Suppose $f:[0,\infty]\rightarrow$ to R and has continuous $f'(x)$ and $f''(x)$ f(x) → 0 as x → ∞. Show that f′(x)→0 as x→∞

Suppose $f:[0,\infty)$ $\rightarrow$ R and has continuous $f'(x)$ and $f''(x) $ .  $f(x) $$\rightarrow $0 as $x$ $\rightarrow$ $\infty$. Given $f'(x)\rightarrow b$ as $x \rightarrow \infty$  show that $b=0$  Get stuck in the first place, but I tried to use Mean Value Theorem and then connected it to the limits.  Any hint?


I have a kinda deep C experience but I am a C++ beginner. References seem to be easier to use than pointers, but it drives me crazy. I think all references can be replaced with pointers. In my case, pointers are not that hard because I spent tons of times studying them. Is it common among C++ programmers to use references or is it just recommended??


Can open-circuit voltage be treated as voltage to find power dissipated? I combined all the resistors (including Vlamp) to get one resistor of 40/6 Ohms (Correct me if I'm wrong). Using Ohm's law to find the current doesn't work since I don't know the voltage, Thus the title. I don't think so but I wasn't taught this in detail and Googling doesn't benefit since Wikipedia has a page  I already figured out that: Battery has open circuit voltage of 4V R1 = 5 Ohms R2 = 5 Ohms k = 0.2A/V When lamp on and Vlamp = 2V, Rbat = 10 Ohms   The lamp turns on if the voltage across the lamp is greater than 2V. When the lamp is on it has an internal resistance of 10 Ohms, and when it is off it acts like an open circuit.   This is what I calculated:    I'm getting Ilamp as 1/5, still trying to see how that will help... EDIT: My answer has been suggested as a duplicate. Is it the same question? NO. Is it the same answer? NO.    The only thing that is the same is the circuit, any objections?


I am working with a dataset (900 observations) and have the following normal QQ plot in R:    Seeing that the QQ-plot little bit strange, what could I infer about the underlying distribution? It seems to me that a distribution has too many pikes at 2, is that right? Also, what other conclusions can we draw from the data?


A friend of mine has a Notebook with two hard disks, one SSD and one HDD. The SSD held a Windows 7 installation, the HDD contained most of his data. After a bluescreen, the computer won't boot anymore. I've already re-written the MBR (BIOS-based system) using bootrec \fixboot on Windows 7 installation DVD, but to no avail.  Furthermore, when trying cd /D C:\ (the SSD) from the command line on the installation DVD, the execution failed stating an I/O error. cd /D D:\ (the HDD) works fine. Since the system is only a few months old, I hope that only the file system crashed on the SSD, and not the SSD itself. I want to try data recovery on the SSD that doesn't boot anymore, what's the best way to accomplish this? Are there any open source- / freeware-tools you can recommend?


Proof that set $\{0, 1\}^{*}$ of all bit strings are countable?

I can't seem to solve this question, I found similar questions, but I wouldn't consider them exactly the same. Struggle to understand what the asterix means in this situation?


What is $\lim_{x \rightarrow 0} x\log(x)$?

Is it true that:  $$\lim_{x \rightarrow 0} x\log_{n}(x) = 0 \quad ; \quad n \in \mathbb{R}$$


How do I export an XNA crossplateform project to Nintendo 3ds or Nintendo Switch?

I would like to document my self a bit about 3ds and switch game creation. I know that modern game engine have builtin tools to export games to these platforms, but I could not find - in google research - an article or a website talking about this. Any time I searched "Xna Export to nintendo 3ds" I ended up with "getting 3ds max files into an XNA game" stuff. I'll be highly grateful to anyone that could help me find a way to export my games to these,


How do I prove ~(A & B) therefore ~A V ~B using natural deduction?

Been trying to prove this one for a while now and can't crack it.   Assume ¬(A ∧ B) Derive ¬A ∨ ¬B


I did it... I guess everyone does it sometime, but this was my first. I executed sudo chown -R /usr/bin and before I realized my mistake, it was too late... Now I can't access sudo because I receive the following error: sudo: must be setuid root. I would really appreciate if I could avoid a complete reinstall of ubuntu because that would require far too much work :(  Here is the commands I've tried without success (in recovery mode):  chown root:root /usr/bin/sudo chmod 4755 /usr/bin/sudo   I've also tried chmod 0440 /etc/sudoers all without success. Any ideas about what I can try to fix it?  NOTE: Sorry for creating another one of these threads, but since I knew the exact command I executed to blow it all up, I thought that might make a difference :)


How to find the eigenvalues of tridiagonal Toeplitz matrix?

Assume the tridiagonal matrix $T$ is in this form:  $$ T = \begin{bmatrix} a       & c        &              &              &   &\\ b       & a        & c            &              &   &\\         & b        & a            & c            &   &\\         &          &              &\ddots        &   &\\         &          &              & b            & a & c\\         &          &              &              & b & a\\ \end{bmatrix} $$  we must show that its eigenvalues are of the form   $$a + 2 \sqrt{bc} \, \cos \left( \frac{k \pi}{n+1} \right)$$  where $$a=qh^2−1, ~~ b=1- \frac{ph}{2}, ~~ c =1+\frac{ph}{2} , ~~q \leq 0.$$


Lebesgue Measure of the Graph of a Function

Let $f:R^n \rightarrow R^m$ be any function. Will the graph of $f$ always have Lebesgue measure zero?  $(1)$ I could prove that this is true if $f$ is continuous.  $(2)$ I suspect it is true if $f$ is measurable, but I'm not sure. (My idea was to use Fubini's Theorem to integrate the indicator function of the graph, but I don't know if I'm using the Theorem properly).  If $(2)$ is incorrect, what would be a counterexample where the graph of $f$ has positive measure?  If $(2)$ is correct, can we prove the existence of a non-measurable function whose graph has positive outer measure?


How can you prove that $\sum\limits_k \frac1{p_k}$, where $p_k$ is the $k$-th prime, does not result in an integer?


$\frac{1}{z}-\frac{1}{\sin z}$ at the origin - Classify singularities

I tried for a while to classifiy the singularities of $\frac{1}{z}-\frac{1}{\sin z}$ at the origin, but I am stucked. Is there someone who is able to help me at this point?


So I'm coming over from Java, and I've been seeing (and using), a ton of these:  ["foo bar"] void method(param params) {      ..code things }   Can someone explain to me what they are? I don't even know what they're called, so I can't manage to figure it out from documentation.


I am trying to write a dieresis with TexWorks (version 0.4.5 with Windows 8.1, if needed) with the code:  \"{a}   it should be correct, but this is what I get:


A is a $n\times k $ matrix.  I have to show that $\|A\|_2\leq \sqrt{\|A\|_1\cdot \|A\|_\infty}$.   I know that $\|A\|_2^2 = \rho(A^H\cdot A)\leq \|A^H \cdot A\| $ for every $\| \cdot  \|$ submultiplicative matrix norm, but I don't know how to conclude.  Any idea?


On a linux  networked machine,  i would like to restrict the set of addresses on the "public" zone  (firewalld concept), that are allowed to reach it. So the end result would be no other machine can access  any port or protocol, except those explicitly allowed, sort of a mix of     --add-rich-rule='rule family="ipv4" source not  address="192.168.56.120" drop'    --add-rich-rule='rule family="ipv4" source not  address="192.168.56.105" drop'   The problem above is that  this is not a real list, it will block everything since if its one address its blocked by not being the same as the other, generating an accidental "drop all" effect,  how would i  "unblock" a specific non contiguous set? does source accept a list of addresses? i have not see anything in my look at the docs or google result so far.     EDIT: I  just  created this:  # firewall-cmd  --zone=encrypt --list-all encrypt (active)   interfaces: eth1   sources: 192.168.56.120   services: ssh   ports: 6000/tcp   masquerade: no   forward-ports:    icmp-blocks:    rich rules:    But i can still reach port 6000 from  .123   my intention was that   if a source is not listed, it should not be able to reach any service or port


Kernel of an evaluation homomorphism $\mathbb{C}[X_1,\dots, X_n] \rightarrow \mathbb{C}$

Let $R:=\mathbb{C}[X_1,\dots, X_n]$, $a=(a_1,\dots, a_n)\in \mathbb{C}^n$ and $\phi_a:R\rightarrow \mathbb{C}$, $\phi_a(f)=f(a)$. I want to show that $\ker(\phi_a)=(X_1-a_1,\dots, X_n -a_n)$.    I know that to be true for $n=1$ and I also know that $\ker(\phi_a)$  is a maximal ideal in $R$. Moreover, $(X_1-a_1,\dots, X_n -a_n) \subseteq \ker(\phi_a)$ is obvious.  I am note sure if I can do an induction in this case.  Thank you.


When can and can't method calls change a parameter in Java?

This is in java. I tried looking for / googling for an answer to this question here and couldn't find a sufficient answer, so I apologize if this is a duplicate. I am confused as to the rules behind methods changing the parameter that you input. For example, consider the following example  public static void messWithArray(int[] array) {      array[0] = 100;      array[0] += 5;       // make new array      int[] array2 = new int[10];      for(int i = 0; i < 10; i++)      {          array2[i] = 5+i;      }      array = array2  }  public static void main(String[] args)  {      int[] a = new int[10]      for(int i=0; i < 10; i++)      {          a[i] = i*10      }      messWithArray(a);      System.out.println(a[0]);      System.out.println(a[1]);   This prints that a[0] is 105 and a[1] is 10, so making array[0] equal to 100 and adding 5 to it in the messWithArray method had an effect. However, assigning array = array2 didn't do anything (since a[1] is 10). I also tried messing with an int but couldn't get it to work.  I would like to know more specifically/clearly the logic behind whether or not a method will change attributes of an array.


How do I programmatically change the color of a CEdit?

I'm writing a dialog using MFC in C++. The dialog has various CEdit fields and a function that validates all fields. If any field is filled with invalid data, this function disables the OK button. However I would like this function to also indicate which field is invalid. Currently, the function looks like this:  bool myDlg::validateAll() {     bool bReturnVal = true;     CBrush red_brush;     COLORREF red = RGB(255, 204, 204);     red_brush.CreateSolidBrush(red);     CDC* pDC;      if (!myCEditIsValid())) {         bReturnVal = false;         pDC = GetDlgItem(MY_CEDIT_ID)->GetDC();         pDC->SetBkColor(red);     }     if (!myOtherCEditIsValid()) {         bReturnVal = false;         pDC = GetDlgItem(MY_OTHER_CEDIT_ID)->GetDC();         pDC->SetBkColor(red);     }     ...     More field validations here     ...     return bReturnVal; }   This doesn't display any color change at all. I'm not sure why it doesn't work. I would imagine I need to update the display, but I can't find how to do that.  I have also tried using OnCtlColor after finding this as a solution to many similar problems found with some Googling. This code looked like this:  HBRUSH myDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor) {     HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);      COLORREF red = RGB(255, 204, 204);      // TODO:  Change any attributes of the DC here     if (pWnd -> GetDlgCtrlID() == MY_CEDIT_ID && !myCEditIsValid()) {         pDC->SetBkColor(red);     }      if (pWnd->GetDlgCtrlID() == MY_OTHER_CEDIT_ID && !myOtherCEditIsValid()) {         pDC->SetBkColor(red);     }     ...     More field validations here     ...     //TODO:  Return a different brush if the default is not desired     return hbr; }   This one only paints the field with the current focus if it's invalid. None of the other invalid fields are painted.  If anyone could point me to a valid solution that will check all fields and paint them if they are invalid, I would greatly appreciate it.


Nondescript error message when user without enough rep to create tags attempts to suggest edit using not-yet-removed tag with zero questions

As of the instant this question was posted, the tag  has zero questions, but still exists in the system and has not been cleaned up yet. Just as a curiosity, I decided to test if users without enough rep to create tags could use such zero-question tags, and it turns out they can't.  However, the error message when doing so is a nondescript "An error occurred when submitting the edit":        Can this error message be changed to something more descriptive?  Update: Apparently, another such user was able to actually suggest an edit to add this very tag, without getting an error message:


Could somebody please help me out with articles?

Being Russian, I am having a fairly hard time understanding the concept of articles usage in various situations. Also it is hard to find truly elaborate manuals online. So here I would like to give an example that I find unclear.   1)  In fact, in one zoo, questions of animal safety arose when two red pandas were found dead after being exposed to rat poison. (Why is there no article required here before "rat poison"? Is it because the poison is an uncountable noun?)  2)  Let's talk about spoilers: why 'spoiler culture' is demeaning to the real power and beauty of film. (Why is there an article before "real power" here? I would assume that the word power is also uncountable)  Thank you!


Should I prioritize paying down my higher interest debt over building an emergency fund, or vice-versa?

I have a debt of $15,000 at a yearly interest rate of 9%, which can be paid within 5 years.  Would it be better for me to:   Build first the emergency fund (e.g. liquidity for 6 months' expenses without income) and then start repaying faster my debt, or Would it be better to just have a "mini" emergency fund (limited shorter term liquidity for, e.g. 1/2/3 months' expenses without income), in order to be able to repay my debt faster?


What is wrong with the following proof that tries to prove that $2=1$?

I need to find the flaw in the following proof:  $a,b\in\mathbb{R}$\ $\left\{ 0 \right\} $ such that $a=b$  1) Multiplying both sides by $a$ yields the equality: $a^2=ab$  2) Subtracting $b^2$ from both sides yields the equality $a^2-b^2=ab-b^2$  3) Then, $a^2-b^2=ab-b^2\Rightarrow (a-b)(a+b)=b(a-b)$  4) Then, dividing both sides of $(a-b)(a+b)=b(a-b)$ by $(a-b)$ yields: $a+b=b$  5) Substituting $a=b$ yields $2b=b$  5) Therefore, $2=1$    My thoughts and ideas on this:  It seems to me that step $5$ has an error. It should be that $a+b=b\Rightarrow a=0$. However, we initially said that $a,b$ cannot be $0$.


How to get the Raw pixel data from CGImage

How to get the Pixel Data of  UIimage after scaling and moving,I wan to get the CGImage Pixel Data and then get the UIImage from CGImage Pixel Data.How can we do this?.


Can I place more than 2 midoffs or 3-4 silly points in cricket? I have seen no match with such fieldings? But there are no rules against it.


Why is $balance not equal to 0.01 in if statement when the $balance is 0.01 above?

I have a problem with an if statement. The program doesn't go inside the if when it seems that the condition is true.  I tried to change the operator >= to == but it still doesn't work. It works with <= but I need >= and I also can't explain to myself why it's not working.  <?php  $balance = 0.03;      // input 0.03   if($balance >= 0.02) {     $returned = ((floor($balance / 0.02)) * 0.02); // 0.02     $balance = $balance - $returned;               // 0.03 - 0.02 = 0.01 left }  echo var_dump($balance) . PHP_EOL;  if($balance >= 0.01)                // why doesnt go in ? {     echo "Print Smt ...."; }   Why is the second if not true? Isn't 0.01 equal to 0.01?


Why is defragmenting unnecessary in Ubuntu?


How do I correctly make a .desktop file?

How do I make a .desktop file? I have tried making one our of another one, but it does not work. Can someone link me to a page on an entire guide to making one?


Derivative of an even function is odd and vice versa

This is the question: "Show that the derivative of an even function is odd and that the derivative of an odd function is even. (Write the equation that says f is even, and differentiate both sides, using the chain rule.)"  I already read numerous solutions online.  was the official solution but I didn't quite understand it (particularly, I'm not convinced why exactly $dz/dx=-1$; even though $z=-x$).  Thanks in advance =]


Why is Euler's Gamma function the "best" extension of the factorial function to the reals?

There are lots (an infinitude) of smooth functions that coincide with $f(n)=n!$ on the integers. Is there a simple reason why Euler's Gamma function $\Gamma (z) = \int_0^\infty t^{z-1} e^{-t} dt$ is the "best"?  In particular, I'm looking for reasons that I can explain to first-year calculus students.


If $a+b+c = 6$ and $a$, $b$, $c$ are nonnegative then $a^2+b^2+c^2 \geq 12$

Let $a,b,c$ be three positive real numbers such that $a+b+c = 6$. Prove that $a^2+b^2+c^2 \geq 12$.  I tried using the AM-GM inequality to solve the same, however I wasn't able to make any considerable progress.


Sufficient conditions for this function being linear

Let $f$ be a real-valued function for which, for every real $x,y$:  $$f(x+y) = f(x)+f(y)$$  Does this imply that $f$ is a linear function ($f(x)=a\cdot x$)?   If $f$ is differentiable, I think the answer is yes. Take the derivative of $f(x+y)$ by $x$: $f'(x+y)=f'(x)$. This is true for all $y$, hence $f'$ is a constant function. Additionally, $f(0)=f(x+0)-f(x)=0$. Hence $f(x)=ax$. (is this correct?) If $f$ is continuous, I think the answer is also yes. First, note that $f(0)=0$. Let $a=f(1)$. By addition, for every integer $x$, $f(x)=a\cdot x$. This also must be true for every rational $x$. Hence, by continuity, it must be true for all $x$. (is this correct?) What is the answer for general $f$?


Getting negative predicted values after linear regression

I'm using linear regression to predict a price which is obviously positive. I have only one feature which is gross_area. I standardized it (z-score) I got this kind of value:  array([[ 1.        , -0.48311432],        [ 1.        ,  0.68052306],        [ 1.        ,  2.1426852 ],        [ 1.        , -1.17398593],        [ 1.        , -0.16265712]])   Where the 1 is the constant for the intercept term. I predict the parameters(predictors) and I got this:  array([[ 31780004.85045217],        [ 27347542.4693376 ]])   Where the first cell is the intercept term and the second cell correspond to the parameter found for my feature gross_area.  My problem is the following, when I take for example the fourth line and I compute the matrix multiplication XB to get my prediction, I got this:  In [797]: np.dot(training[4], theta) Out[797]: array([-325625.35640697])   Which is totally wrong since I cannot have negative value for my dependent variable. It seems like because of my normalization where I got negative value for my feature, I ended up with a negative predicted value for some tuple. How can is it possible and how can I fix this ? Thank you.  This is what I have predict graphically:   with y=price , x =gross area


What distro or package manager allows non root to install?

Earlier I tried installing chrome (from a .deb file) on Debian using a non root account. I couldn't do it. Is there any distro or tools that will allow me to install chrome from a deb file and get its dependencies?


Prove convergence of alternating sequence with factorial in denominator $\frac{\left(-5\right)^n}{n!}$

How do I prove convergence of below alternating sequence with a factorial in the denominator?  $\{\frac{\left(-5\right)^n}{n!}\}$  How can I apply the principles described in  post to this question? What sequences can I use to apply Squeeze Theorem?


I have ubuntu 14.04 on my aws ec2 instance. I ran following command to find out the mysql-server installations and I got multiple results :   dpkg --get-selections | grep mysql     Now I would like to remove the one's not in use, so my question is how to find out which one is in use?  Noob Alert


Is there any infinite topological space $A$ which is connected such that $A$ and $A\times A$ are homeomorphic?


tikzpictures give huge pdf files when processed via dvips and ps2pdf

I have written a paper that includes a couple of TikZ pictures and submitted it to a (Springer) journal. I was quite shocked when I got the pdf file they produced from my source file, since it was over 8 MiB - while my own pdf is only 170 KiB.  First, I cut the pdf to single pages and found that the size comes from the TikZ pictures.  Then I realized that the journal most likely uses tex -> dvi -> ps -> pdf workflow, while I am using pdflatex. I therefore compiled the paper the other way and there it was: dvi file was 655 KiB, ps (via dvips) was 625 KiB, but pdf (via ps2pdf, or via ghostview) was 7.8 MiB. (The small difference is due to the journal adding a title page.)  Is there some way to produce a more reasonably-sized pdf file using the dvips-based route?  I tried adding \newcommand{\pgfsysdriver}{pgfsys-dvips.def} just before including tikz, but it did not do anything.  I also tried producing eps version of the figures, using the 'external' package to create poscript figures, but it is the same: for one of the figures, it is 12 KiB saved as pdf and 183 KiB as ps - which gives 183 KiB eps and then 3.1 MiB(!) pdf using epstopdf. (If I convert the 12 KiB pdf to eps in ghostview, I get 1.5 MiB eps, which then gives 361 KiB pdf using epstopdf - bit better, but still huge.)  edit: a working example:  \documentclass{article} \usepackage{tikz} \tikzstyle{strat}=[text=white, circle, ball color=red, inner sep=3pt] \tikzstyle{oper}=[text=white, rectangle, ball color=blue, inner sep=1.75pt, level distance=\lvlDist]  \newlength\lvlDist\setlength\lvlDist{12pt} % distance between levels  \begin{document} \begin{figure}[tbp]     \centering     \begin{tikzpicture}[level distance=\lvlDist, grow=down, every node/.style={oper}]         \path[                 level 1/.style={sibling distance=40mm},                 level 6/.style={sibling distance=20mm},                 level 7/.style={sibling distance=10mm},                 level 12/.style={sibling distance=5mm},                 level 13/.style={sibling distance=2mm}             ]             node[strat](root){} child foreach \oPI in {1,...,2} {                 node{} child { node{} child { node{} child {node{} child {                 node{} child foreach \perI in {1,...,2} {                     node[strat]{} child foreach \oPII in {1,...,2} {                     node{} child { node{} child { node{} child { node{} child {                     node{} child foreach \perII in {1,...,2} {                         node[strat]{} child foreach \oPIII in {1,...,2} {                         node{} child { node{} child { node{} child { node{} child {                             node{}                         }}}}}                     }}}}}}                 }}}}}             }         ;     \end{tikzpicture} \end{figure}  \end{document}   Pdflatex produces a 19 KiB pdf, while latex + dvips + ps2pdf give 209 KiB dvi -> 197 KiB ps -> 2954 KiB pdf.  Thanks


Trouble finding if a string exists in an ArrayList

Hey I am working on a project that enters in information for departments. This information includes, name, abbreviation, location, and number of members.  The first class I have accepts 8 parameters, (string, string abbrev, string, int, int, int, int, int, double).  It's added into an ArrayList and I'm having trouble testing to see if a string abbrev exists in any of those classes.  What I have as a method is:     private ArrayList<DeptInfo> dept = new ArrayList<DeptInfo>();     public boolean deleteDeptInfo(String abbrev) {    boolean result = false;   int index = -1;   for (DeptInfo test : dept) {      if (test.getAbbrev() == abbrev) {         index = dept.indexOf(test);         break;      }   }    if (index >= 0) {      dept.remove(index);      result = true;   }   return result; }


How do I fill my validAccounts array-it shows that there are null values in it

*How can i make sure my validAccounts array does not have null values?**  This program is an ATM program that uses a text file and checks to see if the user's password and account number matches the possible passwords and balance from the text file    import java.util.*;  import java.io.*;   public class ATM2 {  public static Scanner kbd;  public static final int MAXSIZE = 60000;  public static void main(String[] args) {     kbd = new Scanner(System.in);     Scanner input = null;     String[] validAccounts = new String[MAXSIZE];     int lineNum = 1;     try {         input = new Scanner(new File("ATMdata.txt"));         // counts how many lines are in text         while (input.hasNextLine()) {             String line;             line = input.nextLine();             lineNum++;          }         // sets the array to the number of lines in text         validAccounts = new String[lineNum];         // prints out the number of lines in text         System.out.println(lineNum);          input.close();      }      catch (FileNotFoundException e) {         System.out.println("There was an error opening one of the files.");     }      try {          int count = 0;         input = new Scanner(new File("ATMdata.txt"));         // counts how many lines are in text         while (input.hasNextLine()) {             String line;             line = input.nextLine();              validAccounts[count] = line;             count++;          System.out.println(line);         }         input.close();      } catch (FileNotFoundException e) {         System.out.println("There was an error opening file");     }      System.out.println("What is your account number?");     String acctNum = kbd.nextLine();     System.out.println("What is the password?");     String pwd = kbd.nextLine();      checkID(acctNum,  pwd,validAccounts);     }  // Each entry in the validAccounts array is assumed to be holding: // the account number followed by // a space, followed by // the password for the account // followed by a space // followed by the current balance.  public static String checkID(String acctNum, String pwd,         String[] validAccounts) {     String account = "" ;     String password = "" ;     String balance;  String result = "error";  //This is supposed to check the array for a valid input for(int i = 0; i <validAccounts.length ; i ++){     **//It is giving me an error for the line below-if anyone could help me figure it           out!**     int space1 = validAccounts[i].indexOf(" ");//ERROR     account = validAccounts[i].substring(0, space1);     int space2 = validAccounts[i].indexOf(" ", space1 + 1);     password = validAccounts[i].substring(validAccounts[i].indexOf(" ") + 1, space2);     balance = validAccounts[i].substring(validAccounts[i].lastIndexOf(" ") + 1);  } if (acctNum.equals(account)){     return account; } if(pwd.equals(password)){     return password;   }       return result; }   }


Regular expression matching multiple entries, spanning multiple lines

I'm fairly new to regular expressions and what I'm trying to achieve seems impossible after a few hours of trying. I could not find similar issues, so that is why I am making a separate question; please excuse me if there is already a question like that.  Now. I want to match every occurrence of the regular expression throughout the document; the occurrences are spanning multiple lines. Here is an example:  // javascript.js  /**  * #start?  * @name myFunction(p1)  * @desc Description of the function  * @param p1 : int = Parameter of type int  * ...  * #end?  */ function myFunction(p1) { ... }  /**  * #start?  * @name yourFunction()  * @desc Description of the function  * ...  * #end?  */ function yourFunction() { ... }   With the regular expression I would like to match the comment sections that describe the functions, from #start? to #end?. As a result I want to have 2 matched occurrences - the description of the first function and that of the second one.  What I came with is (#start\?)[\s\S]+(#end\?), but as you can guess it matches the first #start? and closes the match with the second #end?  How can I make it match all similar comment sections as separate occurrences?  Thank you very much for your time!  Update/Solution As pointed out by Wiktor Stribiżew - lazy != greedy The working regular expression for this case is (#start\?)[\s\S]+?(#end\?)


Two Craigslist “Buyers” were trying to scam me

I posted an item I was selling on Craigslist. This is two different buyers who want to buy my item. One was $150 and the other was $100. And these two separate buyer had sent me a check that was over $1000. I checked my email to inform them then they had said the EXACT same thing. They both wanted me to run by the money gram and send the rest of the money to some person’s address (two different person’s address). I already know that this is a scam; what should I do?


If two ends were a certain "length" apart were they therefore at rest (or at least rigid) to each other?

Considering the definition of the SI unit of "length" [1] and [2 (" method a.")] I'm missing any requirements about the two "ends" of the required "path travelled by light" being "at rest to each other", or at least "rigid to each other".  Are such requirements perhaps presumed to be understood implicitly?  Accordingly, if some particular pair of "ends", $A$ and $B$, in some particular trial, were characterized as having been a certain "lenght of $x \, \text{m}$ apart from each other", where "$x$" is some particular positive real number and "$\text{m}$" denotes the SI base unit "metre", is it then understood:   that ends $A$ and $B$ had observed exchanging signal pings between each other; and not only once for each trial, but for any of their signal indications throughout a sufficiently extended trial?, that for any two (distinct) signal indications $A_J$ and $A_K$ of end $A$ during this trial the corresponding ping durations of end $A$ were equal to each other: $\tau_A[ \,_J, \,_{\circledR}^{B \circledR AJ} ] = \tau_A[ \,_K, \,_{\circledR}^{B \circledR AK} ]$ ?, that for any two (distinct) signal indications $B_P$ and $B_Q$ of end $B$ during this trial the corresponding ping durations of end $B$ were equal to each other: $\tau_B[ \,_P, \,_{\circledR}^{A \circledR BP} ] = \tau_B[ \,_Q, \,_{\circledR}^{A \circledR BQ} ]$ ?, and that for any signal indications $A_J$ of end $A$ and any signal indication $B_P$ of end $B$ during this trial the corresponding ping durations were equal to each other: $\tau_A[ \,_J, \,_{\circledR}^{B \circledR AJ} ] = \tau_B[ \,_P, \,_{\circledR}^{A \circledR BP} ] = \frac{2 x}{c} \text{m} $ ?.   References: [1] SI brochure (8th edition, 2006), Section 2.1.1.1;  ("The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.").  [2] "the mise en pratique of the definition of the metre";


How to show/hide special folders in home directory nautilus

In nautilus home folder shows some special folders like:  Music,Documents,Pictures etc.  Most of the time I am not interested in browsing these directories.  Is there any way to toggle the visibility of these type of folders in home directory? Is it possible to show files and folders in groups(Like in Window Vista).   Note that this is not same as .


I am trying to remove item from list but I am gettin Concurrent Modification Exception?

This is the place which I am going to remove my item,  myhieararchy hierarchyforDisplay = null;      try {          hierarchyforDisplay = (myhieararchy)hieararchybefore.clone();      } catch (CloneNotSupportedException e) {          e.printStackTrace();      }      for (Project project : projectList) {      for (Program program : hierarchyforDisplay.getPrograms()) {          for (Project rootproject : program.getProject()) {              if(project.getId() != rootproject.getProjectId()){                  program.getProject().remove(rootproject);             }         }     }     }       return hierarchyforDisplay;   But I am getting this  org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.util.ConcurrentModificationException org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:656) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549) javax.servlet.http.HttpServlet.service(HttpServlet.java:621) javax.servlet.http.HttpServlet.service(HttpServlet.java:722)   I can not imagine what is the reson because this is my first time I get this.. :(


How to get the json data under the script tag using html dom?


So I get that work is done when a net force converts potential to heat or kinetic. But I also understand that osmosis is driven purely by entropic processes. There is no net force, only a statistical change driven by random motion. So where does the energy, aka osmotic power or pressure actually come from. It seems contradictory that it is purely entropic yet releases free energy.


Unwanted Lines when rendering using GPU and OpenCL (RX 580)

I'm new to blender and have been studying and starting with low poly modeling. Recently I changed my GPU from a GTX 960 to an RX 580. I uninstalled the drivers and installed new ones using DDU.  Problem: Rendering using OpenCL produces these unwanted lines. The attached image is a product of CPU + GPU render then the GPU only render, respectively. When I render using only the CPU the results are as expected, no unwanted black vertical lines, using only the GPU adds more lines on the image.  Any help is appreciated, thank you!


If the set of odd numbers is a subset of $\mathbb N$ then surely it is smaller than $\mathbb N$

I have been studying Cantor's theorem, and I follow entirely that the set of natural numbers $\mathbb{N}$ is countable, as is the set of odd numbers (let's call it $\mathbb{O}$).  I understand his proof that there is a correspondence between the two sets and feel like I could accept that they therefore have the same cardinality based on that ... but ... hold on ...  We know that $\mathbb{O}$ is a subset of $\mathbb{N}$ right? $\mathbb{N}$ certainly contains all of the odd numbers.   We also know that $\mathbb{N}$ contains numbers that are not odd.   So if $\mathbb{N}$ contains all of $\mathbb{O}$ and some other stuff as well then surely it would be totally justified to argue that $\mathbb{N}$ is larger than $\mathbb{O}$?


I have a horizontal navbar like the following:

About

Contact

   I use CSS to remove the bullet points and make it horizontal.  #Navigation li {     list-style-type: none;     display: inline; }   I'm trying to justify the text so each link is spread out evenly to fill up the entirety of the ul's space.  I tried adding text: justify to both the li and ul selectors, but they're still left-aligned.  #Navigation {     text-align: justify; }  #Navigation li {     list-style-type: none;     display: inline;     text-align: justify; }   This is strange, because if I use text-align: right, it behaves as expected.  How do I spread out the links evenly?


Empty /home directory, and I can't delete it?

I have got a /home directory with no content. When trying to delete it by sudo rm -rf /home, OS X warns "rm: /home: Resource busy" and refuses to do it.   Tried reboot. lsof returns nothing related.  Does anyone know why could this happen, and, especially, how can I remove it?


Proof of the Absolute Least Remainder Algorithm

I have managed to grasp and construct the elementary proofs of the division theorem and the modified version were $0 \leq r < \mid b \mid $, but I am not quite there yet with the absolute least remainder algorithm.  Theorem:  If $a, b \in \mathbb{Z} $ and $a, b \neq 0$, then there are unique $q, r \in \mathbb{Z} $ such that:  $a = bq +r, ~~~~ -\frac{|b|}{2} < r \leq \frac{|b|}{2}$  Proof:  (here is what I got so far)  There are three things to prove: existence, r conditions and uniqueness.  Consider these two cases:    $0 \leq r < \frac{1}{2} |b| $ $\frac{1}{2} |b| \leq r < |b|$   We apply the original division algorithm to a.  In the first case, we have:  $a = |b|q' + r$  where $q' = q \frac{|b|}{b} \in \mathbb{Z}$ and $r$ is in the appropriate range.  In the second case, we have:  $a = |b|q' + r'$ where $q' = (q+1) \frac{|b|}{b} \in \mathbb{Z}$ and $r' = r - |b|$.   This satisfies the r' criteria i.e. $-\frac{1}{2}|b| \leq r' < 0$.    However, I am not sure if this is correct in the first place, or how to connect this to the overarching proof structure of the division algorithm.


Excel using INDEX and LIST to return multiple results

I'm trying to use Excel with the INDEX and LIST functions (rather than VLOOKUP) as I am trying to return multiple results from one worksheet into another.  I've got close with the following formula: =INDEX(Sheet1!A2:AJ100,MATCH(B1,Sheet1!O2:O100,0),1) but it is only returning 1 result, how would I return the list of results within the Sheet1!A2:A100 range which match the content of B1 against the data in Sheet1!O2:O100 range?  The range of data I want to retrieve will be unique, the matching criteria won't be.  Multiple website about matching multiple criteria and returning 1 result, but very few about multiple matches to 1 criteria and returning all the results. Thanks


I have binary data in an unsigned char variable. I need to convert them to PEM base64 in c. I looked in openssl library but i could not find any function. Does any body have any idea?


Why did Community suddenly delete posts in bulk about an hour ago?

I just opened up Stack Overflow, and realized I had a -4 in my reputation. I thought I'd been downvoted, and clicked on the two posts that showed the -4. Turns out, I hadn't even answered these posts, but edited them back in '12 when I didn't have edit privileges. Both of these posts had been deleted by Community an hour ago.  I went into the 10k tools and found a fair amount of posts deleted by Community (both with and without answers. Granted, none of the deleted questions were all that good, but I would like to know why they were specifically deleted now? Is there some sort of cleanup script that runs every now and then, or something else?  Here's a list of the questions I could find:


How to calculate the signal-to-noise ratio (SNR) in an image?

I am working with an image X, I apply the "adaptive median filter" in it and I get the image Y. I'd like to measure the SNR in both in order to evaluate the quantity of noise deleted.   I know the formula to calculate the SNR is:   SNR = Psignal / Pnoise  but I don't know how to get these values from both images I have. I was thinking in substract the image X from Y and get the noise value. But I am not sure about the method.


Why does "1" == 1 return true in Javascript?

I'm trying to learn more about this liberal language and a good explanation would be awesome.  Thanks!


Panicking Internally vs Internally Panicking?

Which order (Panicking internally/ Internally panicking) is correct or more widely accepted and why?


Proof:"Infinite subset of $\mathbb N$ is countable

I've read a proof of the statement:"An infinite subset of $\mathbb N$ is countable; that is, if $A \subset \mathbb N$ and if $A$ is infinite, then $A$ is equivalent to $\mathbb N$." in Carothers' textbook and there is one part of the proof I don't understand. Proof Recall that $\mathbb N$ is well ordered. That is, each nonempty subset of $\mathbb N$ has a smallest element. Thus, since $A \ne \emptyset$, there is a smallest element $x_1 \in A$. Then $A \setminus \{x_1\} \ne \emptyset$, and there must be a smallest $x_2 \in A \setminus \{x_1\}$. But now $A \setminus \{x_1,x_2\} \ne \emptyset$, and so we continue, setting $x_3=\min(A \setminus \{x_1,x_2\})$. By induction, we can find $x_1,x_2,x_3,...,x_n,... \in A$, where $x_n=\min(A \setminus \{x_1,...,x_{n-1}\})$. How do we know that this process exhausts $A$? Well, suppose that $x \in A \setminus \{x_1,x_2,...\} \ne \emptyset$. Then the set $\{k : x_k>x\}$ must be nonempty (otherwise we would have $x \in A$ and $x<x_1=\min A$), and hence it has a least element. That is, there is some $n$ with $x_1<...<x_{n-1}<x<x_n$. But this contradicts the choice of $x_n$ as the first element in $A \setminus \{x_1,...,x_{n-1}\}$. Consequently, $A$ is countable. My questions It is affirmed that the set $\{k : x_k>x\}$ can't be empty (I don't get the reason Carothers gives for this being impossible). As I see it, if $\{k : x_k>x\}$ is empty, then $x_k \leq x$ for all $k$. So the set $\{x_1,x_2,...\}$ obtained by the method of extracting the smallest element from each remaining nonempty subset of $\mathbb N$ is finite, but we've seen that the set constructed from choosing $x_n=\min(A \setminus \{x_1,...,x_{n-1}\})$ is infinite. So, wouldn't this be the reason why the set $\{k : x_k>x\}$ can't be empty rather than "otherwise we would have $x \in A$ and $x<x_1=\min A$"?. I couldn't even understand why would $x$ be in $A$ instead of $x \in A \setminus \{x_1,x_2,...\}$ or why $x<x_1$. I know it is a very small part of the proof but I would like to understand all the steps of it so I would appreciate if someone could clear up my doubt.


Im having problems creating a schedule job in SalesForce. i have this class:  global class dollarGetSC implements Schedulable { global void execute(SchedulableContext sc)     {          dollarGet.makeGetCallout();  } }   Im creating this for the job:  dollarGetSC sc = new dollarGetSC(); string cronExp = '0 0 22 * * ? *';  // 8:00am every day string JobId = system.schedule('GETTING Dollar', cronExp, sc);   But it doesnt do nothing   If i call dollarGet.makeGetCallout(); works fine and i want to do it automatically through apex job but it doesn't work.  I get this error: Scheduler: failed to execute scheduled job: jobId: 7070j00000O5bWX, class: common.apex.async.AsyncApexJobObject, reason: Callout from scheduled Apex not supported. What am i doing wrong?


Convergence of series $\sum_{n=1}^{\infty} \frac{a_n}{s_n}$

Let $\sum_{n=1}^{\infty} a_n$ be a divergent series of positive terms and $\{s_n\}_{n=1}^{\infty}$ denote the sequence of it's partial sums. Test the convergence of the series $\sum_{n=1}^{\infty} \frac{a_n}{s_n}$.  Attempt: Since $\sum_{n=1}^{\infty} a_n$ be a divergent series of positive terms, $\{s_n\}_{n=1}^{\infty}$ is unbounded.what to next, I have no idea, So I need help.  Thank you.


Is it possible to add new predictions/autofill in Overleaf?

For example, when I use the command (in Overleaf/ShareLaTex):  \begin{figure}[H]     \centering     \includegraphics{some_graphic}     \caption{some_caption}     \label{fig:some_label} \end{figure}   the \includegraphics{} comes without the [] parameter to change the size of the image, and \begin{figure} without the [H] option by default.   Is it possible to renew the command to make it default? By that I mean that when I type the \begin{figure} command it adds the [H] and [h] as well as [width=\textwidth] in the \includegraphics command, rather than making a global change in the preamble e.g.


I've noticed a lot of people ask this question, but I just don't understand. If the number next to the name is the seasonal rank like people say, how can someone have a level of 222 or 261? Seasonal ranks only go up to 100.


Use of gerund vs bare-infinitive: overfilling vs overfill

How do I explain using "overfilling" instead of "overfill" in the following sentence?      We needed to announce the party just a few days from the date to avoid overfill the salon.


Separate labels in dcases lines and then reference to them

I use of mathtools package and dcases environment. Ideally, I would like to be able to write something like below:  \documentclass[12pt,a4paper]{article} \usepackage{amsthm,amssymb,amsmath,mathrsfs}  \usepackage{mathtools}  \begin{document} \begin{equation} f(x)=\begin{dcases}   1&x\geq0\label{positive}\\   0&x<0\label{negative} \end{dcases} \end{equation} \end{document}   and later refer to both dcases lines at different places. What would be the best way to achieve this result?


Please show me how to use "not in" using LINQ  Given the SQL :   select count(*) from Customer where (ID = @Id and substring(CustomerIndicator, 1, 1)  not in(@custInd1, @custInd2, @custInd3))   My Attempt:          var results = (from r in dt.AsEnumerable()                        where r.Field<string>("ID") == row["ID"].ToString()                             && !(r.Field<string>("CustomerIndicator").Substring(1, 1) == "X" || "Y" || "Z")                        select r).Count();


My app is currently trying to connect a user and customer and here I am trying to do this via Firebase and GeoFire. However for some reason this switch is throwing me   2020-03-20 01:13:13.614 14508-14508/swift.fix.application I/Choreographer: Skipped 62 frames!  The application may be doing too much work on its main thread. 2020-03-20 01:13:13.907 14508-14508/swift.fix.application D/AndroidRuntime: Shutting down VM 2020-03-20 01:13:13.935 14508-14508/swift.fix.application E/AndroidRuntime: FATAL EXCEPTION: main     Process: swift.fix.application, PID: 14508     java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference         at swift.fix.application.TradesmanMapActivity$4.onLocationResult(TradesmanMapActivity.java:180)         at com.google.android.gms.internal.location.zzau.notifyListener(Unknown Source:4)         at com.google.android.gms.common.api.internal.ListenerHolder.notifyListenerInternal(com.google.android.gms:play-services-base@@17.1.0:17)         at com.google.android.gms.common.api.internal.ListenerHolder$zaa.handleMessage(com.google.android.gms:play-services-base@@17.1.0:6)         at android.os.Handler.dispatchMessage(Handler.java:106)         at com.google.android.gms.internal.base.zar.dispatchMessage(com.google.android.gms:play-services-base@@17.1.0:8)         at android.os.Looper.loop(Looper.java:193)         at android.app.ActivityThread.main(ActivityThread.java:6669)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)   The app crashes when I select to be a user, and crashes the app. I have looked through to see if I am missing a CustomerID somewhere but can't see anywhere. The stand out is the NullPointerException error.  switch (CustomerID){                     case "":                          geoFireWorking.removeLocation(UserID, new GeoFire.CompletionListener() {                             @Override                             public void onComplete(String key, DatabaseError error) {                              }                         });                         geoFireAvailable.setLocation(UserID, new GeoLocation(location.getLatitude(), location.getLongitude()), new GeoFire.CompletionListener() {                             @Override                             public void onComplete(String key, DatabaseError error) {                              }                         });                          break;                     default:                         geoFireAvailable.removeLocation(UserID, new GeoFire.CompletionListener() {                             @Override                             public void onComplete(String key, DatabaseError error) {                              }                         });                         geoFireWorking.setLocation(UserID, new GeoLocation(location.getLatitude(), location.getLongitude()), new GeoFire.CompletionListener() {                             @Override                             public void onComplete(String key, DatabaseError error) {                              }                         });                          break;                 }   I am not sure what I am missing and it is really bugging me as I assumed it was correct :(


Some proof question about Fibonacci sequence

The Fibonacci sequence as $f(n)$   (1) show that $f(n) \le (\frac{7}{4})^n$, for all$ n \ge 0$  (2) show that $f(n) \ge \frac{1}{3}(\frac{3}{2})^n$, for all $ n \ge 1$  thanks.


Club filter of $\kappa$ is $\kappa$-complete

I'm trying to show that club filter of $\kappa$ is $\kappa$-complete for uncountable regular cardinal $\kappa$:  Let $\kappa$ be uncountable regular cardinal, let $C(\kappa)$ be the club filter generated by $\kappa$.  To show that $C(\kappa)$ is $\kappa$-complete it is enough to show that for every sequence $\langle \alpha_i\mid i<\gamma\rangle$ with $\gamma<\kappa$ and $\alpha_i$ club of $\kappa$ the set $\alpha=\bigcap_{i<\gamma}\alpha_i$ is a club of $\kappa$.  Showing that $\alpha$ is close is easy:     If $\beta_n$ is a sequence in $\alpha$ then for every $i$ we that $\beta_n$ is a sequence in $\alpha_i$, because $\alpha_i$ is a club it is close hence $\lim \beta_n$ is in $\alpha_i$ for every $i$ so it is also in $\alpha$   But I have a problem with unboundedness, my guess will be for each $\lambda<\kappa$ to find a sequence for each $\alpha_i$ such that all of the sequences converge to some $\mu>\lambda$, that way $\beta<\mu\in\alpha$. I think I'll have to use the fact $\kappa$ is regular, but I don't know how to proceed and prove my idea.  So, is my idea correct, and if yes how can I proceed?


Book on designing clinical trials in oncology

I would like to have a good idea on how to design clinical trials in oncology. In that issue, I am looking for a compact book that could give me a good overview, with the emphasis on statistical considerations. Would you have a recommendation for me?  Thank you in advance, Marco


What happened to "anonymous user feedback"?

What happened to ?  Now when I visit a Stack Exchange site as an anonymous user, I can't find a feedback button. Where did it go?


How to use the Central Limit Theorem when you don't know the variance

Given independent and identically distributed (not necessarily normal) random variables $X_1, \dots, X_n$ with unknown mean $\mu$ and unknown variance $\sigma^2$, the  states that the sample mean (equiv. sum) approximately follows a normal distribution. In particular, we have that $$ \frac{\bar{X}-\mu}{\sigma/\sqrt{n}} \sim \mathcal{N}(0,1) $$ as the sample size $n$ gets large. Armed with this knowledge, we can create a level-$\alpha$ confidence interval for the mean: $$ \bar{X} \pm z_{1-\alpha/2}\frac{\sigma}{\sqrt{n}} $$ where $z_{1-\alpha/2}$ is the appropriate quantile of the standard normal distribution.  However, this interval depends on the population value $\sigma$ (equiv. $\sigma^2$); when we observe a sample, we don't know this value. What we do observe is the sample variance $S^2=\frac{1}{n-1}\sum_{i=1}^n(X_i-\bar{X})^2$, but my understanding is that $S^2$ doesn't follow a chi-square distribution unless the original $X_i$ came from a normal distribution (which is not part of our assumptions or else we don't need the CLT). So, we can't simply replace $\sigma$ with $s$ and $z_{1-\alpha/2}$ with $t_{1-\alpha/2;\ n-1}$ in our confidence interval.  My question is: how do we use the CLT to create a confidence interval if we don't know the population variance?  EDIT: In this question, one of the answers simply replaces $\sigma$ with $s$ and $z$ with $t$ like I mentioned above. Is this inaccurate?


How to avoid weekends or holidays when adding or subtracting days from a date

I have seen this question in many formats, including C/C+ and Javascript. I've also seen this question in it's converse form... . But, just suppose you already have a specific date. Let's say, for example, 2014-01-04 and I would like to calculate a date ($diff) three WORKING days before that excluding any weekends or holidays. A direct subtraction of three days would result in 2014-01-01, so we know that won't work. So, I subtract another day and get 2013-12-31 - again, no good. Another attempt gives us 2013-12-30. Finally, we have three ACTUAL WORKING DAYS between the two dates!! But, let's just say that as it will in 2014, 2013-12-30 falls on a Sunday.... man, oh man - shafted again! Well, I think you get my point here. How in the world do I get the results I want?


I am trying to find out how inflammatory markers change in response to a mechanical device change. I have daily readings for the 5 days before the event and for the 5 days after the event. I am expecting a rise in inflammatory markers in the pre readings followed by a fall after the device change. I also need to find out how the change differs in two subgroups (sample sizes of the subgroups are n=21 and n=88). The aim is to find out if the change is significant, to consider these markers as predictors of the device failing and hence needing to be changed.    I would like to know what test would be appropriate to analyse this. I need to keep things simple as I and the people reading the results are non-statisticians.


Will Ubuntu use my full RAM in dual boot?

When I run Ubuntu in dual boot will I still be able to use my full 4 GB RAM if I am not running Win 7 at the same time?


How can I take a site offline using Drush?


Why do we now say 'Ukraine' and no longer 'the Ukraine'?


Can Freestyle draw lines between intersecting meshes like SoftImage?

I used a translator.  Please understand if I wrote the wrong sentence  I think the last question is difficult to understand. So I Attached was a picture.  The problem of the picture 1 and 2. I want to resolve, as the third picture.  And fourth and fifth picture is a way to resolve in a soft image. So I want to know that possible a blender  tool solve same problem.  I'm sorry to bother you. But I'm really need your help.    I used translator.  Photo 1 problem occurred twice.  I want to solve as picture 3  The Softimage picture is 4 to 5 times.  4 Blender 5 times as possible too.  The request help.


How to calculate this normal distribution

I have this mass of probability is proportional to $$exp[-\frac{\beta}{2}\parallel x-Hz\parallel^{2}-\frac{\alpha}{2}z^{t}C^{t}Cz]$$ and I have to calculate to its distribution but I don't know how, its distribution is $$\mathcal{N}((\alpha C^{t}C+\beta H^{t}H)^{-1}\beta H^{t} x,(\alpha C^{t}C+\beta H^{t}H)^{-1}.$$ $z$ and $x$ are vectors and $H$ and $C$ matrices, Any idea?


Alternative to form with long list of double checkboxes?

I'm stumped by this one. Redesigning a large web app and one piece of the interface was this, where the user can select how they want to be notified by various things. I doctored the screenshot to keep the app private - really the list goes on for about a dozen rows. It's kinda ridiculous and I was just wondering if anyone has seen an alternative to this dilemma, because I haven't. The various things to be notified about have no correlation so you can't group them together. The only other thought I had was possibly converting the checkboxes into toggle switches. Perhaps there's a 3-point toggle switch that wouldn't suck?


Express redirect sending page as data to success of angular $http instead of redirecting to the page

When the user is validated the client get the page contents of home.html in result instead of redirecting to the home.html.  Client side call:  $http({ method: "post", url: "http://localhost:2222/validateUser", data: {     username: $scope.username,     password: $scope.password }  }).then(function (result) {     if (result.data && result.data.length) {         alert('User validated');     } else {         alert('invalid user');     } });   Server side controller method:  module.exports.validateUser = function (req, res) {   User.find({ 'username': req.body.username, 'password': req.body.password }, function (err, result) {     if (result.length) {         req.session.user = result[0]._doc;         res.redirect('/home');     }else{         res.json(result);     }   }); };   Route in app.js:  app.get('/home', function (req, res) {     var path = require('path');     res.sendFile(path.resolve('server/views/home.html')); });


Can i create a shared folder between ubuntu 13.10 and windows 8.1

I have a dual boot system with ubuntu 13.10 and windows 8.1. At times i can access windows file from ubuntu but not ubuntu files from windows. is there an option to create a shared folder so that i can put the common files in it and access from both ubuntu and windows when necessary


Apple OSX with JVM support (or any virtual machine)

Few things I didn't understand on OS X...  From 2010 until today...   Throughout the internet there were several sources stating that according to Apple's EULA it wasn't legal to run any virtual machine (including JVM) on OS X 10.5 and above. As time passed, internet sources stated that JVM shipping with OS X was deprecated only and Oracle took over the updates.   Currently, is it legal to run JVM on OS X? If so, does Apple supports it?  EDIT: All Apple's i-devices will never run JVM (at least not support it). I don't know what's the future on this issue, but it seems that there JVMs for i-devices, but are they legal?


Old horror movie with creatures eating all matter in the past

I remember watching this as a child, it was very scary for me, I had nightmares. I think it's around 25-30 years old.  It's happening on an airport, there is some time traveling included I think, and then some huge round creatures with mouths full of scary teeth like saws appear and eat everything.


Looking for a book about small wormholes used for viewing other places/times

I'm looking for the title of a book where somebody created the ability to make small wormholes. These wormholes were so small, they wouldn't be seen by the naked eye. They were one directional, meaning light could only travel through in one direction, allowing only viewing, like a telescope, through the wormhole.  Later in the book it was discovered that these wormholes could also connect to times in the past (not future) revealing any and all secrets.


I have a two columns document. And I to force a figure into a full paper width.  I tried this:  \begin{center}    \makebox[\textwidth]{\includegraphics[width=\paperwidth]{figures/reviewprocessmodel}}  \end{center}   But the figure overlaps with the text. any ideas!


Why is a question with no close votes in the Close Votes review queue?

I just came to  (on Workplace) in the Close Votes review queue, where I was asked if it should be closed as a duplicate of another question.  When I went to vote, however, I was surprised to find no trace of other close votes; usually you see how many votes for each reason have been cast.  I then went to the question page -- no close votes shown.  I suspect that somebody voted to close (kicking it into the queue) and then retracted the vote.  But shouldn't that have removed the question from the queue?  Or will it eventually and the answer is "because caching"?


I tried to add an alias in the bash but I think I deleted something as I now can't see no user in my terminal..  I did vim ~/.bashrc Then e to edit the file and edited on the last line where I added an alias.  Hit Esc and :wq , but then my terminal was blank...  Anyway to fix this??


How to add angled tick marks to a path, illustrating a solid wall

I want to use tikz to draw a line with hatch marks/angled ticks to illustrate a solid wall (as shown in the image). This seems like it would be useful feature that would have a solution. I have tried searching the decorations library to no avail.


Is it correct to use softwares, as in the following sentence?  There are various video conversion softwares in the market.


Why does the compiler warn me if I pass an array of non-const elements?

Marking a location as const is a sort of “downgrade”: everything can become const but the other way around cannot happen. So if I pass a non-const string to a function that requires a const string no problem, but if I do the opposite the compiler will warn me. Hence this code works fine: #include <stdio.h>  void print_constant_string (const char * const str) {     printf("%s\n", str); }  int main () {     char * my_string = "Hello world!";     print_constant_string(my_string);     return 0; }  What I never understood is why this code instead gives me a warning (“warning: passing argument 1 of ‘print_array_of_constant_strings’ from incompatible pointer type [-Wincompatible-pointer-types]”): #include <stdio.h>  void print_array_of_constant_strings (const char * const * const strarr) {     for (size_t i = 0; strarr[i]; printf("%s\n", strarr[i++])); }  int main () {     char ** my_array = (char * []) { "foo", "bar", NULL };     print_array_of_constant_strings(my_array);     return 0; }  Am I not “downgrading” my variable exactly as I did before? What could possibly go wrong if the compiler did not warn me?


How do I make my text vertically centered when height increases?

my html file: <!DOCTYPE html>      <meta charset="utf-8">   <title>Using Web Font</title>   <link rel="stylesheet" type="text/css" href="style.css">
Making the Web Beautiful!
     my css file: html, body {   font-size: 40px;   text-align: center;   padding-top: 3.5em; }  @font-face {   font-family: 'Dancing Script';   font-style: normal;   font-weight: 500;   font-display: swap;   src: url(https://fonts.gstatic.com/s/dancingscript/v15/If2cXTr6YS-zF4S-kcSWSVi_sxjsohD9F50Ruu7BAyo3Sup8.woff2) format('woff2'); }  .paragraph {   font-family: 'Dancing Script';   font-style: normal;   font-weight: 500;   font-display: swap;   border-width: thick;   border-style: dashed solid;   border-color: red rgba(170, 50, 220, .6) green;   display: inline-block;   width: 9em;   margin:0 auto;   height: 10em;   vertical-align: middle; }  Result:  As the height of .paragraph increases, the text won't change its position to be vertically centered again. Is there a way to make the text vertically centered as the height changes? I'm new to coding so I am really not sure... It would be great if I can get some help! Thanks


How long can you keep polyjuice potion before it is no longer usable?

Harry, Hermione and Ron possess a reserve of polyjuice potion when they go in search of Horcruxes.  It takes months and they use it three times:   to go to the Ministry of Magic, to go to Godric's Hollow, to go to Gringotts.   Would this mean the potion always keeps its properties/potential  as long as you haven't added the hair of the person you're turning into.


How to analyze data with more than one associated categorical dependent variables?

I have some dependent variables related to the growth of a company having categories like (e.g. for variables indicating net profit, financial turnover etc.)   (1) decreasing,   (2) stable,   (3) increasing and   (4) rapidly increasing.  Now these variables are associated and ordinal in nature. I want to see the effect of a set of co-variates on these dependent variables. I understand that separate logistic regression will result in wrong formula of the variance and thus will produce wrong p-values. But what kind of regression should I run with more than one associated dependent categorical variables? Should that be a GEE model? Or anything else like multivariate regression (GLM)?   Can SPSS or R perform this?   Besides, I would like to have your suggestion regarding whether I should rather consider these variables as nominal and take "stable" as the reference category so that interpretations are more meaningful?  Kind regards.


Bloated transaction log and .bak backup size confusion

I recently inherited a poorly-managed SQL server.  One of the databases is in rough shape. Here are the details:   The .mdf file is a modest 369MB. The .ldf file is a bloated 29.7GB. The recovery model is set to FULL. The data file is backed up nightly without issue, and is 365MB. The transaction log has NEVER been backed up.   I've restored the nightly backup to the same SQL server and poked around in it to make sure data looks to be intact. When I restore that nightly .bak backup file it recreates the .mdf and .ldf files at 369MB and 29.7GB, respectively.  Being decent with SQL, but not what I would call an expert by any means, I have a few follow up questions on this situation that I am hoping to get feedback on:   How is a 369MB .bak file restoring both a 369MB .mdf file and a 29.7GB .ldf file? Any suggestions on what to do regarding the recovery model and bloated .ldf file? We are only concerned about doing backups once nightly - we don't need to do differential backups at this time - but it's something I will tackle later.


Looking for two sides in a right triangle where the perimeter is known

The perimeter in a right triangle is known and also one side. Am I right thinking that the hypotenuse and the other side can only have one set of lengths?  Using Geogebra I was able to approximate the lengths but I wonder if someone can help me find a formula.


apacite bibliographystyle and footnote citations

I seem to have lost the overview about my bibliographystyle and citation in footnotes. I am in dire need of your help. What I would like to achieve, is to have the bibliography in APA-Style, exactly like , and inside the text, to cite with footnotes that show the following: Author. (year), p. 375  Here is my the relevant code that I use so far. As you can see, I already use footnote citations, but unfortunately, without the desired bibliographystyle apacite yet. How can I combine the two?  \documentclass[12pt]{report}  \usepackage[style=authoryear,autocite=footnote, backend=bibtex]{biblatex} \bibliography{biblio}   And here an example of a citation command I use, where [23] is the page number:  \autocite[23]{corpore21}   Thsi gives me the following citation in a footnote: Pieth 1997, p. 23.  In advance, many many thanks for helping me out.


What does having an imaginary part of potential imply?

In DJ Griffiths' ''Introduction to Quantum Mechanics" to describe an unstable particle that spontaneously disintegrates he assumed an imaginary part in the potential. What does that signify? What is meant by an imaginary potential? I have added the image of the problem.


Does a plumbing vent need to penetrate the roof? (Can it penetrate a wall?)

We're going to move our washer/dryer to the garage (the front loader needs to sit on  concrete to keep it from shaking our house to the ground).   I'll need to add a washer drain to the garage for the washer. Because this will need a p-trap, my understanding is that it also needs to be vented.   I could go straight up into the attic then through the roof, but my question is: do I need to actually go through the roof? Could I instead have it go into the attic then 90 degree it out to the back, second floor wall? I can't find any particular code rules on if it has to penetrate the roof or not. This is a septic system, if that matters.   The reason for trying to avoid the roof is that I'd prefer to not climb up onto the roof...it's about 45 degrees and in the PNW so perpetually wet and mossy.


Dual-Boot Ubuntu 18.04/Windows 10 No Room

I am trying to dual boot my Dell Latitude D7270 with Windows and Ubuntu Desktop 18.04. When I enter I look at my storage in settings it says my C: drive has 98GB free (230 GB Total). Yet when I try to partition off the drive in Disk Management (right click on C:, click shrink volume) it only gives me the option to partition ~100MB (see attached image). What's wrong, why can't I partition off a reasonable amount of space?


public with sharing class TRAEstimateValidation {      public static List<CloudbyzITPM__Task_Resource_Assignment__c>   newTRAList = new List<CloudbyzITPM__Task_Resource_Assignment__c >();     //public static List<CloudbyzITPM__Task_Resource_Assignment__c>   oldTRAList = new List<CloudbyzITPM__Task_Resource_Assignment__c >();      public static void beforeInsertOperation(List<CloudbyzITPM__Task_Resource_Assignment__c>   newTRAList) {          Set<Id> taskIdSet = new Set<Id>();          for(CloudbyzITPM__Task_Resource_Assignment__c traRec : newTRAList) {             taskIdSet.add(traRec.CloudbyzITPM__Task__c);         }          if(taskIdSet.size() > 0) {             //system.debug('In Task:'+taskIdSet);             Decimal totalEstimate = 0; // Total Estimate             List<CloudbyzITPM__Task__c> taskList = [select Id,CloudbyzITPM__Estimate__c, (select  Allocated_Hours__c from CloudbyzITPM__Task_Resource_Assignments__r )                                                      from CloudbyzITPM__Task__c where Id IN: taskIdSet];             for(CloudbyzITPM__Task__c taskRec : taskList) {                 //System.debug('task rec'+taskRec);                 for(CloudbyzITPM__Task_Resource_Assignment__c  traRec : taskRec.CloudbyzITPM__Task_Resource_Assignments__r) {                     totalEstimate += ((traRec.Allocated_Hours__c != null) ? traRec.Allocated_Hours__c : 0);                     //System.debug('Total Estimate:-' + totalEstimate);                     if(totalEstimate > taskRec.CloudbyzITPM__Estimate__c){                         System.debug('Task estimate' + taskRec.CloudbyzITPM__Estimate__c + ' ' + 'Total Estimate :-'+ totalEstimate );                         traRec.addError('Total Task Resource Assignments Allocation hours is greater than Task Estimate');                         System.debug('Before insert or update done');                      }                 }             }         }     } }   Trigger  trigger TRAEstimateValidation on CloudbyzITPM__Task_Resource_Assignment__c (before insert,before update) {     CloudbyzITPM__Task_Resource_Assignment__c tra = new CloudbyzITPM__Task_Resource_Assignment__c ();     if(Trigger.isBefore && (Trigger.isInsert)){         TRAEstimateValidation.beforeInsertOperation(Trigger.new);     }     if(trigger.isUpdate && trigger.isBefore) {         if(CheckRecursionforPM.runOnce()){             TRAEstimateValidation.beforeInsertOperation(Trigger.old);         }     }  }


How to figure out what causes random Windows hangs?

It has been 2 full days that my computer has random 1second hangs... Even the mouse won't move, sound hangs too while listening to music.  I have made absolutely no software changes, there may have been automatic updates. I have checked my process list, and the hangs happen even when resources taken are a lot lower than my normal activities. I have tried closing all the programs I could and it is still happening. A virus scan did not result in any positives, as usual.  What else did I forget to check?     As of today, the freezes and hangs are not happening anymore. The only   thing that happened is a GPU driver update that ran automatically   before I could find free time to dig deeper.


Let $f $ be $C^{\infty}$ with $f(x,0)=f(0,y)=0\in\mathbb R$. Show $f(x,y) = xyg(x,y)$ for $g\in C^\infty$

Let $f: \mathbb{R}^{2} \rightarrow \mathbb{R}$ of class $C^{\infty}$ with $f(x,0)=f(0,y)=0$ for all $x, y \in \mathbb{R}$. prove that there exists $g: \mathbb{R^2} \rightarrow \mathbb{R}$ of class $C^{\infty}$ such that $f(x,y)=xyg(x,y)$ for any $(x,y) \in \mathbb{R}^{2}$. Since $f$ is of class $C^{\infty}$ then all its derivatives are continuous. I don't know how to prove the existence of the function $g$


Why I can't access google products like google.com and youtube.com?

First youtube started not loading videos, then almost all google products had problem. I had 12.04 and 12.10 on Asus N56VM. There was that problem. Now I have 13.04 on same machine. It still is. I have chrome, chromium and firefox. There is no difference. İnternet is generally fine. The problem is only on google products.       Edit:    Changing DNS not worked. I tried lots of DNS servers. I tried with 3 different ISPs. It is not a Flash Player issue I think, because the problem is on all of Google services (Gmail, Calendar, Maps), not only YouTube. Tried disabling hardware acceleration option on Flash Player. The problem is temporary. Some times Google.com, Gmail or Youtube work, some times not. Thus so difficult to track the problem. These are some links related to my question. It is the same problem and no answer.             Edit 2: Question marked as duplicate. Okay, question is same (I noticed that when it marked, sorry). But the answer to that question is "change DNS" and I said it does not work for me.   Edit 3: I noticed that If I sing out from google account Youtube works well on all of my browsers(Chrome, Chromium, Firefox). I tried with different google accounts of mine on different browsers. Result is same. Finally I catch something to track this problem. If I'm signed in to google there is problem with google products.


Is it okay to use Data Explorer as a recruiting tool?

It occurred to me that the Data Explorer makes enough user information publicly available that it can be an effective recruiting tool. I.e. it is easy to get a list of users in a particular location, who use certain tags, etc. and list any information about themselves that they have made publicly available (website URL, about me, etc.).  However it's also possible to get a link to their StackOverflow/StackExchnage profiles via the User.Id field.  Is it okay to use the Data Explorer as a means of identifying people and then potentially contacting them (given that contacting a person will only be possible if they have made that information publicly available)?  NOTE  This is not a duplicate of . The change in terms of service discussed here mentions recruiting companies that sell lists of contactable users and potentially lying regarding the origin and contents of these lists.  I'm asking a separate question - i.e. currently StackOverflow data is accessible to anyone with some SQL skills and understanding of the platform. I'm specifically asking about the case of providing your own HR department with a list of contactable users stipulating that these were identified via the StackOverflow platform - i.e. stipulating that 'these are a bunch of developers who are likely worth trying to recruit based on the way that the StackExchange platform functions'.  From a developer's perspective, it would still be annoying.   So while SE user data is available, it currently requires some technical knowledge to use. If the same data was made more easily available to anyone non-technical users (i.e. a free online SE data explorer for example, along the lines of Tableau, and similar interfaces), the additional reach of the data could result in spam/etc. But providing an easier means of exploring data than currently exists doesn't seem like it would be outside terms of use


Prove that if $a \mid b$ then $\gcd(a,b) = |a|$

I am having trouble completing the proof if $a \mid b$ then $\gcd(a,b) = |a|$. My attempt: If $a\mid b$ there is a $k \in \mathbb{Z}$ such that $b = ak$. Let $d = \gcd(a,b)$. Then $d \mid a$ and $d\mid b$ so by hypothesis we have $d\mid a$ and $d\mid ak$. Hence, $d \leq \gcd(a,ak)$. We can easily see that the largest common denominator of $a$ and $ak$ is $|a|$, thus $d \leq\gcd(a,ak) = |a|$ so $\gcd(a,b) \leq |a|$. I am stuck and not sure how to show the reverse inequality $|a| \leq \gcd(a,b)$ to complete the proof.


Call Javascript function defined inside iframe

I want to call javascript function (on click()) which is inside Iframe  <a onclick="abc();" href=# >Call Function which is inside Iframe </a>  <iframe id=myFrame>    <script>      function abc(){          alert("I am inside Iframe");      }     </script> </iframe>   It will be better if there is solution in JQuery.  Thank you


Update made my network stop working and receiving internal error message

I was notified with a bunch of updates just half an hour ago, mostly security updates in nature. Without thinking much I authenticated the installation. It required me to reboot to apply the changes. After reboot I noticed that the network was not working. Please check the image below.    Also on restarting again I got a error message that Ubuntu has faced an internal error. Since my network is not working I couldn't send the crash report to Ubuntu. Please check the screenshot below.    I'm new to Ubuntu. Just a 1 week old user. I think if I can somehow revert back the Wi-Fi update, i.e., backport it may help to solve the situation. But I don't know how to or if that's the only solution. Please help me out.  Thanks!


How can I move the boot drive (ie the one with GRUB)?

I have two drives and I installed Ubuntu 17.10 while my Windows 7 drive was mounted. Therefore GRUB was accidentally installed to drive with windows 7. I've been using it for months and it's working ok, but how can I move GRUB to the drive where Ubuntu is installed?


How to disable auto-hide of URL address bar in Chrome browser

I want the address bar to be visible all the time and not only when I up scroll. How can I do this?


Find all functions $f: \Bbb{R} \to \Bbb{R} $ such that $f(f(x))=-x$

Find all functions  $f: \Bbb{R} \to \Bbb{R} $ such that $f(f(x)) = -x$.   I think this equation has no continuous solution, because no polynomial can be the solution and we know that every continuous function is the limit of a sequence of polynomials.


How to make rsync copy actual data instead of symlinks?

In the source directory I have some symbolic links. These links point to some paths and data is present in those paths also; but using rsync it is copying only the link files, not the data that is present in the path.  lrwxrwxrwx 1 lafter lafter   58 Sep 26 16:57 8770 -> ../../../../.sites_repository/brest/8770/3.2.08.05.b-b0001 lrwxrwxrwx 1 lafter lafter   59 Sep 26 16:57 bootdvd -> ../../../../.sites_repository/colombes/bootdvd/12.1.013.000   Any solutions?


Finite Boolean ring with $1 \neq 0$ is isomorphic to $\mathbb{Z}_2\times \mathbb{Z}_2 \times \dots \times \mathbb{Z}_2$

Let $R$ be a finite Boolean ring with $1 \neq 0$. Show that $R\cong \mathbb{Z}_2\times \mathbb{Z}_2 \times \dots \times \mathbb{Z}_2$.   This is exercise 2 on p267 in the book abstract algebra of Dummit and Foote. The author gives the hint to use that if $e$ is an idempotent of a ring $R$ with $1$, then  $$R \cong Re \times R(1-e)$$  where $Re$ is a ring with identity $e$ and $R(1-e)$ a ring with identity $1-e$.  My attempt:  If $R = \{0,1\}$, then $R \cong \mathbb{Z}_2$ is trivial.  Hence, we may assume that $\{0,1\}$ is properly contained in $R$. Thus,we can pick an element $x \notin\{0,1\}$. We obtain because every element in a Boolean ring is an idempotent:  $$R \cong Rx \times R(1-x)$$  $Rx$ is a ring with identity $x \neq 0$ and $R(1-x)$ is a ring with identity $1-x \neq 0$. Moreover, $Rx$ and $R(1-e)$ have cardinality strictly smaller than the cardinality of $R$. These rings are also Boolean. Induction yields the result. $\quad \square$  Is this correct?


Why is half of my Mac's storage full with "system" files?

What does this mean:    The "system" section is taking up 80 GB. Why is it taking up so much and is there any way I can reduce it?


What is the best way to reencode a video with Xvid? I used FFmpeg in the past (I havent tried using FFmpeg with Xvid however - does FFmpeg keep up with Xvid releases?).  With FFmpeg I either need to figure out the bitrate of the video then reencode it slightly below or I use -sameq (I think it's same quality), however - that produces a file thats bigger and not better then a slightly less bitrate file.  Whats a good way to reecode these videos? (By the way - they are all on my HD as FLV1)


Let $R$ be a ring with identity, let $n\in \mathbb N^*$, and let $S=M_n(R)$ be the ring of $n\times n$ matrices with entries in $R$. Let $J$ be an ideal of $S$. Prove that the ideal $K := \{a \in R \mid a$ is the $(1,1)$ entry of some element of $J\}$  coincides with the set of elements of $R$ that occur as entries of elements of $J$.  First, I need to show that $M_n(K)=J$. I see it is kind of ambiguous to show that for any $A \in J$, $A \in M_n(k).$ Also, if $B \in M_n(K)$ it has entries in $K$, but how can we know that this entries are the same entries for a matrix in $A \in J$. I would apprecitate any help with that.


Was my question closed because it should be a community wiki?

I asked a question on Stack Overflow, but it was closed because it is "subjective". Someone mentioned that not making it a community wiki could be the problem.  Should a subjective question be a community wiki?


Reading character by character with bash read

I've been trying to use bash to read a file character by character.  After much trial and error, I have discovered that this works:  exec 4<file.txt  declare -i n while read -r ch <&4;       n=0      while [ ! $n -eq ${#ch} ]            do  echo -n "${ch:$n:1}"                (( n++ ))           done      echo ""       done   I.e., I can read it line by line and then loop through each line char by char.  Before doing this, I had tried: exec 4<file.txt &&  while read -r -n1 ch <&4; do; echo -n "$ch";  done but it would skip all whitespaces in the file.  Could you please explain why? Is there a way to make the second strategy (i.e. reading char by char with bash's read) work?


How does a photon transform into two particles

In pair production how do we know the energy of the photon is transformed into the mass of the two particles? How do we know it’s not something else similar to the photoelectric effect, where the energy of the photon interacts with the atom knocking parts off? To be clear I am not disagreeing with experiment or saying there are no pair productions. I want to know how we know for sure the exact way these pairs are produced.


"Seemed connected" vs "Seemed to be connected."

Example:     From this angle the bridge looked just like a garden path—due to the   grass and flowers growing along it and that seemed (to be) connected   to the land ahead.   Should I use to be here? Why or why not?


I came across the following statement:  International law, after all, is a system of manners written large.  I'm a native English speaker and translator, and I'm having a hard time translating this statement because I'm not clear on what is meant by written large. I wouldn't even know how to paraphrase this. Please answer if you're sure of the answer - no guesses please.


How can I post a question with a long error message in it?

There are other questions that ask this but none of their answers have worked for me. I have a very long error message (well not so very long, 354 chars) and I'm trying to show it in a question I am trying to post. But no matter what I do I get the message telling me it is code and I ought to indent it by 4 chars or use ctrl/k.  Here is what I've tried:   surrounding it with <code> tags, including the comment tag above like this: <!-- language: lang-none --> using <pre><code> instead using just <pre> using back ticks (ctrl/k does the same thing, so does {})   Other people seem to be doing this okay. What am I missing?


How to downgrade iOS from 9.3.1 to 7.1 (default version)?

I wanna check how my application works for iOS 7.1. I have got an iPad mini 2. I know it has iOS factory 7.1 . But now it has 9.3.2 (the lates). Is it possible to reset iPad until the default iOS? How to do it?


Set the default permission when creating a file

When I create a file, the permission is 644 (user rw, group r, other r). How can I make the default file generated to have permission as 664?


What is the purpose of a microcontroller bootloader?

From my understanding, for a common microcontroller (e.g. AVR, PIC), there are generally two methods of programming its flash memory.   Using a programmer:  (or some variant?) Some form of a bootloader, to which an external device communicates, ultimately allowing the microcontroller to flash its own memory.   Certainly there must be a very good reason to use a bootloader, else its current widespread use would be very odd. I just haven't seemed to have fully grasped it yet.  Is it that a programmer is expensive? But then, there are . Is the cost of one extra IC enough to warrant the use of a bootloader? If I'm not mistaken, the latest Arduinos get rid of the FTDI chip altogether, replacing it with an ATmega processor that does the USB to serial interfacing. Surely it would be possible to integrate the programmer's function on this IC for instance?  Or take for example, the PIC microcontroller. There is something I've seen called the . If something like this, with virtually no active components, can program a PIC then,   Why use a bootloader at all? What is the purpose of the relatively much more complex  (aside from robustness)? Debugging capability?


Having trouble trying to load serialized object

I am trying to save and load a single Java object with serialization.  I managed to make it save it to a file and from the looks of it it contains the data correctly (I can "read" the file with a text editor and somewhat distinguish the contents of arrays and variables in there)  protected static void saveChat(Chats chat1) throws IOException {     try(FileOutputStream f = new FileOutputStream("data.txt");             ObjectOutput s = new ObjectOutputStream(f)) {             s.writeObject(chat1);         }  }   protected static void loadChat(Chats chat1) throws FileNotFoundException, IOException,                                                     ClassNotFoundException {     try(FileInputStream in = new FileInputStream("data.txt");             ObjectInputStream s = new ObjectInputStream(in)) {             chat1 = (Chats) s.readObject();     } }   The problem comes when I try to load the (apparently) saved object chat1 with loadChat, which doesn't seem to do anything and doesn't load/write any data. I am not sure if I am missing anything.


Short Story about Fog/Mist (Not Stephen King or John Carpenter)

Looking for a short story I read 10 years ago but which is significantly older than that.  It is similar to Stephen King's "The Mist"; in fact, I found it while looking into "The Mist".  But it is older.  A radio (or telegraph?) operator stationed on top of a skyscraper sees a mist or fog settle on his city.  Either the mist/fog or something in it is killing people (?, can't remember exactly what it is doing) and the operator can see it happening from above.  Again, not "The Mist" or "The Fog"; older than both.


Hint proving this $\sum_{k=0}^{n}\binom{2n}{k}k=n2^{2n-1}$

I need hint proving this $$\sum_{k=0}^{n}\binom{2n}{k}k=n2^{2n-1}$$


How to adapt this table to break across page boundaries?  Original question here:      \documentclass{article}     \usepackage{tabularx}     \usepackage{amsmath}     \usepackage[table]{xcolor}     \usepackage{tabularx, multirow, makecell, rotating} %     \usepackage{enumitem}          \begin{document}         \begin{center}     \bfseries \settowidth\rotheadsize{List of Abbreviation/accronym} \begin{tabularx}{\linewidth}{|c|>{\centering\arraybackslash}X|}     \hline \cellcolor{gray!30} Abbreviation & \cellcolor{gray!30} Explanation     \\     \hline \multirow[b]{2}{*}{USA}                & \cellcolor{blue!30}  United state of america  \rule[-1em]{0pt}{2.5em} \\     \cline{2-2} %   &  %   \rule[-1em]{0pt}{2.5em} \\ %    \cline{2-2}     &    \rule[-1em]{0pt}{2.5em} \\     \hline         \multirow[b]{2}{*}{NY}                &  \cellcolor{blue!30} New york   \rule[-1em]{0pt}{2.5em} \\     \cline{2-2} %   &  %   \rule[-1em]{0pt}{2.5em} \\ %    \cline{2-2}     &     \rule[-1em]{0pt}{2.5em} \\     \hline \end{tabularx}     \end{center}     \end{document}


What happens if you dump antimatter into a black hole?

Let's say you have a 10 solar mass BH and dump 10 solar masses of antimatter into the BH... What would happen?  Would I have a 20 solar mass BH? Would the BH explode  Do we even understand what would happen to antimatter in the BH?


Are controlled undead already counted in the CR of the caster?

So let's picture ourselves a pretty drow priestess of Lolth, CLR3 which would make her a CR4 creature.  Add to her entourage Cuddles, an Owlbear Skeleton, CR 2 according to the MM and "Useless lot", three former priestess apprentices, now  Drow skeletons (we'll use the HUMAN skeleton for ease of use) CR 1/3 each all controlled with rebuke.  should i consider it a CR 4 or up the gains for a CR 5-6 encounter?  if she also raised/created undead and controlled them (assuming she was of a higher level) prior to meeting the group, would THAT change the CR?  Bottom line question: Would a lonely cleric, a cleric of the same level with rebuked undead and a cleric of the same level with both rebuked and created undead have the same CR?


aliases not getting expanded when run through SSH

so I have a alias for hadoop which I defined in bash_aliases which bashrc touches upon I guess.  alias hadoop=/usr/local/hadoop-2.7.2/bin/hadoop   Now the alias works fine when I directly try to run it. But when I try this  ssh aditya@localhost hadoop   I get the following error message  bash: hadoop: command not found   I tried the following too  shopt -s expand_aliases   But that didn't work. Could anyone help me out.  Update:   question is different from mine, because the ssh command is not generated by me, so the solution to that question does not solve my question. The ssh command is generated and executed by a script inside a library I am using. I do not prefer to modify that script to change the command as I am not completely aware of how that script works.


Accidentally deleted python 3.5 from Ubuntu 16.04 - all my files went and I cannot reinstall python package

I apologise for any technical incorrectness, I am a complete beginner in bioinformatics with really limited linux knowledge. I have the following problem – accidentally deleted python3.5 from my vm Ubuntu 16.04. Upon doing that, all my files went with it and I knew something was very wrong. I know understand that python 2.7 and 3.5 are default for my Ubuntu version and it was a bad idea.   I currently have python 2.7 and 3.7 in urs/bin, python 3 in linuxbrew/bin. However, I cannot run any packages depending on python version =>3.5. I tried to fix this by running sudo apt-get install python3-all this returns too many errors etc because python3 depends on python 3.5 and vice versa, catch 22 situation. I spoke to a family friend who works in the area of computer science, but not with ubuntu, and he suggests to delete all versions of python 3 (3 and 3.7.7 in my case) and start new installs. The issue with that is, I have seen a post from someone who deleted python3 from Ubuntu () and they lost the dashboard, terminal and Unity. I am anxious to do that. In addition, I am not sure python 3.7 has installed fully with all dependencies.   What is the best way to approach this?   Thank you very much in advance.   EDIT: This is the output from sudo apt-get install python3-all and sudo apt-get install software-center as suggested solutions in .  Is it a good idea to run sudo apt-get remove python3 first followed by sudo apt-get install python3? I am so scared to do that in case I lose the terminal as in the previous post of the person who removed python3.


I did something mildly dumb and decided I'd finally try updating my old iPod Touch 5 to the latest version of iOS (9.3.5) from the iOS 7.1.2.   Unfortunately, while it meant that some of my apps worked better, it also introduced a good 10s input lag whenever I wanted to unlock the screen or change songs more than once. I tried using a backup from before the update, but for some reason it kept the iOS version at 9.3.5, so I tried downloading 8.4.1 and updating from that .ipsw file.   The update failed with an error 3194 (presumably, 8.4.1 has exited the "signing window" I saw mentioned when I was downloading the .ipsw and thus won't update properly), and now my iPod Touch is locked into recovery mode.   Is there a solution to circumvent the update verification, or otherwise restore my iPod to its former, functional state? Or am I doomed to either an unconscionable amount of lag or buying a more recent iPod?


Im going to China soon and want to bring my Xbox One. How will I connect it to the outlets there? Is there a way to connect it to the outlets there?


Prove that $7$ is a primitive root modulo $p=2^s+1$.

I need help with the following question:  If $1<s\in \mathbb N$ and $p=2^s+1$ is prime, so $7$ is a primitive root modulo $p$.  My thoughts: First I know: $\phi(p)=p-1=2^s$. So if $r$ is the order of $7$ modulo $p$ then $r | \phi (p)=2^s$ then $rc=2^s$ and I don't know how to continue. Thank in advance.


I want to do a self study algebra, but don't know what would be a good source to start with. I have a few in my mind:   Artin, Algebra Dummit & Foote, Abstract Algebra   Is there anyone who could compare books above? I am also open for any suggestions! Thanks a lot.


How does time look relatively in a gravity well?

Relativistically, when two frames, say A & B are moving apart inertially, then the clock of  B will look slow compared to that of A; and the same holds for the clock of A from B.  What does the comparable set up look like in a gravity well, with A at the bottom and B at the top?   My guess would be not, because the situation isn't symmetrical; whereas the SR setup is.  I'm not interested in a quantitative calculation; but simply whether they're slower or faster; and simply a confirmation or refutation of the guess.


Currently I have Ubuntu 14.04 LTS installed on my PC, but unfortunately there are some programs, which do not run on Ubuntu even with Wine and there are no good alternatives available.  Therefore I want to additionally install Windows now. This [ article and many others recommend to first install Windows and then Ubuntu, an option that I do not have unless I can somehow back-up and transfer this current system.  It speaks of some advantages to virtualizing the other OS, but due to lack of knowledge, I do not really know what that means and what would be the best option in my case.  I plan to use Ubuntu 95% of the time and Windows only for few programs, that don't run on Ubuntu.  What do you recommend and how do I go about it?  Best regards and thanks for any advice!  Markus


Why are lower focal length lenses wider?

Most of the wide angle lenses are lower focal length and the telephoto lenses are of longer focal length.  Can someone explain (scientifically) to me how shorter focal length of the lenses is help to get a wider angle.  I don't see any relationship between wideness and focal length. Why can't a  telephoto lens have a focal length of 24 mm.


Is blood necessary to perform the summoning jutsu?

I always thought that blood is necessary to perform the summoning jutsu. However, I saw the second Mizukage and Madara performing it while being , so is it really possible?


The fates of corporations in the Star Trek universe

As we learned in the responses to the question  ,  the Federation (and Earth in particular) enjoys a post-scarcity economy.  As part of this, humans living inside the borders of the Federation do not earn or use money.  Picard makes this quite clear in his speech to Lily in First Contact, for example.  My question is about the fate in the Star Trek universe of human corporations, industrial conglomerates, and other profit-driven enterprises that once existed on Earth.  Is there any evidence that these enterprises still exist in some way, shape, or form in the 22nd, 23rd, and 24th centuries?  If not, when and why did they disappear?  If they do exist, then do they "employ" individuals on a merit-based platform without paying them (much in the way that Starfleet does with its officers and enlisted personnel)?  One might guess that the Third World War in the 21st Century "reset" the economic playing field of Earth and perhaps put corporations into retirement.  In Star Trek (2009), however, we see a pristine Nokia phone / communicator in Jim Kirk's stepfather's car (although one might argue that the device may be from an earlier time but still functions, like the car itself).


Trying to center a div containing some text in a very simple website I'm doing. Managed to get in centered vertically but cannot get in centered horizontally:   #welcome-section{     border: 10px solid blue;/*temporary for control*/     display: block;     height: 100vh;/*U.S. 10 100% viewport height*/     width: 100vw;/*100% viewport width*/     background-color: red;     color: white; } .hellotext{     position: absolute;     top: 50%;     border: 10px solid pink; }

¡Hola! I'm Carlos

text text text

              I would want the h1 and h4 to be horizontally and vertically aligned, and ideally responsive, and always stay bang in the middle. Thanks in advanced!


Are there any solutions for the diophantine equation $x^2+y^2=n$ ?  For $n \in \mathbb{P} \wedge n \equiv1\pmod4$  solutions are widely known.  Can we generalize a bit?


I'm trying to use anydice to figure out the probabilities of the various values of 1d1000 rolled on 3d10.  I want to know stuff like "what's the chance of rolling 900 or higher?  How about 950 or higher?"  I'm not sure how to script anydice to give me this information if it's actually possible.  Thanks for the help and keep up the good work!


Group homomorphisms from $\mathbb{C}^\ast$ to $ \mathbb{Z}$

I want to find $Hom_{\mathtt{Grp}}(\mathbb{C}^\ast,\mathbb{Z})$, where $\mathbb{C}^\ast$ is the multiplicative group, and $\mathbb{Z}$ is additive. $\mathbb{C}$ is the additive group of complex numbers. We have the following map:   $\large{\mathbb{C} \xrightarrow{exp} \mathbb{C}^\ast \xrightarrow{?} \mathbb{Z}}$  where the fiber of $exp$ is $\mathbb{Z}$  And I don't know if this can help, any hint?


Suppose I have $6$ fair coins, all facing heads ups. For each turn I will flip each of the $6$ coins. If a coin lands tails up, I set it aside. The next turn I take the remaining coins facing heads up and repeat the process. Now I want to know what is the expected number of turns $T$ until I have exactly $6$ tails. I know $$P(T=1)=\frac{1}{2^6}$$ But how do I find $P(T=x)$ with $x\gt 1$? For $T=2$ it seems I should count the different ways this might happen i.e. $1$ tail on turn $1$, $5$ tails on turn $2$, etc. There are $5$ different ways, so is the probability $5/64$? That does not seem right to me. Any hint is appreciated.