(arr[0]);  // Prints: format_undefined (!!!)   What am I doing wrong?    I've discovered that there was nothing wrong with the regular expression code above: the actual string which I was testing against was this:  "date format_%A"   Reporting that "%A" is undefined seems a very strange behaviour, but it is not directly related to this question, so I've opened a new one, .    The issue was that console.log takes its parameters like a printf statement, and since the string I was logging ("%A") had a special value, it was trying to find the value of the next parameter.


I am using JavaFX and this is my code. I am trying to make a column of five labels, textfields and hBoxes.       Label[] lblTask = new Label[5];     TextField[] taskTF = new TextField[5];     HBox[] hb = new HBox[5];      for(int i = 0; i < 5; i++) {         hb[i].getChildren().addAll(lblTask[i],taskTF[i]);         hb[i].setSpacing(10);         hb[i].setLayoutX(30);         hb[i].setLayoutY(120+(60*i));         root.getChildren().add(hb[i]);     }   It is giving me a java.lang.reflect.InvocationTargetException, and java.lang.RuntimeException and a java.lang.NullPointerException on the line that I set the spacing!

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


What is the sum of number of ways of choosing $n$ elements from $(n+r)$ elements where $r$ is fixed and $n$ varies from $1$ to $m$ ? Can this be reduced to a formula ?  $$ \sum ^m _{n=1} \binom{n + r}n $$

Let $n$ be a nonnegative integer, and $k$ a positive integer. Could someone explain to me why the identity $$ \sum_{i=0}^n\binom{i+k-1}{k-1}=\binom{n+k}{k} $$ holds?


What android phones and tablets are compatible with Ubuntu?

With the announcement of the Ubuntu Phone OS I'd like to know what phone (and tablet) models are supported at this time.  Note from foss & Oli: We are making this the master question for all future "Will this work on <insert random tablet/phone/device here>?!" questions


I am currently considering installing Ubuntu Server 18.04 LTS on a new box that will be very I/O intensive (multiple Samsung 970 Pros used for a crap-ton of random R/W I/O), instead of the usual CentOs (with its ancient 3.x series stock Linux Kernel). I was wondering what stock kernel Ubuntu Server 18.04 LTS will be packaged with?  I know that Ubuntu 18.04 LTS itself has a pretty recent kernel and am wondering what the Ubuntu team chose for the Server release.

Is there a list of Ubuntu versions with default corresponding Linux kernel versions somewhere?  I would specifically like to know the most recent version of Ubuntu that still used Linux Kernel 2.x.


I've just integrating my POP3 email for my business into a Gmail account. I like using Chrome's application shortcuts to open Gmail and Google Reader.  Thing is, I also have a personal Gmail address that I often check "at work", and my Reader subscriptions are also in my personal account.  Problem is, Chrome will only keep me logged in to one account at a time.I don't want to keep logging out of one and into another account.  Can I set one shortcut to open one account, and another to use a different account?

I am specifying a custom user agent in Google Chrome in order to access a legacy web site on my company's intranet (the site is needlessly requiring IE). I created an application shortcut for the site and added the --user-agent parameter to the shortcut.  If I launch this shortcut without Chrome already running, things work fine. However, if I launch the application shortcut when another Chrome window is already open, the --user-agent parameter is ignored and the normal user-agent is used.  So, it appears that whatever user agent string is used when the first Chrome window is opened is what will be used for all future windows or application shortcuts. Is there any way to get around this behavior?


Saw this in the late eighties. Boy escapes the grasp of an all female command and having been misled to believe a holocaust type scenario joins with a girl.  They work their way through a series of rooms. The final scene, I remember, involves the boy slicing the wall with a knife to reveal sunlight and sand (beach or desert).  It was a false lie in a totalitarian underground cult. I believe it was subtitled thus foreign.

My recollection is very sketchy but this is what I remember....   Film was possibly black and white I saw it as a child in the late '80s early '90s but it's older It was subtitled and in Russian or similar language It involved some astronauts  travelling in space with possibly time travel The astronauts (mostly men) encounter a planet/civilization of only women The women no longer need men to breed and are so become superior and possibly want to eliminate all men    That's all I have to go on, sorry.


I am currently a PhD student and I need to choose a dissertation committee as I will be graduating soon. (I already have a postdoc lined up.) It seems the only function of this committee is to read my thesis, attend my defense, and decide whether to grant me a PhD.   Assuming my dissertation committee serves its purpose and grants me a PhD, what further relevance do they have? How should I choose my committee? In particular, is my committee still important after I graduate?  The reason I'm asking is because I don't really know who to choose. It seems like I should just ask whoever in my department is available. Should I be considering other factors? For example, it is good to have "famous" researchers on my committee?  I asked my advisor and she didn't voice an opinion and said it was essentially up to me who to choose.

I'm currently developing my dissertation proposal, and am in the process of choosing my committee members.  I have heard that one should carefully choose their committee members, since they ultimately judge if and when your PhD work is done.  As far as I can tell, a committee member should at least have some expertise in my research topic.  I'm sure there's more to it than that, but I want to know what other qualities should I look out for?  What qualities in a committee member should I avoid?  I imagine these other qualities are subtle and difficult to judge at first.  Nonetheless, how do I know if they are a good fit for the success of my PhD?


I have more older versions of NetBeans installed on my system and I would like to uninstall them.  The problem is that I have installed them all from a .sh shell installer script simply running from cmd and none of Synaptics, apt, dpkg nor Software center knows about any NetBeans installation.  I know I could probably run the installer again and select the Uninstall/Remove option but I have already deleted all of the installers long time ago and downloading them again just to be able to uninstall current installations is not a solution for me.  Is it possible to just delete the local files (since none of the packaging software knows about them) and consider this operation as uninstall? Or is there some better option?

Since I did not install NetBeans via the Software Center (I installed it as an .sh file) I can't see an easy way of uninstalling the program.  How can I safely uninstall the program?


After I've used .insertBefore to place div the page, the div doesn't appear to be recognized as jQuery("#temp").  Is there something special I need to do to get it to be active and receive onClick actions?  jQuery( document ).ready(function() {      var temp_text = '
temp
';      if ( jQuery.temp("temp") )         console.log( 'FOUND temp' );     else         jQuery( temp_text ).insertBefore( "#top-bar" );  });  jQuery("#temp").on("click", function () {     console.log('clicked'); });

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.


If a feat or power gives you two attacks, is that two attacks per BAB, or is is two attacks total?  Here is the power that prompted this question:

Okay, I need some clarification. The  state this about natural attacks:     You do not receive additional natural attacks for a high base attack bonus. Instead, you receive additional attack rolls for multiple limb and body parts capable of making the attack (as noted by the race or ability that grants the attacks).   Let's say that I can shape into an . My BAB is +8/+3 and STR 5. An Oliphant has two natural attacks: Gore and Stomp (x2).  Reading the rules, it seems that I can't do two Gore attacks, like:   1st attack: AB +13. DAM 2d8 + 5 2nd attack: AB +8. DAM 2d8 + 5   because I don't get additional attacks for a high BAB. Does that mean I need to combine attacks instead? Example:   (Gore) 1st attack, AB +13. DAM 2d8 + 5 (2 Stomps) 2nd attack, AB +6*. DAM 2d6 + 5 * With the Multiattack feat, reduces secondary weapon penalty to −2.   Also, does the damage from the two stomps equal 2d6 + 5, or should I roll damage for each stomp? (1st foot = 2d6 + 5, 2nd foot = 2d6 + 5).


Given two confidence bands, it seems natural to consider the confidence band of the product of these two distributions. Does this have a name? Are there any reference that might be helpful regarding this notion?  Edit: Assume that the errors of the first, say, regression curve are not correlated with the errors of the second.

Let us assume we have two parameters, $p_1$ and $p_2$. We also have two maximum likelihood estimators $\hat{p_1}$ and $\hat{p_2}$ and two confidence intervals for these parameters. Is there a way to build a confidence interval for $p_1p_2$?


How can I prevent Windows 8 from trying to format my external ext3-format hard disk?  Every time I connect my ext3-format hard disk for the guest virtual machine(ubuntu), Windows(host) shows the dialog that it is about to format my ext3-format disk.  ubuntu(guest) - virtual box - windows(host) - ext-format external disk  I'm afraid I may push the confirm button accidentally someday.  I do not want to see the dialog to format it.  Anyway, I'm using Windows 8.    EDIT:   I changed Windows into Windows 8 Sorry, everyone. I forgot to mention I'm using ext-format external disk for the virtual box guest machine. I forgot it since I had intended to ask this question inside .

I've started using TrueCrypt to encrypt a partition on an external USB hard drive. I've opted for using a raw partition as opposed to a file container.  But here's the annoyance. Whenever I connect this drive to a computer running Vista or Windows 7, I get the message popup "You need to format the disk in drive J: before you can use it".   The default option is "Format disk", and I'm afraid one of these days I'll accidentally trigger it.  Is there any way to disable this message?


A friend of mine found an old Windows7 disk but is unable to determine the point mentioned in the title. I have checked the autorun.ini file, the contents of which is this:  [AutoRun.Amd64] open=setup.exe icon=setup.exe,0  [AutoRun] open=sources\sperr32.exe x64 icon=sources\sperr32.exe,0   How can I determine what version this Windows disk is?

I've got a DVD that I've burnt from an MSDN ISO. I'm not entirely sure if its Windows 7 64bit or 32bit.   How can I be sure?


Can the 700 x 38c tire on the Trek DS2 be used on the Trek Verve 3 which comes with a 700 x 45?

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


I am creating a custom DML Log in our Salesforce sandbox, and I created a Class & method that fires based on an Apex Trigger Here's the class:  public class Util {  public static void logDmlDeleted(Sobject[] sObjList) {     DML_Log__c[] logInsList = new List<DML_Log__c>();     for (Sobject sobj : sobjList)        logInsList.add(new DML_Log__c(SObject_Type__c = sobj.getSobjectType().getDescribe().getName(),                                                 Name__c = (String) sobj.get('name'),                                  SObject_Id__c = (String) sobj.get('Id')                                  ));      insert logInsList;      } }   The SObject_Id__c was an addition I added to record the Id of the sObject. It looks like this is working, except for the fact that there is an additional string of characters randomly appended: 'MAU'.   Here's a standalone sObject String Id:     a0HJ0000007yBdQ   And here is how that Id is written to the DML Log field:     a0HJ0000007yBdQMAU   How can I adjust the statement in the method so only the string's virgin Id is passed into the field?

I have a trigger where i am assigning ID to a cusotm field like below -   D.customfield__c = acc.Id;   The ID is coming as 00P28000000EwpjEA0  But i need only 00P28000000Ewpj 15 char. Is there is a way to use substring in apex trigger. I can't use formula field.


In a 2D plot (with x and y), what's the correct name of the diagonal lines, i.e. the line at 45° and that at 135°?

Hello.  I'm looking for the English name of these two lines in a two dimensional plane:   they go through the origin they make angles of 45° and 135° with the $x$-axis, dividing the plane in two parts    From my native language, they would translate to "first bissector" and "second bissector" or "first diagonal" and "second diagonal", but I could not find any reference to such names.


I have studied from Griffiths, the relativistic form of momentum is $$p = \frac{1}{\sqrt{1-\frac{v^2}{c^2}}} m_0v$$   Now when I evaluate the momentum for photon, I just insert $v=c$ and $m_0=0$ and I get $p= 0/0$. How does it make sense?   Can you tell me that where I am wrong?

As an explanation of why a large gravitational field (such as a black hole) can bend light, I have heard that light has momentum. This is given as a solution to the problem of only massive objects being affected by gravity. However, momentum is the product of mass and velocity, so, by this definition, massless photons cannot have momentum.  How can photons have momentum?   How is this momentum defined (equations)?


I know the definition of prime in $\mathbb{Q}(\sqrt{m})$ that is an algebraic integer is a prime if it is divisible by its associates and units of the field. Units of $\mathbb{Q}(i)$ are $+1,-1,i,-i$  How to solve this example?please help me.

Is it true that $a+bi$ is prime in $\mathbb{Z}[i]$ if and only if $a^2+b^2$ is prime in $\mathbb{Z}$?    How can I prove this? Can anybody help me please?


Recently I have found a great PHD position which on some aspect exactly fit with my CV.  I am looking for the best email type to introduce my self to the professor? what information are necessary on my email.   Do you show me any examples or links?

When needing to ask a professor about something important and potentially delicate, what is an appropriate way to phrase the question or write the email?  Examples include:   Requesting a recommendation letter Asking for exceptions to policy (e.g., ignoring a course prerequisite, rescheduling an exam) Asking if you can do research with them, join a group, get into a program Scheduling a meeting, exam, or defense Letting them know about a change of plans Letting them know about a life event affecting your work or studies (e.g., wedding, funeral, sickness, vacation)


Let $X=\{p,q,r,s\}$ with  topology induced by basis $\{p\}$,$\{r\}$,$\{p,q,r\}$, $\{p,r,s\}$. Then $X$ is not simply connected.   My Attempt:  $\{p\}$ is open set and $\{q\}$ is closed set.  Define $\phi:[0,1]\to X$, where  $$\phi(x)=\begin{cases} q & x=0,1,\\ p & x\in (0,1). \end{cases}.$$  $\phi$ is a continuous loop. But how to show it is not homotopic to constant?  Any Help will be appreciated.

Let $S$ be de pseudo circle (see for instance ).  How can I compute its higher homotopy groups?  The question came up while trying construct a weak homotopy equivalence $X\to Y$ that does not admit an inverse. Taking $X=S^1$, $Y=S$ and $f$ as in the wikipedia page should work, but I was not able to work out a "simple" way of calculating $\pi_n(S)$ for $n>1$. By "simple" I mean that it should not invoke a generalization of that I am trying to prove.


Suppose I have perfect planar fragments of a big image. How to stitch them automatically?  Software should detect edge features but should not expect camera calibration.

I can create a collection of pictures giving a 360-degree view from a certain spot, just taking a bunch of photographs from the same spot but in a different direction.  However, what software could I use (on Windows) to stitch these images together to get one big image?  I prefer something that would stitch them together without showing any seams.


Can someone explain this to me? I have one pokemon placed at a gymn and I collected the 10 pokecoins immediately.  When I placed another pokemon at another gym, I was not able to collect any pokecoins because it has not been 21 hours yet.  However, my two pokemons were defeated shortly after I placed them at the gyms.    Does that mean, in order to collect for the 2nd pokemon, I must be able to hang in that gym for more than 21 hours?  So I tried a second strategy - placed the pokemon first and then collect later, hoping that within 21 hours I can place several pokemons at different gyms.  No such luck. My first one was again defeated within hours and I never got to collect anything.  So how do you collect defend bonus for more than one pokemon at a time?  Thanks.

When one places one or more Pokémon in Gyms, a "Defender Bonus" becomes available via a shield in the upper right corner in the shop screen. The couple of times that I've put Pokémon into gyms, I have later on clicked on the shield and received some items (quantities of stardust and gold, if I recall correctly), and the shield then shows a countdown timer until the next bonus is available (I believe - haven't actually had any Pokémons in Gyms long enough to find out). The bonus doesn't just automatically happen, one needs to trigger it by clicking on the shield.  Does anyone know of some especially good strategy for when to claim the rewards? Is it better to wait until many Pokémons are assigned to different gyms? Does taking the bonus after placing your first one keep you from accruing bonuses for subsequent Pokémons placed in gyms until the original timer runs out? Does the amount of bonus vary depending on when you claim it, or is it fixed for the number of Pokémon one currently has in Gyms? (Or somewhat random, but not influenced by timing?) Is there any association to calendar days, or is it strictly a countdown timer? (i.e. If the time is currently close to midnight, is there any particular reason to hurry to accept the bonus before, or to delay until after, midnight?). Thanks!


how can I move a file to trash using an alias?

I would like to know if there is a command I can issue in a terminal so I do not classically remove (rm) the file, but instead move it to trash (i.e. Nautilus Move to Trash behavior).  In case there is such a command, I would also be interested in knowing what it is.


Let's define free will as the ability for a human being to make a choice that does not completely depend on the history of the universe. The universe may be assumed to be indeterministic. Any simple choice will do: am I going to order a Coke or a Sprite?  Has anyone described what the universe must be like in order for this kind of free will to be able to exist? A universe where an agent making the choice exerts causal influence on the universe? In what kind of universe would this be possible, while not running afoul of dualism?   [1]

Why is free will a widely discussed, established concept? Does this concept emerge from religious / spiritual doctrine? Why is there so much interest in this topic?  If a neural-network based AI machine with a certain high degree of complexity scores a perfect 100 every run in a turing test, have we not already refuted the idea of free will? In fact, let me extend this reasoning, if ANY machine scores a single point in a turing test (and not 100), have we not already disproved (or alternatively put in great doubt the existence of) free will? If we already created a machine that can master a certain degree of human interaction, have we not then demonstrated that human interaction is programmable? (given enough time for the creation of a complex or more appropriately elaborative neural system).   From the perspective of an external observer, such a machine would be qualitatively human although intrinsically quantitative behind a stream of 1's and 0's. It would exhibit a type of decision making indistinguishable from that of a human. Does this not reduce the type of decision making we understand to be "free will" to something quantitative, deterministic, materialist?


//main code  public static void main(String[] args) {  //initiate game board  initGame();     //start the game     do {         PlayerMove(Cplayer);         updategame(Cplayer, crow, ccol);         printboard();         //game over message         if (currentstate == you_win){             System.out.println("'X' Won!!");             else if (currentstate == comp_win)                 System.out.println("'O' won!!");                 else if (currentstate == draw)                 System.out.println("It's a Draw :(");         }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I have been thinking about this problem:  Suppose we have all $R$ by $C$ matrices, where the values are integers in $[1,n]$. Two matrices are equivalent under interchanging rows and columns. For example,   1 5     0 0       would be equal to itself and to  0 0 1 5   and would be equal to  0 0  5 1   and would be equal to   5 1 0 0   How many unique such matrices are there?  Any ideas how to go about it? Any help much appreciated!

If I have a $w \times h$ matrix where each value is an integer  $0 \lt n \lt 20$,  how can I count the number of distinct configurations, where $2$ configurations are "distinct" if there is no way to reshuffle the rows and columns that would produce the same matrix?  Can this be counted with the stars and bars method?    For example, these are equal (we swapped a row, then a column):  0 0 0    2 0 4 0 2 4    0 0 0   but these are distinct (no way to swap rows or columns to produce the other):  0 0 0    2 0 0 0 2 4    0 4 0   It seems like there ought to be a way to count the rows or columns as "bins" and the values as balls.  I realize that in this case there are $18$ different colored balls, but even if the only values possible were $1$ and $0$, (ball or no ball) I can't see how to represent it as stars and bars.


I have the following problem.   I have to find the limit of $b_n = \frac{a_n}{n}$, where $\lim\limits_{n\to\infty}(a_{n+1}-a_n)=l$  My approach:  I express $a_n$ in terms of $b_n$, i.e. $a_n=nb_n$ and $a_{n+1}=(n+1)b_n$  We look at the difference: $a_{n+1}-a_n=(n+1)b_{n+1}-nb_n$  Assuming that $b_n$ converges to a real number m, we see that:  $l=(n+1)m-nm$, from where I conclude that $m=l$.  What I'm left with is proving that $b_n$ is convergent which I'm not sure how to do.  Thanks in advance!

If $\{x_n\}$ is a sequence which satisfies $\lim_{n \rightarrow\infty} ~ x_{n+1} - x_n= c$  where $c$ is a real positive number. Then what can be said about the convergence/ divergence, boundedness/ unboundedness of $\{x_n/n\}$.  Attempt: $\lim_{n \rightarrow\infty} ~ x_{n+1} - x_n= c$ where $c >0$  => $x_n$ is unbounded and divergent.  However, I am stuck on how to relate this to convergence/divergence of $x_n/n$ . Thanks for the help.


I have a basic UI panel with a basic dropdown and I want the user to be able to select a collection from the list and have it passed back to the code. I know how to access the list of all collections: list(bpy.data.collections), and I can use a loop to get each collection by name. I can't figure out how to update the enum items with these collections, though. How do you update a enum with items from a list? It's just a basic, templated, enum:     my_enum: EnumProperty(         name="Collection",         description="Apply Data to attribute.",         items=[ ('OP1', "Option 1", ""),                 ('OP2', "Option 2", ""),                 ('OP3', "Option 3", ""),                ]         )

I'm writting an addon with an UI. In my draw function in my UI class I've this   layout.prop(bpy.context.scene, 'activebone', text='active bone')   Wich create an enum in the UI.    And in my register class I've this:  bpy.types.Scene.activebone = bpy.props.EnumProperty(items=active_bone)   In my draw fonction I fill the active_bone list with the some data and but the enum don't refresh himself. I know that i can retype  bpy.types.Scene.activebone = bpy.props.EnumProperty(items=active_bone)   But the draw function is Read only so I can't. Is it possible to refresh my Enum item in the draw function or am I obliged to do it in an other class like a button?


Here is my passage:     Everybody else in our party [has/have] missions of their own.   Now, Everybody else in our party has a mission of their own sounds pretty straightforward. But as soon as I make mission plural, it doesn't sound right. Yet plurality should reflect Everybody else, shouldn't it?

Which is correct?     Everyone were convinced that he would go to the game.   Everyone was convinced that he would go to the game.   I think it's "was", because "everyone" is singular, but I just wanted to check.


I have noticed that it seems to be good etiquette to write the "at" sign and then the userid of the person whose post or comment one is responding to in a comment.  I believe that's called pinging.  I've tried to do this and sometimes it works, and sometimes it just disappears when I hit "Enter."  Am I supposed to ping?  If so, are there some tricks to make it work more consistently?  Or could someone at least explain the pattern to me?

How do the comment replies (aka "pinging users") work?  Who can I send an @reply to? How do I respond to a specific user when entering my comment? Will they be notified? What do people mean when they talk about "pinging" another user?  Related:


I read this trilogy in the 90's, though it might be older. There is a felinoid security officer on the starship who goes EVA from one hatch to another in an effort to prove that it was possible for an opposing infiltrator/saboteur/assassin to do so.  The very much disliked hard horse captain of the ship has a partial brain augmentation (I believe to repair damage). I don't remember how, but the opposing force managed to place get him into a chamber filled with the gas used in suspended animation without the prerequisite drugging and preparation leaving the crew wondering if the man was actually dead or if his implant had absorbed enough of his personality to make it appear as though he were still alive.

Plot Details/Summary  I remember this one as being an entertaining, if somewhat run-of-the-mill, "galactic war" type story.  The story takes place aboard a Terran military starship (a destroyer by definition, IIRC) assigned to patrol and defense duties of a human-colonized star system.  Many of the supporting themes and plot devices were common sci-fi tropes, almost to the point of cliché.  The ship is an old, obsolescent vessel guarding a backwater system no one particularly cares about at HQ.  Nothing really ever happens here, but the fleet has to send something out to protect them, so they send this lone, aging vessel.  I remember a line about the ship smelling of old plastic or something like that. It's generally understood that if there was a serious incursion by whatever alien race Man is at war with, the ship probably wouldn't be up to the task.  Likewise, the crew isn't exactly top notch, either.  They are demoralized, with personality conflicts and egos clashing frequently.  I recall a scene where an officer aboard the ship, in an attempt to dominate, or possibly "send a message" to an troublesome junior officer, beats the other man in the showers.  I recall a line about the senior officer reversing the ions in the climate controls in the room in order to agitate the situation, and something about kicking the other man in the stomach with his bare foot.  What is a bit unusual about the story is the weaponry they use in combat.  The ship has an array of energy weapons - there is a line about banks of lasers, masers, and phasers (it's not a Trek novel).  But the only weapon they actually use in combat against enemy vessels are the FTL-capable missiles I mentioned in the title.  FTL travel is possible in this universe by the creation of a warp "bubble" that surrounds a starship.  This energy bubble allows for tremendous speeds - I think the human ship can travel up to 180 times the speed of light with their FTL drives.  The alien vessels also use this method of FTL travel.   The danger with this "bubble" is that if one warp bubble intersects another warp bubble, there is a tremendous release of destructive energy.  Thus, the primary weapon for fighting a starship is a FTL missile that generates its own warp bubble.  If you can intersect the enemy vessel's bubble with a missile's bubble, it's game over, so to speak.  The only real defense is to intercept the enemy's missiles with your own FTL missiles.  At some point, an alien vessel does come to the backwater system, and suddenly the crew of the old starship have a serious challenge before them.   I am very fuzzy on how the conflict plays out.  I believe there are several engagements prior to the final one.  It may play out a bit like the old WW2 movie The Enemy Below or the derivative TOS Trek episode "Balance of Terror."  Except that I don't think we ever get the alien perspective in this story.  The climax of the novel comes with the final battle between the Terran ship and the alien one.  Salvos of missiles are fired, with several tense moments.  Eventually, the humans manage to get one of their missiles through and hit the alien's warp field.   The alien ship is utterly destroyed and the Terran crew are buoyed by their victory.  Hard feelings and defeat are forgotten in this moment of triumph.  Something like that.  Timeframe of Publication  I'd guess the novel came out in the 1970s or 1980s.  Probably not any later than that.


How to change or update array value in PHP through array number?  Example:  $array1 = array("cat","dog","mouse","dog");   I want to change the value of dog in the 2nd array only

Is there an easy way to delete an element from an array using PHP, such that foreach ($array) no longer includes that element?  I thought that setting it to null would do it, but apparently it does not work.


I am trying to find the path of basic commands like ls or cd using which command. I see the path for ls but not for cd. Of course both the commands work fine. Any idea?  $ which ls /bin/ls $ which cd $

I've always wondered why cd isn't a program, but never managed to find the answer.  Anyone know why this is the case?