Quotient group with normal subgroup dividing the order of another group

Let G be a group with subgroup H and let $\Omega$ be the set of right cosets of H in G.  Show that if G is a group with a subgroup of index n then G has a normal subgroup with index dividing n!  Attempt:  There are n-distinct right-cosets of H in G. These distinct right cosets are a collection in $\Omega.$  So $\left | \Omega \right |=n$  Also, by definition of the index of the subgroup H in G and using Lagrange's theorem  We get $\left | G:H \right |=\left | H \right | \mid \left | G \right |=n.$  Also, note that the order of the symmetric group of the finite set $\Omega$ of order n is $\left | Sym\left ( \Omega \right ) \right |=n!$ Note that $ker\left ( \varphi \right ) \triangleleft G$  At this point I am stuck. Looking at the solution, it mentioned that the index of the $ker\left ( \varphi \right )$ is $\left | \left ( G \right )\varphi \right |$ which I do not quite understand. Is this a consequence or some theorem or properties?  Could someone kindly explain? Thanks in advance.


On Mac, are there keyboard shortcuts to create a new Space? Or at least any way to automate this process with keyboard shortcuts?

I want to not have to use the mouse to create Spaces. I want to use the keyboard for that.


Prevent rejected editor from trying again

So, I just had these two edit reviews happen to me:       The first one was obviously correctly rejected, so the editor apparently attempted to edit it again just two minutes later, with pretty much the same content (except differnt formatting).  Now for some reason I can’t understand, this actually went through the review process. Although there were two rejects and two approves, the third approve actually completed the review and published the edit.  Now it’s already hard for me to grasp why one would accept that edit. But I somewhat see the missing context at fault here. Reviewers don’t see the question, the comments, or even who asked the question (in this case, I think it would be a lot easier to see that it’s an invalid edit if it was clear, that the editor was actually the one asking the original question).  But what puzzles me the most is that after the edit was uniformly rejected at first, another nearly identical edit was possible just two minutes later. I would like to see some threshold here that prevents rejected editors from trying again until they find reviewers who incorrectly let it through. Or at least some warning (especially for the one asking the question) that editing an answer like that might not be what they should do in this case.  What do you think?


How to export an environment variable from .sh file in zsh?

I have the following shell script  TEST=/foopath export TEST   It is in a file called test.sh and on which I ran chmod +x test.sh   When I run ./test.sh I expect that I can then execute echo $TEST and see the output /foopath but I see nothing.   What changes are needed to make the above script export the variable $TEST when I run ./test.sh. Is this a bash vs. zsh difference?


In chat, there have been several times that we have passed around links to Github repos, to access others' code and resources. Could theses be oneboxed, possibly just including the person's username, the repo title, and tpart of the gist?


How do I draw a coordinate system with grid lines and markings?

I wish to draw a coordinate system in LaTeX (using tikz) and I have not been able to find a good instruction. I know how to draw basic graphics, but surely there must be a better way, than to draw the axes manually? My goal is to have a coordinate system  with grid lines and markings on the axes.


Unbiased Estimator for a Uniform Variable Support

Let $ x_i $ be iid observations in a sample from a uniform distribution over $ \left[ 0, \theta \right] $.  Now I need to estimate $ \theta $ based on $N$ observations and I want the estimator to be unbiased.  I thought about simple estimator $ \hat{\theta} = \max \left( x_i \right) $.  Based on simulation it is not biased, yet I couldn't show it analytically.  Could anyone, please, show it is unbiased?  BTW, I could easily find another, easy to prove, unbiased estimator, $ \hat{\theta} = 2 \mathrm{mean} \left( {x}_{i} \right) $


Calling function of derived class in std::thread constructor end up calling function of base class

class Decoder    { public:     virtual void run() {}     //... }   Now, I have this derived class:  class NVDecoder : public Decoder { public:     void run();   which is defined as this in the NVDecoder.cpp file  void NVDecoder::run() { //... }   As the function void of Decoder is virtual, doing:  //Decoder decoder = new NVDecoder(); auto decoder = std::make_shared<NVDecoder>(NVDecoder::NALU,Decoder::H264); decoder->run();   should call the NVDecoder's run function, not the Decoder's one. However, when I start a thread for a generic Decoder object, I need to do like this:  auto decoderThread = std::make_shared<std::thread>(&Decoder::run, decoder);   This calls the Decoder's run function, not the NVDecoder's one. I guess it's because I pass &Decoder::run. How do I start a thread that uses the NVDecoder's run function without passing &NVDecoder::run?


When to admit that your target cannot be predicted?

Assume you have a dataset, say churn. You sit down, do the data cleaning, the data engineering etc. etc. Since you want to predict if a customer churns, you decide on a logistic regression as a benchmark and get around 0.5 accuracy (it's a balanced dataset). You try different other classifiers since there wasn't something in your data cleaning which suggested one particular model as ideal, and all of them is around 0.5 accuracy. You gather some more data, create some more features, do backward/forward feature elimination, PCA everything you can imagine, but your models just simply won't improve significantly. Have you ever concluded "there is simply no pattern; the target is pure random from person to person" or will you argue that there will always be some pattern somewhere you just haven't found yet?


Misplaced \noalign when everything seems fine

Working in overleaf, I get the error Misplaced \noalign but I can't seem to figure out why. Here's my code           \begin{table}[H]             \centering             \begin{tabular}{|c|c|c|} \cline{2-3}                  \multicolumn{1}{c|}{}   & \rowcolor{Gray} SEL0  & SEL1  \\ \hline                 \cellcolor{Gray} UART   & OFF                   & OFF   \\ \hline                 \cellcolor{Gray} SPI    & OFF                   & ON    \\ \hline                 \cellcolor{Gray} I2C    & ON                    & ON    \\ \hline             \end{tabular}             \caption{Communication module selection PN532 Breakout Board}             \label{table:comModulePn532}         \end{table}   The error comes from the line \multicolumn{1}{c|}{}   & \rowcolor{Gray} SEL0  & SEL1  \\ \hline


How to show $A$ and $P^{-1}BP$ have same minimal polynomial?

Let $A$ and $B$, be two $n\times n$ matrices such that $A=P^{-1}BP$   for some invertible matrix $P$. Show that both $A$ and $B$ have the   same minimal polynomial.   I'm not sure how to approach this. The only method I know to find minimal polynomial of a matrix is to estimate from its characteristic polynomial using the fact that characteristic polynomial and minimal polynomial must have same roots. Any hints/suggestions?


How to remove line segments from a polygon for borders on a map in QGIS?

I am making a figure of the northern Himalaya, and in it are India, China, and Pakistan. These countries have disputed borders so I want to display these borders like they are displayed on Google Maps with dashed lines. But I don't know how to do this?  I have three vectors:   Country borders (thick black) Regions borders (thin black) Disputed borders (red dashed)   As you can see in the image below, the red dashed line has black lines appearing under it. For where there is a red line, I want only the red dashed line appearing and not the black lines. Everywhere else the black lines are fine. I believe they are polygons so that makes it a bit harder.


How can I copy a directory recursively and filter filenames in Perl?

How do I copy a directory including sub directories excluding files or directories that match a certain regex on a Windows system?


At what temperature will the hydrogen molecules escape from earth's surface?

At what temperature will the hydrogen molecules escape from the earth's surface?


Do i need force myself to create 3-4-sided polygons like on 1st picture or i can make faces like on 2nd pic? Does it depend on future use of the model (CNC, animation etc).


Why is Swift giving me inaccurate floating point arithmetic results?

Swift floating point arithmetic seems broken compared to C (and therefore Objective-C).  Let's take a simple example. In C:  double output = 90/100.0; // Gives 0.9 float output = 90/100.0f; // Gives 0.9   In Swift:  var output = Double(90)/Double(100.0) // Gives 0.90000000000000002 var output = Float(90)/Float(100.0) // Gives 0.899999976   What's going on? Is this a bug or am I missing something?  EDIT:  #import <iostream>  int main() {     double inter = 90/100.0;     std::cout << inter << std::endl; // Outputs 0.9     return 0; }


"a 0.22 μm filter" vs. "an 0.22 μm filter"

Reading "0.22" as "o point two two" should make "an" correct. Reading "0.22" as "zero point two two" should make "a" correct.  Can the author decide? Are both correct or is only one of them correct?  Before posting this, I checked  and Google - but googling that proved difficult.


I'd like to show that $1+x^py^{1-p} \le (1+x)^p(1+y)^{1-p}$ for all $x,y \ge 0$ and $p \in [0,1]$. I started out by defining a function $f(x,y)=(1+x)^p(1+y)^{1-p}$ and checking for critical points, but there are none in the domain I'm interested in. I think I'm probably missing a slick application of Jensen's or Holder's inequalities, but so far a proof eludes me. Any suggestions would be appreciated.


How do I achieve soft, dreamy, old-like photos? (May be thru film) Here are some examples:         It seems like they all may be film photography? If so, how do you achieve outcomes like this through film? And if it also is attainable with digital, how can you do this as well?  Still learning with film/digital, but I mostly take interest in film. Any help would be greatly appreciated!


Prove that $~~a=b=c~~$ if  $\frac{a}{b}+\frac{b}{c}+\frac{c}{a}$ and $\frac{a}{c}+\frac{b}{a}+\frac{c}{b}$  are integers.  My first attempt was to add $~\frac{a}{b}+\frac{b}{c}+\frac{c}{a}$ and $~\frac{a}{c}+\frac{b}{a}+\frac{c}{b}$ together and I got that $\frac{(a+b)(b+c)(c+a)}{abc}$ is an integer. I was not able make any further progress from here. Then I tried by multiplying them both. I got $~\left(\frac{a}{b}+\frac{b}{c}+\frac{c}{a} \right) \left(\frac{a}{c}+\frac{b}{a}+\frac{c}{b}\right)=3+\frac{a^2}{bc}+\frac{bc}{a^2}+\frac{b^2}{ac}+\frac{ac}{b^2}+\frac{c^2}{ab}+\frac{ab}{c^2}$. I was able to prove $~\frac{a^2}{bc}+\frac{bc}{a^2}+\frac{b^2}{ac}+\frac{ac}{b^2}+\frac{c^2}{ab}+\frac{ab}{c^2}$ is a integer but still could not make any progress. Then I tried squaring $~\frac{a}{b}+\frac{b}{c}+\frac{c}{a}$. I got $~~\left(\frac{a}{b}+\frac{b}{c}+\frac{c}{a}\right)^2=\frac{a^2}{b^2}+\frac{b^2}{c^2}+\frac{c^2}{a^2}+2\left(\frac{a}{c}+\frac{b}{a}+\frac{c}{b}\right)$ . So I was able to prove $~\frac{a^2}{b^2}+\frac{b^2}{c^2}+\frac{c^2}{a^2} $ and $~\frac{a^2}{c^2}+\frac{b^2}{a^2}+\frac{c^2}{b^2}$ is an integer. Using the same method I proved $~\frac{a^{2^k}}{b^{2^k}}+\frac{b^{2^k}}{c^{2^k}}+\frac{c^{2^k}}{a^{2^k}} $ and $~\frac{a^{2^k}}{c^{2^k}}+\frac{b^{2^k}}{a^{2^k}}+\frac{c^{2^k}}{b^{2^k}}$ is an integer although it was of no use. I don't know how to proceed further. Any help would be appreciated.


In a ring with no zero-divisors, for $(m,n) =1$, $a^m = b^m$ and $a^n = b^n$ $\iff a =b$

Let $R$  be a ring with with no zero divisors. If $a, b \in R$ are such that $a^m = b^m$ and $a^n = b^n$, where $m$ and $n$ are relatively prime positive integers, then show that $a = b$.   My attempt: Let $m>n$. $\therefore a^na^{m-n}= b^nb^{m-n}$ or, $ a^{m-n} = b^{m-n}$. How do I proceed from here?


Where can I find resources on how to animate/morph simple masses for architects?

I enjoy explanations to Blender modelling on youtube, but as an Architect i want to explain concept like the 'big companies'with the big budgets...  I want to be able to communicate concepts through video and simple 'morphing' animations as masses change in shape. Blender seems to be the perfect tool.  Please could I ask you to help me find the right resources to be able to achieve animations like these from HOK, BIG & Diller Scofidio + Renfro - lots of firms are doing this:        I would really appreciate assistance if at all possible. If there are already tutorials on youtube, perhaps someone could point me to them.


I'm fairly new to linux but I want to install it on my chromebook with crouton. Is there a way to install something like lubuntu or xubuntu without any of the software normally bundled? For example, I don't need a music manager, libre office, an internet browser (I will install chrome). I would rather just choose these kinds of programs myself and install what I need rather than have them included. Is this possible?


invalid use of template-name ‘Set’ without an argument list - Header and cpp files

I'm having a lot of problems converting my Set class into a template class. I have commented out all of the code other than the constructors and cannot get it to work. I have a header file and cpp file. Any advice?  I used the solutions from the other thread, but am unable to make it work.  Note: I only included the constructors from my cpp file since I'm working on that first.   Header file:  #ifndef SET_H #define SET_H #include <iostream> using namespace std;  template <class T> class Set {     //friend istream& operator>>( istream& in, Set& set );     //friend ostream& operator<<( ostream& out, Set& set );      public:             /*bool operator+( const T& rhs );             Set operator+( const Set& rhs );             bool operator-( const T& rhs );             Set operator-( Set& rhs );             Set operator^( Set& rhs );             bool operator==( Set& rhs );             bool operator!=( Set& rhs ); */             Set();             Set( T2 [], int, char );             Set( const Set& );             /*~Set() {                     delete elements;                     elements = NULL;                     numElements = pSize = 0;             }             int length() const;             T getElement( int ) const;             void display();             void checkUp();             bool add( T );             bool contains( T );             bool remove( T );             int findCell( int, T );             */     private:             static const int DEFAULT_SIZE = 5;             static const int emptyCell = -99999;             char name;             int pSize, numElements;             int *elements;  };   cpp File:  #include "set.h"  template < typename T >  template <class T2> Set::Set() {     elements = NULL;     pSize = numElements = 0; }  template <class T2> Set::Set( T2 array[], int ps, char nm ) {     elements = NULL;     pSize = numElements = 0;      //For each member of array, we're going to add it to this     /*     for ( int i = 0; i < ps; i++ )             this->add( array[ i ] );     name = nm;     */ }  template <class T2> Set::Set( const Set& s ) {     elements = NULL;     pSize = numElements = 0;      /*For each member of the passed set, we're going to add to this     for ( int i = 0; i < s.length(); i++ )             this->add( s.getElement( i ) );     */ }   Thanks!!


The question is: If the number of Sylow $p$ groups is not congruent to $1 \pmod{p^{2}}$, then there exists two distinct Sylow $p$ subgroups $P,Q$ such that $[P : P\cap Q] = [Q : P\cap Q] = p$. I know that whenever $PQ$ is a group, $|PQ| = \frac{|P||Q|}{|P \cap Q| }$ and that there are $1+kp : 1 \leq k \leq p-1$ possible Sylow $P$ subgroups, but I do not know how to proceed.


Are Complex Substitutions Legal in Integration?

This question has been irritating me for awhile so I thought I'd ask here.  Are complex substitutions in integration okay?  Can the following substitution used to evaluate the Fresnel integrals:  $$\int_{0}^{\infty} \sin x^2\, dx=\operatorname {Im}\left( \int_0^\infty\cos x^2\, dx + i\int_0^\infty\sin x^2\, dx\right)=\operatorname {Im}\left(\int_0^\infty \exp(ix^2)\, dx\right)$$  Letting $ix^2=-z^2 \implies x=\pm\sqrt{iz^2}=\pm \sqrt{i}z \implies z=\pm \sqrt{-i} x \implies dx = \pm\sqrt{i}\, dz$  Thus the integral becomes  $$\operatorname {Im}\left(\pm \sqrt{i}\int_0^{\pm\sqrt{-i}\infty} \exp(z^2)\, dz\right)$$  This step requires some justification, and I am hoping someone can help me justify this step as well: $$\pm \sqrt{i}\int_0^{\pm\sqrt{-i}\infty} \exp(z^2)\, dz=\pm\sqrt{i}\int^\infty_0\exp(z^2)\, dz=\pm\sqrt{i}\left(\frac{\sqrt{\pi}}{2}\right)$$  Thus  $$\operatorname {Im}\left(\int_0^\infty \exp(ix^2)\, dx\right)=\operatorname {Im}\left(\pm\frac{\sqrt{i\pi}}{2}\right)=\operatorname {Im}\left(\pm\frac{(1+i)\sqrt{\pi}}{2\sqrt{2}}\right)=\pm\frac{1}{2}\sqrt{\frac{\pi}{2}}$$  We find that the correct answer is the positive part (simply prove the integral is positive, perhaps by showing the integral can be written as an alternating sum of integrals).  Can someone help justify this substitution?  Is this legal?


RecognitionListener gives NullpointerException with Viewholder

I am making a listview with multiple sppech_recognizers inside its each row... in which that speech recognition result text will be stored inside the textview inside the listview:  Basic Model:  ListView -> { rows :: [ multiple speech recognizers ] }   public class ListAdapter extends ArrayAdapter<datamodel> implements RecognitionListener {   public static class ViewHolderItems {     AtomPayment datamodel;     TextView total_hrs;     TextView date;     TextView Hour;     TextView value;     ToggleButton mic_for_hrs;     ToggleButton mic_for_desc; }  @Override public View getView(int position, View convertView, ViewGroup parent) {     row = convertView;     ViewHolderItems holder = null;      if (row == null) {         LayoutInflater inflater = ((Activity) context).getLayoutInflater();         row = inflater.inflate(R.layout.list_row_addtime, parent, false);          holder = new ViewHolderItems();         holder.atomPayment = items.get(position);         holder.mic_for_hrs = (ToggleButton) row.findViewById(R.id.MIC_hours);         holder.mic_for_hrs.setTag(holder.atomPayment);         speak_hours(holder, position);         holder.mic_for_desc = (ToggleButton) row.findViewById(R.id.MIC_desc);         holder.mic_for_desc.setTag(holder.atomPayment);          holder.date = (TextView) row.findViewById(R.id.textview_date);         setDateTextChangeListener(holder);         holder.Hour = (EditText) row.findViewById(R.id.edit_hours_data);         setHourTextChangeListener(holder);         holder.value = (EditText) row.findViewById(R.id.edit_desc_data);         setValueTextListeners(holder);      } else {         holder = (ViewHolderItems) row.getTag();     }         row.setTag(holder);        return row; }  @Override public void onResults(Bundle results) { Log.i(LOG_TAG, "onResults 1");         String text = "";         Float valueof_text;         Integer compare = 24;          try {             ArrayList<String> matches = results.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);             text += matches.get(0);              System.out.println("MAIN----------------->      " + matches);             System.out.println("TAG----------------->      " + matches.get(0));              valueof_text = Float.parseFloat(text);              if (valueof_text.intValue() > compare.intValue()) {                 Toast.makeText(context, "Speak Again!!!", Toast.LENGTH_LONG).show();             }             else {                 holder.Hour.setText(text);             }          } catch (NumberFormatException number){             number.getMessage(); number.printStackTrace();         }  catch (NullPointerException number){             number.getMessage(); number.printStackTrace();         } }   And from this i am getting this below result for this multiple sppech recognizer issue:  java.lang.NullPointerException at com.example.testing.ListAdapter.onResults(ListAdapter.java:429) at android.speech.SpeechRecognizer$InternalListener$1.handleMessage(SpeechRecognizer.java:448) at android.os.Handler.dispatchMessage(Handler.java:110)   I have get stucked here, any help would be completely appriciated... Thankyou in advance.


Multiple regression in R results different to simple linear regression?

Hi I am having trouble acquiring the final results for presentation.  The results from a multiple regression are different to my results in a simple linear regression.   For example, the multiple regression model mul <- lm(Response ~ Temp + Wave + Overcast, data = env) gives me a p-value for 'Temp' of $0.01$, while the others are $>0.05$.  However, a simple linear regression sim <- lm(Response ~ Temp, data =env) returns a p-value for 'Temp' of $0.03$.  Which result should I be presenting, and also how to I interpret the relationship between the predictors in the multiple regression?


Transfer from regular savings to NRO account

I have a regular savings account in India and a NRE/NRO account as well with a different bank. I just haven't gotten around converting my regular savings to NRE/NRO. Can I move my funds from regular savings to NRO?


Parsing wmic logicaldisk get Information

I am retrieving disk information via JavaScript with the wmic statement, wmic logicaldisk get freespace,name,size,volumename, which produces the following output, but in a single string.  "FreeSpace      Name  Size           VolumeName  " "560232755200   C:    999526756352   System      " "999369699328   D:    999558213632   SSD         " "1511570386944  E:    8001545039872  Get         " "4620751712256  F:    8001545039872  BR          " "788449492992   G:    4000650883072  Seen        " "2296009408512  H:    4000768323584  Seen 2      " "3594248679424  I:    8001545039872  2160        " "3507750227968  J:    8001545039872  1080        " "945300619264   K:    999625322496   Trailers    "   I parse the above output with the following JavaScript.  window.onload = function(){   const cp = require('child_process')   let drives   cp.exec('wmic logicaldisk get freespace,name,size,volumename', (error, stdout)=>{     drives = stdout.trim().split('\r\r\n')       .map(value => value.trim().split(/\s{2,0}/))       .slice(1)   }) }   That JavaScript already produces my desired output. It produces an array of nested arrays. Each row of information in the command prompt output corresponds to a nested array. Each nested array has four values that correspond to the originally queried data points.  [   ["560232439808",  "C:", "999526756352",  "System"  ]   ["999369699328",  "D:", "999558213632",  "SSD"     ]   ["1511570386944", "E:", "8001545039872", "Get"     ]   ["4620751712256", "F:", "8001545039872", "BR"      ]   ["788449492992",  "G:", "4000650883072", "Seen"    ]   ["2296009408512", "H:", "4000768323584", "Seen 2"  ]   ["3594248679424", "I:", "8001545039872", "2160"    ]   ["3507750227968", "J:", "8001545039872", "1080"    ]   ["945300619264",  "K:", "999625322496",  "Trailer" ] ]   I am wondering whether or not there is a way to similarly parse the information, but with command prompt instead?


Why does this markdown preview differently?

See . When published, the markdown does not render the same way it does in preview for edit mode. The numbered list does not continue when published, but appears to continue in preview. Moreover, the OP actually typed 2, but it still rendered as 1 which is puzzling.    Published        Editor Preview


I'm trying to create a blackjack program for school and I don't understand why my program keeps starting over after i ask for another card once I get my first two cards. Any help would be great. My code for everything is below.  import java.util.Scanner; import java.util.*;  public class BlackjackGame {      public static void main(String[] args) {          String anotherCard, playAgain = "y", ctn;         int nextCard, card1, card2, dCard1, dCard2;         int cardTotal = 0, dTotal = 0;          Scanner keyboard = new Scanner(System.in);          Random random = new Random();          // Begin dealing the players first two cards          while (playAgain == "y")         {             //dealers first two random cards             dCard1 = random.nextInt(10) + 1;             dCard2 = random.nextInt(10) +1;              //players first two random cards and card total             card1 = random.nextInt(10) + 1;             card2 = random.nextInt(10) + 1;             cardTotal = card1 + card2;              //Dealers two card total and display only one dealer card             dTotal = dCard1 + dCard2;             System.out.println("Dealer shows: " + dCard1);              //Display players first two cards & card total             System.out.println("First Cards: " + card1 + ", " +card2);             System.out.println("Total: "+ cardTotal);              System.out.print("Another Card (y/n)?: ");             anotherCard = keyboard.nextLine();              while (anotherCard == "y")             {                 nextCard = random.nextInt(10) + 1;                 cardTotal += nextCard;                 System.out.println("Card: " + nextCard);                 System.out.println("Total: " + cardTotal);                  if (cardTotal > 21)                 {                 System.out.println("You busted, Dealer Wins");                 System.out.println("Do you want to play again? (y/n): ");                 playAgain = keyboard.nextLine();                 }                    if (cardTotal < 21)                  System.out.print("Another Card (y/n)?: ");                 anotherCard = keyboard.nextLine();                 if (anotherCard == "n")                 System.out.print("Press c to continue dealers cards");                 ctn = keyboard.nextLine();                   while (ctn == "c" && dTotal < 17)                 {                     nextCard = random.nextInt(10) + 1;                     dTotal += nextCard;                      if (dTotal > 21)                     {                     System.out.println("Dealer Busts, You Win!");                     System.out.println("Play Again? (y/n): ");                     playAgain = keyboard.nextLine();                     if (playAgain.equalsIgnoreCase("y"))                             playAgain = "y";                         else                             System.exit(0);                     }                  }              }          }     } }


How do I temporarily disable applications from starting up at login?

Is there any way to temporarily disable applications from starting up at login? I'm referring to both Lion apps that are started due to the resume/reopen feature, and also to applications set to launch in the Login Items setting.  I know that I can disable the apps from launching in Lion by unchecking the relevant checkbox right before I shut down, but what if I forget to do this, or if I decide I don't want them to start up right before I login?  To clarify: I'm looking for a one-time, temporary solution rather than something that will disable them all the time.


Do Doctor Who and Star Trek occur in the same universe?

In a  the Doctor has, in his fourth and eleventh incarnations landed on the Enterprise. Regardless of whether Kirk or Picard he has entered the trek universe but in "The Impossible Astronaut" an elderly woman asks a member of The Silence if his costume is from the Star Trek show.  My question is, can the Star Trek universe and 'Whoniverse' coincide with each other? Also if they can be linked together could the aliens from Star Trek appear on Doctor Who?  I feel as though mixing them would give a larger audience to both shows. Would there be as many legal complications in using the aliens like romulins, volcan, borgs etc... in Doctor who?


When we light a candle or kerosene lamp, why fire is turning to a drop shape?

I am curious to know about this phenomena.


The use of hyphen in "twentieth-first-century reader" and "twentieth-first century reader"

Which variant is correct: "twentieth-first-century reader" or "twentieth-first century reader"? Is the use of the second hyphen in the first example a matter of taste or not?


I've noticed that some people use words or phrases like can, could, seems like, it's likely, some people think, etc when they're talking and this makes it harder dispute what they're saying or arguing. In a way, they're much less likely to be wrong since they're not committing that much to what they're saying. I was wondering if there is word to describe this behavior.   For example, let's say you believe in some statement A. Instead of saying "A is true", you say "A is very likely to be true". This way, if someone says "A is not true because X, Y, Z" you can say "I didn't say it was true, I said it is very likely to be true. Therefore I wasn't wrong". This way you can get the same point across and not risk being wrong.


G-streamer, what is it?  How can I determine if it is already installed?  I've already looked in the obvious places - where and how do I get it?


So i wanna print this code.. it says:     non - static method rain cannot be accessed from a static context.   the question is to print the names of all the months and their rainfall in parallel columns and their total average and the month with highest and lowest rainfall. Please help me out.   public class rainfall  {      String[] rain =  { "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec" };     double[] values = { 0.40,0.94,3.21,3.74,1.73,1.03,1.27,2.58,6.98,6.90,2.80,2.53};       public double Total( double total )     {         total = 0;          for( int i = 0 ; i < values.length ; i ++ )         {             total += values[i];         }          return total;     }      public double Average( double average)     {         double total = 0;         Total (total);         for ( int j = 0; j < values.length; j ++ )         {             average = total/values.length ;         }          return average;     }      public String mostRain (double high,String highest )     {         high = values[0];          for(int i = 1 ; i < rain.length ; i ++ )         {             if ( values[i]>high )             {                 highest = rain[i];             }             return highest;          }     }      public String leastRain ( String least, double low )     {         least = "";         low= values[0];          for(int i = 1; i < rain.length ; i++ )         {             if ( values[i]<low )             {                 least = rain[i];             }              return least;         }     }      public static void main(String[]Args)     {         String highest = "" ;         String least = "";         double total = 0 ;         double average = 0 ;         double high = 0;         double low = 0;            System.out.println(" AUSTIN Tx RAINFALL 2009 " );          for( int i = 0 ;  i < rain.length ; i ++ )         {             System.out.println(rain[i]+"\t"+values[i]);         }          System.out.println(Total(total));         System.out.println(Average(average));         System.out.println(mostRain(highest,high));         System.out.println(leastRain(least,low));      } }


Effect of each parameter on a Monte Carlo Simulation

I was wondering what is the best way to determine the effect of each random parameter on the result obtained from a Monte Carlo Simulation.  I realise I have asked a similar question , but this time I am making this question in a more general manner as I didn't get any answers previously.   Background: I'm essentially running a Monte Carlo Simulation where I sample randomly from 65 Normal Distributions and 2 Uniform Distributions. Then, i then input these values to a linear equation and run this for 500.000 iterations. I just wanted to determine the best way to establish the relative effect of each of these 67 (in total) random variables on the final outcome from my Monte Carlo Simulation.


I agree that without extending class B  the output is "1233" but why if extending class B with A the code doesn't compile ?   public class SomeClass {      public static class A {          public void f(int x){             System.out.print("1");         }          public void f(Object x){             System.out.print("2");         }     }      public static class B // extends A {          public <T> void f(T x){              System.out.print("3");         }     }      public static void main( String[] args){         A a=new A();         B b=new B();         a.f(3);         a.f("hello");         b.f(3);         b.f("hello");     } }


The Rutherford experiment proved that the Thomson model was incorrect and the Rutherford model was the right one, this because the $\alpha$ particles were deflected by the nucleus and in the Thomson model this was not possible. The question is: since in the Thomson model we have the electrons, which have negative charge, why an $\alpha$ particle shouldn't be deflected? I know that the total charge in Thomson model is $0$ so there is no Coulomb interaction, but $\alpha$ particles maybe could touch the electrons and like a classical collision change their trajectory. Is it possible that $\alpha$ particles and electrons touch each other and change their trajectories not only beacuse of Coulomb interaction but also beacuse they "touch", like a neutron against another neutron? All this not considering MQ which did not exist at the time of Rutherford experiment, so particles were just particles and not waves.


Earlier today I thought I proved that the following series diverged:  $$\sum_{n=2}^\infty\frac{\phi(n)}{n^2}$$  as a result of a misapplication of the prime number theorem. I mistook $\phi(n)$ for $\pi(n)$ in the statement. Is this salvageable? I've been trying to find lower bounds for $\phi(n)$ that I may pass to, but the literature on this is a bit dense for me.  Thanks


Galois Groups are isomorphic to subgroups of symmetric groups.

I am currently working through Joseph Rotman's book "Galois Theory" and am trying to prove the following theorem.  If $f(x) \in F[x]$ has $n$ distinct roots in its splitting field $E$, then $\operatorname{Gal}(E/F)$ is isomorphic to a subgroup of the symmetric group $S_n$, thus its order is a divisor of $n!$.  I have struggled to understand the proof in the book and have therefore tried to write my own proof of this fact, I have found some questions close to this on this site, but haven't been able to find exactly what I'm looking for. My proof (so far) is as follows: Proof: Let $X = \{\alpha_1, ... , \alpha_n \}$ be the set of roots of $f(x)$, as $E$ is the splitting field of $f$, it may be written as $E = F(\alpha_1, ... , \alpha_n)$ and noting that $\alpha_i \neq \alpha_j$ for $i\neq j$. Let $\sigma \in \operatorname{Gal}(E/F)$ then $\sigma(X) = X$ (a result from an earlier lemma). Now I would like to construct an injective homomorphism from $\operatorname{Gal}(E/F)$ to $S_n$, my guess is the map which sends $\sigma$ to its restriction in $X$, which I shall denote by $\sigma_X$. Let $g$ be this map, then it is clear that $g$ is a homomorphism. Now I try to show that $g$ is injective, consider $\sigma, \phi \in \operatorname{Gal}(E/F)$ where $\sigma \neq \phi$, both of these functions are F-automorphisms of $E/F$, so they "fix" $F$, then we can conclude that $\sigma$ and $\phi$ can be different if and only if they act differently on $X$, which in the language of mathematics is precisely $\sigma \neq \phi \Leftrightarrow \sigma_X \neq \phi_X$. This is the definition of an injective function. This means that $\left|\operatorname{Gal}(E/F)\right| \leq |S_n| = n!$, however due to having constructed a homomorphism, we have mapped a group  to another group, hence we have mapped $\operatorname{Gal}(E/F)$ to a subgroup of $S_n$, whose order divides $|S_n|$ and therefore $\left|\operatorname{Gal}(E/F)\right|$ divides $n!$, completing the proof. Question I am wondering whether my proof for this is correct, I think that it is mostly there, with the statement  we can conclude that $\sigma$ and $\phi$ can be different if and only if they act differently on X  perhaps being the only issue.


MInecraft Adventure mode protection within a survival mode

I am setting protection in factions on my command block server using adventure mode. I have a command block setting mode to survival in a certain radius, but within that radius I want a smaller radius set to adventure mode. Is there a way to set what's not in the radius of adventure mode to survival mode?


Replicate data from one list to another list sharepoint

I have a list A with columns Emp ID, First name & last name and list B wih column name Emp ID, First name, last name , phone number and address.  I want functionality such that when i enter item in List A and save same data should get copied in 3 columns of list B. Can someone help me with the approach. Thnks


Finding first and last index of some value in a list in Python

Is there any built-in methods that are part of lists that would give me the first and last index of some value, like:  verts.IndexOf(12.345) verts.LastIndexOf(12.345)


I'm traveling to London, UK for tourism. I just received my passport from UK embassy with 6 months visa. My passport is about to expire and will renew it before travelling to London. So I'm travelling with 2 passports (one with the visa and one is new), I believe that's fine with the UK immigration. My concern is that the visa has the passport number and never travelled to uk before, is there any problem travelling with passport has new visa and holding another new passport?  (Note: travelling from Saudi Arabia to UK)


Improper display of parentheses in fraction of fraction

The following code:  $\dfrac{\left( \dfrac{\left( \dfrac{1}{2}\right) }{2}\right) }{2}$   gives a nasty output:   It seems that the $\left( \right)$ command doesn't do the job.  Any idea how to solve this in general?


Failed to open a session for the virtual machine on genymotion

When I run genymotion, I got this error in the following screenshot:


Create points inside polygon based on attribute in QGIS

I have a polygon layer with population and I need to create a new point layer based on that polygon layer.  The polygon layer has an attribute with the specific number of people living in each polygon.   How do I create X points (where X is the absolute number of people based on the attribute information) inside the boundaries of each polygon?


error: file '/grub/i386-pc/normal.mod' not found. grub rescue>   What can I do? I just sit and stare at it.   I found my old netbook (Dell Inspiron 1010) which I have not used for about four years. I replaced Windows XP with Ubuntu 12.10. I used my bootable USB drive. I installed and rebooted. I got the message that normal.mod is not found.   What should I do? Type exit, reboot, or quit? Should I re-install?


Let n be a positive integer and let G be an Abelian group. Define  $H := \{x ∈ G : |x| \ \text{divides} \ n\}$  where x denotes the order of |x|.  Show that H is a subgroup of G.  I know I need to prove that H is non-empty, contains the identity, e, and that it contains $ab^{-1}$.  I'm just not sure how to prove this, thank you for any help!


Postfix can't send email reporting mail "Exceeded Mail Size Limit"

The errors:  Nov 30 04:58:26 serverm postfix/anvil[32747]: statistics: max connection rate 1/60s for (smtp:*.*.*.*) at Nov 30 04:48:26  Nov 30 04:58:26 serverm postfix/anvil[32747]: statistics: max connection count 1 for (smtp:*.*.*.*) at Nov 30 04:48:26  Nov 30 04:58:26 serverm postfix/anvil[32747]: statistics: max cache size 2 at Nov 30 04:53:26   The attachment size is 75 MB. Any idea ?


Say $1 = g^2$ is a Group, so $p\cdot p = 1,$ prove that that the group is commutative?

I know a good proof, but i want to proof it in my way, im asking if its right. Say $1 = g^2$ is a Group, so $p\cdot p = 1$ with $p$ element of $P,$ prove that that the group is commutative?   $1 = e,$ the neutral element. $1.$ so we know for every group exist associativity. $e = g\cdot g,$ from that we can conclude that every is the inverse element of itself.   i proof that $(g\cdot a) = (a\cdot g)$  $g\cdot a$ is also inverse to itself, so $(e\cdot g)\cdot(e\cdot g) = e.$ now the rest.  $$(g\cdot a)^2 \cdot (a\cdot g)^2 = e $$ $$(g\cdot a) \cdot(g\cdot a)\cdot (a\cdot g)\cdot(a\cdot g)=e$$  because of associativity $$(g\cdot a)\cdot g \cdot(a\cdot a)\cdot g)\cdot(a\cdot g)=e$$ $$g\cdot(a\cdot g)\cdot (g\cdot a)\cdot g=e$$ because of associativity i can also start with $(a\cdot g)$ and $(g\cdot a)$ and for that its only true if they are the inverse off another thus the same.


Blender inbuilt render engine black spots

I started using blender for render a little time ago and today i'm experimenting this odd black spots/dots/zones issue when rendering with blender own render engine but not with the cycles one as you can see on the image attached. Can you help me?


I'm a newbie when it comes to spring so this maybe something simply I'm over looking but I've been trying for hours to no avail. I have spring and hibernate integrated and working however, I want to log the queries to a file so that I can examine them. I'm using log4j for the logging but the issue is I can't get hibernate to write to the file and was hoping to get some clarification.   Here is the sessionFactory bean in applicationContext  <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">     <property name="dataSource" ref="dataSource" />     <property name="hibernateProperties">         <props>             <prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>             <prop key="hibernate.show_sql">true</prop>             <prop key="hibernate.format_sql">true</prop>         </props>     </property>     <property name="packagesToScan" value="com.example"/> </bean>   Log4j configuration  <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="false">  <appender name="FILE" class="org.apache.log4j.RollingFileAppender">     <param name="File" value="${catalina.home}/logs/my-log-file.log" />     <param name="Append" value="true" />     <param name="MaxFileSize" value="20MB" />     <param name="MaxBackupIndex" value="2" />      <layout class="org.apache.log4j.PatternLayout">         <param name="ConversionPattern" value="%d{DATE} %c | %msg %n" />     </layout> </appender>  <appender name="hibernate-rolling" class="org.apache.log4j.RollingFileAppender">     <param name="File" value="${catalina.home}/logs/hib-example-file.log" />     <param name="Append" value="true" />     <param name="ImmediateFlush" value="true" />     <param name="MaxFileSize" value="20MB" />     <param name="MaxBackupIndex" value="2" />      <layout class="org.apache.log4j.PatternLayout">         <param name="ConversionPattern" value="%d{DATE} %c | %msg %n"/>      </layout> </appender>   <logger name="org.hibernate.SQL" additivity="false">     <level value="debug" />     <appender-ref ref="hibernate-rolling" />  </logger>   <root>     <priority value="INFO"></priority>     <appender-ref ref="FILE" /> </root> </log4j:configuration>   Any help is much appreciated?   EDIT:  I have tried the loggers that were provided in that  but that did not cause the queries to be written to the file.


Do I get latest possible update now for obsolete Windows

Now, when Windows 7 support has discontinued, if I install brand new Windows 7 on my machine (my laptop has possibility to make a factory reset), will it still get all updates automatically from the point it was launched up to 2020 Jan. 14? Do the same rules apply for Windows 8? Is there a way to download and install all of these updates manually if automatic update fails?


How to fix Null Pointer Exception from Comparable interface in Binary Search Tree

In my program for a binary search tree, I am getting an error after adding an object to the tree in my main method. It is resulting in a Null Pointer exception from my Comparable implementation. My program places morse code characters in a binary search tree, so I am trying to compare objects lexicographically by their code values. Why isn't this working?  public class MorseCharacter implements Comparable<MorseCharacter> {  private String code; private char letter;      public int compareTo(MorseCharacter morseCharacter) {      String code1 = this.code;     String code2 = morseCharacter.getCode();      return code1.compareTo(code2); }      public int hashCode() {     int hashVal = 0;      for (int i=0; i<code.length();i++) {         hashVal = (hashVal*31 +code.charAt(i));     }      return hashVal; }  public boolean equals(Object obj) {     if (this == obj) {         return true;     }      if (obj == null) {         return false;     }      else {         return (this.hashCode() == obj.hashCode());         }     }   Here is the section in main method. I am parsing data from a file, I have checked and it reads this correctly.           try {         reader = new BufferedReader(new FileReader(file));         String line = reader.readLine();           while (line != null) {              String[] output = line.split(" ");             String letter = output[0];             MorseCharacter morseCharacter = new MorseCharacter(letter.charAt(0), output[1]);             BSTElement<String, MorseCharacter> bstElement = new BSTElement(letter, morseCharacter);             tree.add(bstElement);             line = reader.readLine();         }         reader.close();   Here is the error message:  Exception in thread "main" java.lang.NullPointerException: The object you are comparing to is null. at bridges.base.Element.compareTo(Element.java:207) at MorseCodeTree.add(MorseCodeTree.java:86) at MorseCodeTree.main(MorseCodeTree.java:220)   Changes to compareTo method (did not fix):  public int compareTo(MorseCharacter morseCharacter) {      if (this.code == null) {         return 0;      }      return this.code.compareTo(morseCharacter.getCode()); }


Etiquette for duplicate, yet unanswered questions

I've seen before where some questions get closed as duplicates of unanswered(or even closed) questions. Is this behavior that should be encouraged?  For instance, there has been a few times where I was going to ask a question and found a similar question beforehand. The similar question had no good answers for me, but I didn't create a new question because I knew it'd get closed as a duplicate. Even if my question was more specific, it was still related enough to be considered a duplicate(even though mine may be more easy to answer due to additional info.)  What do you think? Should asking unanswered questions be OK and not closed as duplicates? Or should we encourage bumping the unanswered question instead or something similar?   Also, some of these questions are so old as to be irrelevant to now. For instance, if a question from 2008 was posted as "What is the best way of dropping this and using jQuery?" back in 2008, a plugin may not have existed that now does. So the good answer of "Try the jQuery plugin Drop-jQuery-and-try-jQuery" will not have been posted. And even if it is bumped, then a person that knows about this plugin may not put it as an answer because the answer is so old as to not matter to the asker now.


Prove that any continuous integer-valued function of a real variable is constant.

I'm stuck on a question which asks to prove that any continuous integer-valued function of a real variable is constant. In my lecture notes we are told that a map is continuous if the preimage of any open set is open.  How do I use this to answer the question? A full answer would be greatly appreciated as I can't seem to figure out how to solve it in my  notes, in analysis books or anywhere online.


Can a bounty be awarded for the same user in the same question multiple times?   Say a bounty was started and userX was awarded so now next to his question the bounty score appears.  Now, if a bounty is started again on the same question, can the same userX be awarded one more time?


How to copy directories with preserving hardlinks?

How to move directories that have files in common from one to another partition ?  Let's assume we have partition mounted on /mnt/X with directories sharing files with hardlinks. How to move such directories to another partition , let it be /mnt/Y with preserving those hardlinks.  For better illustration what do I mean by "directories sharing files in common with hardlinks", here is an example:  # let's create three of directories and files mkdir -p a/{b,c,d}/{x,y,z} touch a/{b,c,d}/{x,y,z}/f{1,2,3,4,5} # and copy it with hardlinks cp -r -l a hardlinks_of_a   To be more specific, let's assume that total size of files is 10G and each file has 10 hardlinks. The question is how to move it to destination with using 10G (someone might say about copying it with 100G and then running deduplication - it is not what I am asking about)


Replace arbitrarily many nested for-loops with a generator

I have a lists of lists, like this: indices = [[0, 1, 2], [0, 1], [0], [0, 1, 2], [0, 1]]  Now I want to loop over all of these indices, meaning that I want to go for the combinations [0, 0, 0, 0, 0], [0, 0, 0, 0, 1], [0, 0, 0, 1, 0], ..., in effect the same as for i in indices[0]:   for j in indices[1]:     for k in indices[2]:       ....  I know that this will lead to a combinatorical explosion pretty fast, but I know that everything I'll need this for is tractable. I am simply looking for a general way to write that, and I think one could build a (recursive?) generator for this, but I cannot wrap my head around how that must look like. If I knew all of the sub-lists had a fixed length, I would generate the product of the lens of the sublist and then get the binary/ternary/decimal/... representation of that number, however both the length of the sub-lists as well as the length of indices is variable.


Ubuntu install hangs at "Installing the 'grub2' package..."

So i'm trying to install Ubuntu on my laptop, it seems to work fine until it tries to install grub. I haven't seen progress the past hour and this is the second attempt.  I'm trying to install 13.10, using a Linux Live USB. I don't care about the contents of the laptop.   I've been trying to find instructions about installing grub before starting the installation, hoping that would solve my issues, but I came up empty.  Laptop is 2 years old, it used to run dual-boot windows 7 and Ubuntu. I'm now doing a fresh install of just Ubuntu.  I hope anyone knows how I can find out why it is happening.


Why do electrons form Cooper pairs below certain temperature?

Just a heads up - please make this answer understandable to around 1st year degree level physics - not PhD research. So I can understand it - thanks.  1) In solid state physics, why is it that below a certain temperature (KE of the electrons) do the electrons form Cooper Pairs / a condensate via BCS Theory?  I know its something to do with their KE being less than the attraction energy between the two electrons.  But a book i'm readings says its 'at low temperatures the electrons prefer to condense into pairs and make the superconducting state, and this is because it costs them less energy to do so'. So according to the book - why is it that above a certain temperature it costs them more energy to form a cooper pair (instead of staying as individual entities)?? And what does this have to do with their attraction.  2) Lastly, why is there an attraction at all at any temperature - aren't the electrons both negatively charged?


Simple Unpivot - erroneous Column Conflict

Did I stumble across a reserved word here or something?  For, the following statement:  SELECT [Type]  FROM (SELECT 'Receive' AS [Rec], 'Transfer' AS [Trx]) [data] UNPIVOT (     [Orders] FOR [Type] IN ([Rec], [Trx]) ) AS [unpvt];   produces this exception/error: The type of column "Trx" conflicts with the type of other columns specified in the UNPIVOT list.    Working Sample  SELECT [Type]     FROM  --(SELECT 'Receive' AS [Rec], 'Transfer' AS [Trx]) [data] (SELECT 'Rec_eive' AS [Rec], 'Transfer' AS [Trx]) [data] UNPIVOT (     [Orders] FOR [Type] IN ([Rec], [Trx]) ) AS [unpvt];   Database Explorer:


How can I represent multiple pins at the same location on a map?

I'm building a very small app that allows my users to post content to a map.  The home screen of the app contains a map with all of the posts (as seen below).  PROBLEMS  01 - if a user posts a post from the same area, two pins will be on top of each other so you won't be able to access one of them  02 - if a lot of content is posted it will be hard to click on each pin  03 - when you zoom all the way out, there will be too many pins  Can anyone recommend trying anything else please?


A curious logical formula involving prime numbers

Let $S$ be a nonempty set of natural numbers. Is the following formula $$ \exists p\ \bigl(\text{$p$ is prime } \rightarrow \forall x  \text{ ($x$ is prime)}\bigr)  $$ true or false on $S$? I know the answer to this question, but what would be the shortest way to arrive to the conclusion using some deduction system?


What are the recommended over-sampling or under-sampling techniques to handle multi-class imbalanced datasets for machine learning?

Many techniques are for two-class classification. What is the recommended techniques to over- or under-sample multi-class datasets?


Infinitely many primes of the type 5 mod 6.

Problem: Prove that there are infinitely many primes of the type 5 mod 6.  My professor did the problem and the proof was horribly long. Can someone show me a shorter version of the proof of this problem.


What's wrong with this argument for finding Aut($\mathbb{Z_p} \times \mathbb{Z_p}$)?

I happen to know that Aut($\mathbb{Z_p} \times \mathbb{Z_p}$) $\simeq$ $GL_2(p)$, and so has order $p(p^2-1)(p-1)$.  Which means something is wrong with the following argument:  An automorphism $\phi$ is determined by its value on the two generating elements $(1,0) $ and $(0,1)$ of $\mathbb{Z_p} \times \mathbb{Z_p}$.  These must be sent to elements of the same order, $p$. In fact every nonzero element of $\mathbb{Z_p} \times \mathbb{Z_p}$ has order $p$, so there are $p^2-1$ choices to which each generator must go. Therefore the number of automorphisms is $(p^2-1)^2$.  So I've overcounted by $(p^2-1)(p-1)$; I imagine some of the homomorphisms in my argument were not distinct, or not isomorphisms. is there a way to easily rectify for the overcounting? Or do we throw the whole argument away?


how to run the dialog command with proccess

Please look on my code – ( bash script )  I want to display both dialogs on the screen on the same time,   one dialog display the:  tail –f from - /var/log/proccess1.log  ,   and the second dialog display the:  tail –f from the file - /var/log/proccess2.log     but the sad fact is that I can display only one dialog and not both dialogs ( because when I run the first dialog , the second dialog will activate only if the first dialog will killed )   So I create process on the second dialog ( ….. ) &    , in order to display both dialogs    But …. the second dialog create process number but not create the second dialog GUI , ( seems that when we create dialog with process , the process not send the dialog to standard output )  So how to  run the second dialog with process but send the dialog GUI to screen ? , or other solution in order to display both dialogs on screen  My code       #!/bin/bash       # this dialog will locate the tail box on the top of the screen      dialog --begin 15 10  --tailbox   /var/log/proccess1.log  13 125         # this dialog will locate the tail box down in the screen      ( dialog --begin 37 10  --tailbox   /var/log/proccess2.log    13 125 ) &


with no answers.  But still the text of the bounty message says     This question had a bounty worth +50 reputation from juergen d that ended yesterday; you must award this bounty as soon as possible   Please remove the highlighted text if the question has no answers. I can't award it.


Close votes are to recommend closure flags, as reopen votes are to...what?

Those who have the "cast close and reopen votes" privilege can cast close and reopen votes to close and reopen questions.  For those who do not, they can raise recommended closure flags to close questions, but what could they do to reopen?    I've once posted a reopen request question on Music Stack Exchange Meta in order to have a question on Music Stack Exchange to be reopened.


Adjust table width to fit two-page column

I want to fit my table into a two-column page and I am using a table* package. This is my code:   \centering   \begin{tabular}{@{}lllll@{}} (table information) \end{tabular}   \label{tab:1} \end{table*}  However, the sentence is too long, so the sentence exceeds the page margin. Would really appreciate if someone could help!


Finding command execution time in hindsight

I've just executed a long-running process from the bash prompt. In hindsight, I wish I'd run time on it, or noted down the time at which I kicked it off.  Is there any way of getting this information retrospectively? The .bash_history doesn't seem to include timestamps.  In my particular case it's Mac OS X, but I'm interested in general Unix/Linux solutions.  To clarify, the process has now completed, and I'd prefer not to run it again unless absolutely necessary!


On skyrim I want to find more of the unusual gem but I can't

I want to find all of the unusual gems for the thieves guild but I can't find any, I only have 3, are they in dungeons or where?


Proof that the rank of a skew-symmetric matrix is at least $2$

Is there a succinct proof for the fact that the rank of a non-zero skew-symmetric matrix ($A = -A^T$)  is at least 2? I can think of a proof by contradiction: Assume rank is 1. Then you express all other rows as multiple of the first row. Using skew-symmetric property, this matrix has to be a zero matrix.   Why does such a matrix have at least 2 non-zero eigenvalues?


Look that every text is displayed below the picture. I would like every text to be displayed perfectly in the center of the picture.  Here is the code:     body {   left: 8%;   top: 10%;   position: absolute;   background-color: #6699cc; }  .box3 {  background-color: #191919;  position: absolute;  padding: 15px 40px 15px;  font-size: 12px;  color: #DDDDDD;  font-family: Verdana;  font-size: 12px;  width: 400px; }  .box3 > li {  display: block; }  .box3 > li span {  display: inline-block;  vertical-align: middle; }

           Skype name

              Gadu-Gadu number

              Email address

            How do you make every text display perfectly in the center of the image?  I will be very grateful for effective help.


Why is the Cartesian product of a set $A$ and empty set an empty set?

Let $A \times \emptyset = \{(x,y)| x\in A, y \in \emptyset \}$. We know there is no element in $\emptyset$. But how does it follow that $A \times \emptyset = \emptyset $?


how to save data in UTF-8 in mysql database?

I have a <textarea> element in my <form> which is supposed to save arabic text into a mysql database.   I have set the charset of my page as <meta charset='UTF-8'> I have also set the accept-charset = "UTF-8" in my <form> tag. And I have set the collation of the column in my database to utf8_unicode_ci  But whenever I submit the form, my database is saving the arabic text like so:Ø¨ÙØ³Ù’Ù…Ù Ø§Ù„Ù„Ù‘  Instead of saving it like so: كيف حالكم  I am using php as my backend. Can anyone guide me as to where I am going wrong?


I see POSIX mentioned often and everywhere, and I had assumed it to be the baseline UNIX standard.. until I noticed the following excerpt on a Wikipedia page:        The Open Group is most famous as the   certifying body for the UNIX   trademark, and its publication of   the Single UNIX Specification   technical standard, which extends   the POSIX standards and is the   official definition of a UNIX system.     If the official definition of a UNIX system is an extension of POSIX, then what exactly is POSIX? ,,, It surely seems to be a touchstone of the UNIX world, but I don't know how it fits into the overall picture.


When we're talking about spatial rotations is quantum mechanics, why do we need to resort to $SU(2)$? Why isn't $SO(3)$ enough?  I've read that $SO(3)$ isn't , and I've read about , and , but I'm falling down deeper and deeper into pure mathematics (esp. topology). Is there a "topology for physicists" explanation of what's going on here?


expected area of the intersection of a set of triangles made up points inside a circle, and the triangles must contain the origin

What is the expected area of the intersection of a set of triangles made up N points that are picked uniformly inside a circle. The triangles must contain the origin of the circle? The expected area of one random triangle that contain a circle of radius R is given by : $ 4/(3 \Pi) R²$, see :


I want to dual boot Ubuntu and Windows. I saw a lot of tutorials and they do partitioning, but I'm confused if I should do partitioning or just select the option "Install Ubuntu alongside Windows". Will I get the same result if I choose the first option in the installer?


I can't crack this one.      Prove: If $\gcd(a,b,c)=1$ then there exists $z$ such that $\gcd(az+b,c) = 1$ (the only constraint is that  $a,b,c,z \in \mathbb{Z}$ and $c\neq 0)$


If statement not working when used inside an action listener

I'm pretty new to java and have been working on learning how GUI's work. Through some tutorials, I managed to piece together a program to use a text box with the hope to incorporate a calculator I made as my first project. The area I'm focusing on is the button and action listener, where I'm trying to get an extra response when typing in "calc".  I've tried initializing the extra response outside of the program, but because of the string being called inside, I can't get it to work. I also tried calling the string outside but that still didn't work. I have an idea doing anything past this will require separately called functions, but I was hoping to start by figuring out this smaller part first.       static JTextField tf;     static JFrame frame;     static JPanel panel;     static JTextArea ta;     int count;     int num1;     int num2;     int exp;     char operator;     double answer;      static void GUI() {         frame = new JFrame("Thank you for reading this");         panel = new JPanel();         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         frame.setSize(400,400);         JButton button = new JButton("Test");         tf = new JTextField(15);         panel.add(tf);         panel.add(button);          JTextArea ta = new JTextArea();         ta.setEditable(false);          button.addActionListener(new ActionListener(){             public void actionPerformed(ActionEvent e) {                 String text = tf.getText();                 ta.append(text+"\n");                 if(text == "q") {                     ta.append("something random\n");                 }             }         });          frame.getContentPane().add(BorderLayout.CENTER, ta);         frame.getContentPane().add(BorderLayout.SOUTH, panel);         frame.setVisible(true);     }      public static void main(String[] args) {         GUI();     }      @Override     public void actionPerformed(ActionEvent e) {         // TODO Auto-generated method stub      }  }   I'm expecting to see "something random" appear below "calc" when it is typed into the text field. So far I receive nothing with the if statement


I wrote a c++ program. When the execution of that program, I should pass a string to that program. I executed my program as like below,  ./sample "ball!28sweetDecay"   When I run this program, I got the below error message.  -bash: !28: event not found   I see some characters in my arguments as '!28'. Couldn't I send this string as an argument? But I must send this string as an argument? How can I do this?


An alternative to "Exceed" when falling below a lower limit

I am trying to describe conditions falling below a lower limit. In this case there is a minimum temperature limit, and the actual temperature has fallen below this limit. I am drawn to use the work exceed, but I feel this implies the value is greater than the limit.  For Example, what is an alternative to exceeds in this sentence:  "The temperature exceeds the minimum temperature."


M is a square martix, and $φ^*$ : $V^* \to V^*$, then why $M^T=M_{φ^*_M}$?

Let M be a matrix, transpose $M^T$ is the matrix who's i,j component is the j,i component of M.      And  let $ \phi\in Hom(V,V)$, we define $\phi^*: V^* \to V^*$ by $\phi^*(f)(v)=f(\phi(v))$ where $V^*$ is the dual space of $V$.      $M_{φ^*_M}$ is the matrix representation of $φ^*_M$   Then how to prove $M^T=M_{φ^*_M}$


What is the reference plane used when the minimum focus distance is measured?

Once you know the MFD (minimum focus distance) for a particular lens, is that the distance from the subject to the front of the lens or to the camera sensor?


ESTA / Visa Waiver Program - volunteering

I am a german student, graduating this spring. I did an exchange year in 11th grade in Tennessee, USA. Since I´m still in touch with my friends and host family, I got a chance to volunteer in the local hospital. In the ESTA program condition it says, I can ´attend a short-term training´. So my question is, is my volunteer work, where don't get paid in any source, considered as a short-term training?  I appreciate every help I can get.  Aaron


Zeroing the content of a hard drive without destroying the filesystem

I've copied a lot of photos on an external hard drive from an old computer that was used by an old person and was probably infected by malwares. I've put the photos on another hard drive. Now my external hard drive is completely empty but I'm paranoid and I'd like to be sure there isn't any malware or malicious code left on the drive.   So I'd like to fill it with zeroes but without destroying the filesystem or the partition table. In a way, I'd like to get my disk back as if I'd just bought it.  Is it possible to do that and is there a Linux command to do that ?  My hard drive is formatted in NTFS with a msdos(mbr) partition table.


Is it possible to export labels based on Shapefile attributes into a DXF file?  I use QGIS 1.7.4.  I've been reading a CSV file and view it as a Shape Layer. With the help of attributes from the File I will label the points. Now I want a DXF export with the labels. However, only the Points in the DXF file Export.  I do not have ArcGIS.  I am using AutoCAD LT 2011 for viewing DXF files. In AutoCAD I have to go through the "Insert / Link & extraction" under only the possibility to find data from Excel.


How to delete specific values in a list?

I have a list which looks like this: my_list =  [['UK', 'Manchester City', 'Blue', '1','2','B'], ['ES', 'FC Barcelona', 'Blue', '2','1','C'],  ['IT', 'Juventus', 'White', '3','2','A'], ['DE', 'Borussia Dortmund', 'Yellow', '4','1','A']]   Now I want to edit my_list and actually delete the values in index0,3,4 and 5. This is my expected output:   my_list =  [['Manchester City', 'Blue'], ['FC Barcelona', 'Blue'],  ['Juventus', 'White'], ['Borussia Dortmund', 'Yellow']]   This is the code I tried: for list in my_list:     for idx in [0,3,4,5]:         del list[idx]                 print(my_list)   This is the output I get: IndexError: list assignment index out of range


Encrypt Passwords in PHP before sending through the url via GET

I have a form where I have a password field. When the users submits the form, all the fields including the passwords are clearly visible in the url when they passes through the URL to another php page. Is there any way to avoid this ? I dont want the password to be visible.


If $\text{Ext}_R^1(A,I) = 0$ for all $A\in ob(_R\text{Mod})$, then $I\in ob(_R\text{Mod})$ is injective.

Let $\text{Ext}^1(A,I)=0$ for all $A\in ob(_R\text{Mod})$, then $I\in ob(_R\text{Mod})$ is injective.  I got stuck by this problem. Any ideas?


Automatic start time when a link is clicked

I would like to seek your expertise with regards to the coding below:  this is the layout of my browser, so i divided my page into 2  <FRAMESET rows="5%,*" border=0>     <FRAME SRC="MENU.HTML">      <FRAMESET rows="50%,*">         <FRAME SRC="" NAME=1>         <FRAME SRC="" NAME=2>     </FRAMESET> </FRAMSET>   below is the code in which i would like to setup the start time automatic where in it will be the same start time in the label.          <title>Start and stop</TITLE>              <form>

   <input onclick="this.form.StartTime.value = getDateString();" type="button" class=button value="   START   " >  	    <input onclick="this.form.StopTime.value =getDateString();" type="button" class=button value="    STOP    "> 	    <input type="reset"  class=button value="   CLEAR   ">

       <input type="text" name="StartTime" size="17" id="date" class=select disabled="disabled">    | 00:00 |             <input type="text" name="StopTime" size="17" class=select disabled="disabled">

   </form>

     is it possible to have automatic stop as well when i clicked the stop button?


Actually i guess it is a easy question, but I could not find a answer for my datestring.  It is formated like this:  '2015-01-16T14:13:56+01:00'   I tried to parse it with:  datetime.datetime.strptime(timestring, "%Y-%m-%dT%H:%M:%SZ") datetime.datetime.strptime(timestring, "%Y-%m-%dT%H:%M:%S+%Z") datetime.datetime.strptime(timestring, "%Y-%m-%dT%H:%M:%S+HH:MM")   This seems to be wrong because it returns it does not match.


Shell script to copy every 512 bytes from a file

I have an input file of size 1040 bytes. I need to copy the first 512 bytes, skip next 8 bytes and copy the next 512 bytes, skip 8 bytes. I am able to copy the first 512 using dd command, but not sure how to put this in shell script to skip 8 bytes and copy the next 512 bytes. Any help please


In the famous Magdeburg hemisphere experiment up to about 30 horses were used pulling on both sides of the hemispheres.  Could I achieve the same effect (same force on the hemispheres) if I replaced half the horses with a wall, i.e. attach the hemispheres on one side with a wall and have 15 horses pull on the other side?


Creating a Windows 10 Install USB when FAT32 has 4GB max file size

So I am attempting to create a Windows 10 install USB on my MBP running macOS 10.14 Mojave. To create a bootable USB it needs to be formatted into FAT32, not exFAT. The issue is that when copying the .iso to the USB it fails because the file sources/install.wim is 4.4GB. I can't format as exFAT because I cannot boot from that format and I cannot use FAT32 because of the 4.4GB file. I used the command cp -rpv /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WINDOWS10/ after Boot Camp Assistant failed to create the  USB with a "Drive too small" error, even though it was a 16GB drive. When I wasn't paying attention, the cp completed and the installer booted, but failed with a missing: sources/install.wim error because the file can't be copied.  Is there any solution to this problem, or should I just burn a DVD with the installer on it?  EDIT: I forgot to specify that I was creating a USB for a PC, not a Mac. The Mac was just being used to create an install USB.  Heres the file:


A professor has offered me a summer research project at his lab. The last we had talked was on a Zoom call during which I was offered the position. He had then asked me to send my academic records after which he would give the other documents like Offer Letter, Visa Forms, etc. I have mailed him my records and have asked to discuss the project dates. He is not responding to my emails. It's been almost 20 days. I have also sent follow-ups, the last one being sent this Monday. He still hasn't responded. Has he cancelled my project? If so, why hasn't he informed? What should I do next? Should I send another follow up this Monday?


Is there a way to get a spacing which is half or quarter the length of \quad in mathmode?  Maybe there's an easy way to define a shortcut for such command?


Japanese Kanji not authorized on Worldbuilding?

When composing  on Worldbuilding, I wanted to give an example in Japanese. I used the typical canna input method.  As can be seen, hiragana and katakana were accepted without problems, but I wanted to write "China", and a red sign appeared saying that (paraphrasing)      It is not allowed to use the -character in the body of a post.   I replaced China with Japan, but had the same remark about the . I suppressed all kanjis and I got no complain, not even when clicking "Post".   Is there any reason for that or was that a bug, or should I have ignore that message and try to force the post anyway?


Comparing a strings value to the value of a boolean

I'm trying to compare the values of the boolean (all of which are 0) to the values of this string array data[] = "1,0,0,0,0,0,0,0,0,0,0,0,1". This is my code:  recipeIngrediants = new boolean[numberOfCuisines][numberOfIngrediants];         int i = 0;         while(file.hasNextLine()){             String temp = file.nextLine();             String[] data = temp.split(",");         for(int j=0; j < recipeIngrediants.length; j++){             String c = data[j];             if(c == "1"){                 recipeIngrediants[i][j] = true;             }             else{                 recipeIngrediants[i][j] = false;             }         }         i++;      }   I get an error saying that it is a type mismatch.  EDIT: Fixed the type mismatch error but it still gives me a value of false for all values in the boolean  Question:  How else can I compare these values to get the 2D array of recipeIngrediants to equal true at whatever position in data has a 1?


Defining custom commands with output dependent on the number of variables

I recently started looking into building custom commands in latex to make life easier and one thing that I wanted to do was create a command that outputs a diagonal matrix from the specified input values, which are the diagonal entries of the matrix. However, there arises an obvious problem which is that the dimensions will doubtless be different for each matrix that I want to define. I don't want to have to make a command for matrices of specific dimensions, so I was wondering if there was any way to make a command in order to print a matrix of a certain dimension depending on the number of variables that are input into the command. Or is the solution just to make a different command for the different matrices of different dimensions? For example: I may want to create a 3 x 3 diagonal matrix with entries a1, a2 and a3, so I would like to be able to write this matrix for example like this: \diagmatrix{a1}{a2}{a3}. At the same time, if I later wanted to create a 2 x 2 diagonal matrix, with entries b1 and b2, I would like to be able to do so with the same command like this: \diagmatrix{b1}{b2} So far I have managed to make the command for a 5 x 5 matrix, but it obviously would not work for any matrix of different dimension. This is the code for it: \documentclass{article}  \usepackage{amsmath}  \newcommand{\diagmatrix}[5]{% \begin{pmatrix} #1&0&0&0&0\\ 0&#2&0&0&0\\ 0&0&#3&0&0\\ 0&0&0&#4&0\\ 0&0&0&0&#5 \end{pmatrix}% }  \begin{document}  $\diagmatrix{1}{2}{3}{4}{5}$  \end{document}  Is there any way to extend this to make it work for any dimension? I am also aware that, in any case, the maximum number of supported variables is 9, so I would not be able to make matrices larger than 9 x 9 with a command like this, but it would still save time for the smaller matrices.


Today I found that my 145 reputation deducted from my account so can any one help about this?


Can I create a common include file in HTML?

I am just wondering if this is possible. I have almost 50 html files in my project and have almost common include files like bootstrap, angular, jquery ui etc.   Can I write a common file say include.html that is similar to say import java.util.*. my include.html will contain 3-4 entries of my common JS and CSS files and then I can include that file in my each html page?  like say user.html:  <!DOCTYPE html> <head> import include.html (or any other appropriate name or file format) </head>....   I do not want common header and footer files I want to include required files in one shot by including one html file.


Is the description for 'Moderation' on the privs page accurate?

I just noticed this block of text on  in the right coluomn.  Moderation Help decide what questions and answers float to the top or participate in suggesting new features.  ...or participate in suggesting new features. What??? Since when is suggesting a new feature moderation? If anything, it would fit in with either Communication or Creation:  Communication Communicate with fellow users in chat rooms, meta-discussion, and comments, or participate in suggesting new features.  The  privilige is categorized as a Communication privilege.  Creation Create questions, answers, tags, and other content, or participate in suggesting new features.  Either way, suggesting new features sure ain't moderation. Request: Take out the notion that suggesting new features is moderation.


When a car's engine injects fuel into the cylinder chambers, the reaction creates a force that generates rotational momentum to the shaft and over the transmission, it translates that power to the wheels, right?  But, something's bothering me, how does the car actually move, is it dependent on the force of friction? Wheels have a contact with the road in one exact point and when the drive gets to rotate them, a force is exerted on the road in the direction of movement and there is friction that is counteracting it.  Is the key to get a car properly moving to have the drive force equal or less than the force of friction to keep that point locked to the ground and use the rolling of the wheel for translational displacement ie. moving forward? If it's bigger than the force of friction, that would cause the wheels to spin in place?  Am I completely off or am I getting something right? If there's a knowledgeable person on this topic, I'd greatly appreciate some insight, perhaps even a bigger response with some basic vehicle physics.


I installed Ubuntu and then Windows 8. How can I make GRUB work again so that I can choose which system I want to boot?


80s (or earlier) short story, main character can "freeze" (actually slow down) the world around him, but ages faster if he does it repeatedly

This is about all I can remember of a short story I read maybe 35 or more years ago in Argosy (UK) magazine; can't remember the author, or even how it turned out.  Main character finds one day spontaneously he can enter an accelerated state which renders him invisible. The people, in fact the world around him, appears frozen but is actually progressing at an infinitely slow pace. He can get his day's work done and emerge to find only seconds or minutes have passed in the 'normal' world.  Of course it's a parable of relativity but nicely written, accessible and enlightening especially to the younger reader. He notices after doing this repeatedly he is ageing fast.


Should you be allowed to run in a mod election if you've been banned for bad behavior?

There is a candidate in the Server Fault election (which is ending shortly) that has been suspended from the main site for behavioral reasons more than once. He's also been kicked from chat, and banned on at least three other SE sites. He even had his original nomination deleted by Shog9, because of the profanity it contained. His nomination was reinstated after he cleaned it up.  Now, let's be real, there's no chance he's going to win. But it raises an good point. Why is someone that's been such a behavioral problem even allowed to run in the first place? Shouldn't someone with a history like that be prevented from running for the most powerful position in a community?   At the very least, shouldn't his election profile show the number of times that his user account has been banned on any SE site very clearly and prominently?


What do the financial questions for a Standard Visitor visa application really mean?

Can someone please help differentiate the following application questions and what they really mean?  What is the cost to you personally of your trip in GBP(£)?  The total amount of money you have for this trip?  How much will they be paying towards your trip (in GBP £)?  What is the total amount in GBP(£)?


I have changed my Apple ID (email and password) on my computer.  However, my iPhone 5 still shows the old email address which is grey so I can't change it. I don't remember the password for that email address so can't log on and can't delete it. How do I recover the password ?


Is there a command to center the active window in the middle of the screen?  Compiz has a feature called "center", but it effectively shows the window fully maximized.  I'm looking for the size to be smaller and I'm unclear on how to change it to a smaller size.


How to mock responses when the callout is being made in a dependent class?Question

I have a WrapperClass which calls HelperClass.doSomething(). doSomething() makes two callouts: callout1, do something, callout2, do another thing, return. I want to write tests for WrapperClass. Is it possible to do so? If yes, how?


When exactly are we looking back at the past from future. Is it at the start of the due time or at the end of the due time?

My question is simple and specific. Please look at the following What is the difference between   I will submit the report by 5 pm tomorrow.  I will have submitted the report by 5 pm tomorrow.    If they are not the same, then please tell me what the difference is between them. If they both are one and the same and the difference is one of POV, then please look at following. When I say, I will have submitted the report by 5 pm tomorrow. My question is what time am I referring to? Is it at 5 pm tomorrow or starting from 5:01 pm and not before. I mean this also includes the possibility of me submitting the report at 5 pm also? Am I right? And also, when I say  I will submit the report by 5 pm tomorrow. (Looking from now)  I will have submitted the report by 5 pm. (Looking from 5:00 pm or 5:01 pm? I think after 5:00 pm because according to you by 5 pm includes either 'before' or 'at')   Do the two sentences have the same meaning? Is the difference based on POV? If not, then please tell me what the difference is between them. This has been confusing me for almost two days now. I have spent almost two days on this and still I am clueless about this. Thank you so so much.


Minimal prime ideals consist of zerodivisors

I don't find the proof for this little demonstration ...     Let $P$ be a minimal prime ideal of $A$. Show that $P$ is contained in the set of zero divisors of $A$.


Is the phrase "I just sucked it out of my thumb" used in American English?

I was born and raised in South Africa. We frequently used the term "to suck out of one's thumb", implying that an answer was just a wild guess or the notion had no evidence but was rather just surmised. At best it was the product of a personal thought experiment.   Is the phrase used elsewhere? I live in the USA and almost never hear it. Do Americans understand it? Can they figure it out or will they conjure up graphic literal images of my thumb in my mouth?


When I am using Tor, and not using the Tor bundle there is a possibility of DNS leaks in certain situations.   What can be done to minimize it? Is it possible to resolve DNS via Tor?


How can I make discord not show what game I'm playing?

Discord will show what game you're playing, but I don't want it to do that.  Is it possible to make discord not show the game currently being played?


In issue 5 of the recent Incredible Hulk ongoing (vol. 3), it is revealed that      Dr. Doom   separated the Incredible Hulk and Bruce Banner. He does this using an adamantium chainsaw.   Image blurred to protect the innocent spoiler.  I was under the impression that adamantium was pretty much impossible to find and use outside of Ultron and the Weapon Blah program. Is it common enough that it's no big deal for the blurry fellow above to have gotten an adamantium chainsaw?


Simplifying Complex Numbers in Exponential Form

$(a)$ Suppose $p$ and $q$ are points on the unit circle such that the line through $p$ and $q$ intersects the real axis. Show that if $z$ is the point where this line intersects the real axis, then $z = \dfrac{p+q}{pq+1}$.      $(b)$ Let $P_1 P_2 \dotsb P_{18}$ be a regular $18$-gon. Show that $P_1 P_{10}$, $P_2 P_{13}$, and $P_3 P_{15}$ are concurrent.   I already proved part $(a)$, and used it to prove part $(b)$ by making the diameter of the $18$-gon one unit and defining $P_1 P_{10}$ as the real axis and then plugging both $P_2 P_{13}$ and $P_3 P_{15}$ into $p$ and $q$ to get $$ z_{1} = \dfrac{\mathrm{e}^{\mathrm{i}\frac{\pi}{9}} + \mathrm{e}^{12\mathrm{i}\frac{\pi}{9}}}{\mathrm{e}^{\mathrm{i}\frac{\pi}{9}} \cdot \mathrm{e}^{12\mathrm{i}\frac{\pi}{9}} + 1} $$ and $$ z_{2} = \dfrac{\mathrm{e}^{2\mathrm{i}\frac{\pi}{9}} + \mathrm{e}^{14\mathrm{i}\frac{\pi}{9}}}{\mathrm{e}^{2\mathrm{i}\frac{\pi}{9}} \cdot \mathrm{e}^{14\mathrm{i}\frac{\pi}{9}} + 1} \;. $$ Then, I set $z_{1}$ and $z_2$ equal and simplified to get $$ 0 = \mathrm{e}^{8\mathrm{i}\frac{\pi}{9}} - \mathrm{e}^{6\mathrm{i}\frac{\pi}{9}} - \mathrm{e}^{5\mathrm{i}\frac{\pi}{9}} + \mathrm{e}^{3\mathrm{i}\frac{\pi}{9}} + \mathrm{e}^{2\mathrm{i}\frac{\pi}{9}} - 1 \;. $$ However, I can't seem to get past this part to get something like $0=0$ that proves part $(b)$. Any tips?


For the inverse of a matrix, we learned that to prove two matrices are inverses of each other, you must show that $AB = I = BA$. However, today in class someone claimed you only have to show either $AB = I$ or $BA = I$ to prove they are inverse. I know the commutative property doesn't apply to matrices, so can someone provide an example where $AB = I \ne BA$?  Edit: The question type goes as follows: Given matrix $A$ and matrix $B$, show whether or not the two are inverses. -For this question, do we need to show both $AB = I$ and $BA = I$ or will one or the other suffice?


I have a polygon layer with multiple sectors, I created for each one a pie chart. My problem is some of thoses pies are not displayed, but when I zoom I find them. I would be pleased if you tell me how to have them all displayed.


Is "can’t help but" considered to be a confused mix of the expressions "can but" and "can’t help"? If not, what is the difference between "can help but" and "can’t help but"?


Javascript string search double and single quote using RegExp

I'm using the following code to search sub string in a string mystring.search(new RegExp(substring, 'i'))  Reason why I am using new RegExp is, I want to search case insensitive. However, when there is a string like var mystring = '10" stick'; and I want to search 10", the code above does not return any result. It's clearly because of new RegExp and double quote. Is there any particular flag that needs to be passed in new RegExp? I googled a lot but couldn't find any solution. What am I missing?


Prove that there exist countable ordinal $\xi$ such that $\xi=\omega^\xi$.  The $\xi= \sup \{b^i \mid b_1=w, b_{i+1}=w^{b^i}\}$ should work. But how to prove that $\xi$ is countable?


Prove or find a counterexample: The product of any three consecutive natural numbers is divisible by 6.  Answer  Let n=1,             Since xeN is arbitrary p(N) holds for all xeN.  (n).(n+1).(n+2),  (1).(1+1).(1+2)= 6  Thus,6|6


Is there equivalent for PHP's print_r in Ruby / Rails?

In PHP you can do:  print_r($var) or vardump($var)   which prints "human-readible" information about variable.  Is there equivalent functions / helpers for those in Ruby / Rails ?


High memory utilization in the Linux server

JVMS heap usage and GC is working as expected but we are still observing more than 90% MEM usage in Linux top command.  Please advise.


Is there a general formula for the number of elements of order $k$ in $S_n$?

How many elements of  order $n$ does $S_7$ contain? Is there a general formula for to compute how many elements of order $k$ (for a given) in $S_n$?


Remove a user's password using "net" command'

Is it possible to remove a user's password using the net command?  I tried "net user <name> *" and just hitting return twice, but this does not work as expected. Is there any other way to do this? (I'd gladly take non-net commands, as long as they are built-in in XP SP3).  Edit: Seems, I did not make my intention clear. I don't just want to change the password, but remove it completely (so that the user may log in without having to supply a password).  I'm familiar with the "net"-reference and have searched online for several hours, but could not find a hint on how to do this.


Get back my event on button after .remove() and .append()

I have a click event on a checkbox button which I remove in my click event and I append it again with another value. My problem is the click event is not working anymore after the new append.  <input class="year" type="checkbox" value="2015" /> 2015
   $(".year").click(function(){     $(".col-md-12").remove(); //i remove the div which contains the checkbox       $.ajax({         url: "criteria_search",                   type: 'POST',          data: {             criteria: "authors",              value: "test"          },         success: function(data) {              articles = $.parseJSON(data)             $("#AppendToElem").append("

 Search Results <\/h2>
 There are<\/span> 3974<\/strong> results for:<\/span> Computer Animation and Virtual Worlds<\/strong> <\/p>
 <\/a> <\/p>

 Filter List <\/h3>
  Year <\/label>
");                $.each(articles, function(index, jsonObject){                 $("#AppendToElem").append("<input class=\"year\" type=\"checkbox\" value=" + jsonObject.date.date.substring(0, 4) + " /> " + jsonObject.date.date.substring(0, 4) + "
")              });         )     }); });   And after I clicked on my checkbox the second time the click event is not handled. How can I fix this?


"There is a large number" Or "There are a large number"?

Situation:  I am composing this phrase for a real forum discussion in person:   There are a large number of proverbs/idioms in English (and doubtless additional ones in American). Some are entirely regional and if you don't live in that region you are unlikely to hear them.  It is not easy either sometimes when you associate the situation that includes a cultural background [when you translate/interpret the Indo cultural things for Westerner you will find it].  Thank you.  Question: Any recommended advise whether I should use: "There is a large number" OR "There are a large number"?


Can you lift Thor when he is holding Mjolnir?

I was wondering:  If no one can lift Mjolnir (Thor's hammer), can one lift Thor while he is holding his hammer?


Should we be worried by the V1 SHUTDOWN recaptcha?

It looks like ye old Google RECAPTCHA is being decommissioned but we still use it on data.stackexchange.com  Google decided to warn us with this "NUCLEAR HAZARD" style image.    So, dear site owners, let me direct you to .


"The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192"

$ sudo apt-get update W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com maverick Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192 W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/maverick/Release   W: Some index files failed to download, they have been ignored, or old ones used instead.   How can I remove these warnings? Running apt-get update has given me these warnings from the beginning of my fresh 10.10 install.


I am currently trying to change a HWaddr persistently. ifconfig eno0 down, ifconfig eno0 hw ether 01:02:03:04:05:06 and ifconfig eno1 up works fine, but I could not find a way to make this persistent.   I found , which suggests to add net.ifnames=0 biosdevname=0 to GRUB_CMDLINE_LINUX in /etc/default/grub and run update-grub. This did not change anything for me.  Also, like suggested in  setting /etc/network/interfaces to  auto lo iface lo inet loopback pre-up ifconfig eno1 hw ether 01:02:03:04:05:06   did not work (Hardwareadress just stays the same).  The second advide was to use udev. I tried SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}==01:02:03:04:05:06, ATTR{dev_id}=="0x0", ATTR{type}"=="1", NAME="eno1". While running udevadm control --reload-rules && udevadm trigger --subsystem-match=net seems to change something (as one can see using udevadm control, it does not change the hardware address. After a reboot, the adress also stays the same. Does someone have an idea how to further debug this?


Is 1GB + 1GB RAM better than 2GB +0.5GB?

My laptop has two slots for RAM, and currently has two 512 MB chips, for 1 GB.  Windows XP is running terribly slow on it, so I want to upgrade the RAM.  I could buy two 1 GB chips to replace both of the current 512 MB chips, to give me 2 GB of RAM.  Or, the price is the same to buy one 2 GB chip, to replace just one of the 512 MB chips, and give me 2.5 GB total.  The RAM it takes is PC2-4200 533MHz DDR2.  What do you think would be better: buying two 1 GB chips so it can take advantage of dual-channel operation, or buying one 2 GB chip to end up with more total RAM but not dual-channel operation?  Like I said, price is the same, so performance is the only consideration.  I'm not doing anything especially intensive like video or photo editing -- just having multiple Office programs open, playing music, browsers, etc., but currently even opening the first application takes forever.  If it matters, the laptop is a Toshiba Qosmio G25-AV513 running Windows XP Media Center SP3.  Thanks! Kevin


Is it possible to prove that an elephant and a human could jump to the same height?

Is there a physics argument, based on scaling, that leads to the conclusion that an elephant and a human could jump about same height?  Could this be extended to any two creatures with different masses?


Past Perfect Continuous VS Past continuous

Do these two sentences mean the same?   When I arrived, Lisa was waiting for me. When I arrived, Lisa had been waiting for me.


Android 4.4: How to get the Easter Egg and unlock the Dessert Case daydream?

Similar to , does 4.4 KitKat have similar or other ones?


When using Two-Weapon Fighting, are your bonuses still added to the offhand attack roll?

I understand how offhand attack works. However, when you roll to hit, would you still add your bonuses to the attack roll?


someone explain what does the keyword strictfp mean in the class below?  public strictfp class Demo {         public static void main(String[] args) {                 double d = 8e+307;                 /** affiche 4 * d /2 donc 2 * d */                 System.out.println(4 * d / 2);                 /** affiche 2 * d */                 System.out.println(2 * d);         }  }


There are a lot of language-specific package managers like cpan for perl, cabal for haskell etc. When we want to install some software, it can sometimes be installed from a corresponding repo, with installation instruction just like (say, ) npm install yaxy or cpan something or cabal install something.   These package managers have slightly different syntaxes, they all need root privileges and/or custom setup, or (in case of Yaxy) just a newer version of interpreter (nodejs packaged by Ubuntu was too old to run it).  Is there a wrapper for different package managers that unifies/automates setup for different package managers?  Edit: what I want is a way to execute installation command like that npm install yaxy and make it working without manual installing system npm+nodejs, getting non-functional executable, finding the simplest way to install fresher nodejs on my system, reinstalling...


Accessing a range of value in Python's tuples

I have the following tuple:  tuple = (65,67,5,67,34,76,67,231,98,67)   When I did the following:  print tuple3[2:8]   I got:  (5, 67, 34, 76, 67, 231)   I thought that 98 should be also included. Isn't 98 on the index number 8? Why isn't 98 included?  Thanks.


How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?

During self-study, I ran across the question of how many ways six numbers can be chosen from the numbers 1 - 49 without replacement, stipulating that no two of the numbers be consecutive.  I can obtain a simple lower bound by saying that, in the worst-case scenario, when you choose a particular number, there are now three numbers that cannot be chosen next.  For example, if I first pick 17, then I can't choose 16, 17, or 18 for the remaining choices.  This gives me the lower bound  $$\frac{49*46*43*40*37*34}{6!} = 6,773,770 \frac{8}{9}$$  This is about 48% of ${}_{49}C_6 =  13,983,816$.  The real answer must be bigger (and an integer).  I haven't found a way to calculate it, though.  The original problem asked to show that the probability of having non-consecutive integers when you choose six is greater than 50%, so if the problem is complicated to count exactly, better approximations that show the answer is above 50% would also be appreciated.   Of course, I can use a computer to do the counting, but I'm interested in learning what methods I'm missing.


Post-increment and pre-increment within a 'for' loop produce same output

The following for loops produce identical results even though one uses post increment and the other pre-increment.  Here is the code:  for(i=0; i<5; i++) {     printf("%d", i); }  for(i=0; i<5; ++i) {     printf("%d", i); }   I get the same output for both 'for' loops.  Am I missing something?


Substituting values in multivariate polynomial in GAP

given a polynomial $p(x,y)$ from $\mathbb Z[x,y]$. I want to substitute $x=1$ leaving $y$ as it is. The command Value(p,[1,y]) does not work. Can you give me a hint?  After that it gets a little more complicated. Let  $$p(x,y)=x^6+y^6$$ After substituting $x=1$ we have $p(1,y)=1+y^6$. Given a natural number $j$. I want to find all expressions $y^j$ in $p$ and substitute these $y^j$ by $1$ and the others by $0$. In this case (and for $j=6$) we would get $1+1=2$. If $$p(x,y)=x^4y^2+x^2y^6$$ we should get $0+1=1$. Is there any way to do this?  Thanks for reading! edit: Well, it turns out I used the function Value wrong. The right code for my problem would be Value(p,[x,y],[1,y]). So my first question is solved.