Error after sudo-ing "sudo: must be setuid root"

On a colleagues computer, everytime I use a sudo command, I get this error:  sudo: must be setuid root  I tried various things mentioned on the internet, like changing the permissions to 4755 from a live cd, but even this command from a live-cd   sudo chmod 4755 /media/device/usr/bin/sudo  gives the same error.  EDIT: The colleague told me that he executed this command, god knows why :/  sudo chmod -R 777 / or sudo chmod -R 777 He isnt exactly sure.


How can I spawn a group of mobs within a certain radius?

I want to spawn multiple mobs within say, a 20x20 radius or so. The coords are: -277, 94, -37 (the center)  All I have right now is:   summon area_effect_cloud ~ ~-9 ~ {Passengers:[{id:zombie},{id:zombie}]}  Thank you.


We all know that Math is the science's mother and it's applied in all areas, I have an idea about where functions and geometry calculus ans stats are applied (in economic, banks, building ...), but I have no idea where can we apply algebra in real life, I mean like groups, rings and polinomials, I try to think where it could be usefull but I i find nothing.  I was thinking that if I am studying groups and rings only to teach people those notions which will also teach other's then it has no sence !!!!!!!!  any body give me some uses of groups and rings in the daily life  thanks


how to increase the open file descriptor size in ubuntu

i want to increase the open file descriptor size in linux current size is   ulimit -n   returns 1024 i want to increase it to 65535 because my elasticsearch process needs it  here is the link i am following    i did added following line in /etc/security/limits.conf  *     soft   nofile  1024 *     hard   nofile  65535  root     soft   nofile  1024 root     hard   nofile  65535    rebooted the system and ulimit -n still returning 1024  another solution i added these lines in /etc/security/limits.conf   *    soft nofile 64000 *    hard nofile 64000 *        -  nproc   16384 root        -  nproc   16384 root soft nofile 64000 root hard nofile 64000   and  /etc/pam.d/common-session needs to have this line in it:  session required pam_limits.so   and added following line in /etc/pam.d/common-session-noninteractive :  session required pam_limits.so   rebooted the system and it did not worked either  followed this link as well   it gives error on the last command    ulimit -n unlimited bash: ulimit: open files: cannot modify limit: Operation not permitted   and    sudo ulimit -n unlimited sudo: ulimit: command not found   my elasticsearch process is giving me this error  [1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]   any help would be appreciated


Colour cannot be applied in material mode

Whenever I change the object from solid mode to material mode to apply colour I am facing issues:  The outline of the object I created vanishes completely. It shows an orange outline only. [   When I go to apply colour, it does not respond to the command.


What are the rules for a long fall into water?

Normally when a player falls they take 1d6 bludgeoning damage when they hit the ground per 10 foot they fall. Are there any RAW for a player hitting water? At what height does hitting water in DnD become dangerous. In reality if you hit water from high enough it is the equivalent of hitting concrete and a I imagine from even a safe hight a player that dives badly may hurt themselves?


Let $f:[0,\infty]\to R$ be differentiable on $(0, \infty)$, and $f'(x)\to b$ as $x \to \infty$. Show that $\lim_{x \to \infty}\frac{f(x)}{x}=b$

This is actually part (c) of the original question. Part (a) asks to prove for any $h>0$, we have $\lim_{x\to\infty}\frac{f(x+h)-f(x)}{h}=b$. Part (b) asks to prove if $f(x) \to a$ as $x\to\infty$, then $b=0$. I know how to do (a)(b) using Mean Value Theorem. I think I should use Mean Value Theorem here. For any $x>0$, there exists $c\in (0, x)$ such that $f'(c)=\frac{f(x)-f(0)}{x}$. But as $x\to\infty$, $c$ may not approches to $\infty$. I don't know how part (c) is related to (a)(b). I can't figure out whether I should use the trick of add and subtract or others.


Do you "slump on a bed" or "slump onto a bed?"

Is one of them the correct option? Or they mean different things?  On Google maps I got these results:   (9K results)   (3K results)  Example sentence:     Without permission, he slumped on/onto my bed and lay on his back.


Changing values of class instances in a function

I wrote the folloing code to test how to change values of class object in a function.  using namespace std;  class test{ public:     int a; };  void runer(test testXX){     testXX.a=10; }  int main() {     test test1;     test1.a=5;     runer(test1);     cout<<test1.a;     return 0; }   When I run the following code the output is 5 and not 10. Is it because I can't change the values of class instances, like I can't change the values of array members without using pointers? I would be grateful if someone could clarify that!


Consider $f_n, f \in L^2(d\mu)$, $f_n(x) \to f(x)$ a.e. and $\|f_n\|_2 \to \|f\|_2$. Use Egorov's theorem to show that $f_n \to f$ in $L^2(d\mu)$.

Q: Consider $f \in L^2(d\mu)$, $\{ f_n \} \in L^2(d\mu)$, $f_n(x) \to f(x)$ a.e. and $\int |f_n|^2 \, d\mu \mathop{\longrightarrow}\limits_{n \to \infty} \int |f|^2 \, d\mu$. Use Egorov's theorem to show that $f_n \to f$ in $L^2(d\mu)$.   For any $\epsilon$, by Egorov's Theorem, there exists a $A_\epsilon$ such that $f_n$ converges uniformly to $f$ in $A_\epsilon$ and that the measure of the complement $m(A_\epsilon^c) < \epsilon$. Then for large enough $n$, $|f_n - f| < \epsilon$ for all $x \in A_\epsilon$.  If $f_n$ and $f$ are supported on a set of finite measure, which is not given, then it would be simple to show that $\int_{A_\epsilon} (f - f_n)^2 \, d\mu$ is arbitrarily small.  If $f_n$ and $f$ are bounded, which is not given, then it would be simple to show that $\int_{A_\epsilon^c} (f - f_n)^2 \, d\mu$ is arbitrarily small.  However, we are not given that $f_n$ and $f$ are bounded or supported on a set of finite measure. So, I'm not sure how to approach this problem.  I'm not using the given that:  \begin{align*}   \lim\limits_{n \to \infty} \int |f_n|^2 \, d\mu &= \int |f|^2 \, d\mu \\ \end{align*}  Which means that the $L^2$ norm of $f_n$ approaches that of $f$. I presume that I'm supposed to use that but I don't see how.


Can I run an HTTP GET directly in SQL under MySQL?

I'd love to do this:  UPDATE table SET blobCol = HTTPGET(urlCol) WHERE whatever LIMIT n;   Is there code available to do this? I known this should be possible as the  include an example of adding a function that does a DNS lookup.  MySQL / windows / Preferably without having to compile stuff, but I can.  (If you haven't heard of anything like this but you would expect that you would have if it did exist, A "proly not" would be nice.)  EDIT: I known this would open a whole can-o-worms re security, however in my cases, the only access to the DB is via the mysql console app. Its is not a world accessible system. It is not a web back end. It is only a local data logging system


What happens to gravity in the middle of the earth?

So I was curious about, what if we make a tunnel from one side of the earth, to the other side of the earth? Gravity is ofcourse always negative, which makes you "fall" and not "float".  If we take this image, let's imagine that the BLACK LINE in the midle of the earth, is a tunnel from one side of the earth, to the other side of the earth.  The red DOT is the midpoint, where something in theory, should happen to gravity that is out of our forces.  What would happen, if a human were to be in the red dot? Would the human just stay there for eternity?  Notes: Imagine that the being in the center couldn't kill you, neither would it bring you in contact of any substance. Just a long tunnel with nothing but the tunnel itself.


What data structure is conducive to discrete sampling?

I have a collection of values and associated probabilities for each value (all positive, but far from being equal). I would like to sample from this distribution many times. One technically correct way to do this is linear search, which would be like this:  def sample(xs,ps,p):      for i in xrange(len(ps)):         if ps[i] <= p: return xs[i]   in Python notation. Then for sampling you would take p=random.random(). This linear search approach is very slow if xs and ps are very large. Accordingly, I want to do something along the lines of binary search. My first idea was to build a binary tree, and sample by traversing the tree using a random bit sequence (go left if a bit is zero, right if it is one). I would build the tree by splitting the list of cumulative sums of probabilities in a way which resembles quicksort: the left part of the tree is the values <= 1/2, the right part of the tree is the values >1/2, and then I recurse, so that the LL part of the tree is the values <= 1/4, the LR part is the values >1/4 but <=1/2, etc.  I actually did implement this on a toy example, where the cumulative sum of the probabilities was [0.26,0.91,0.99,1]. (So 26% of the time you get the first value, 65% of the time you get the second, 8% the third, 1% the last).   I wind up with two problems. One problem I already fixed: there are certain nodes that only have one child based on the sorting mechanism above, such as the first movement to the right in my example. This was easy enough to fix: I just don't change the tree and appropriately update the splitting mechanism, applying it to what I already have.   But by doing it that way, all values that are located at a given level of the tree become equally likely. So the first value corresponds to L (1/2), the second value corresponds to RL (1/4), the third value corresponds to RRL (1/8), and the last value corresponds to RRR (1/8). These are very different from the probabilities that I wanted!  So my question is: how can I build an efficient data structure and traversal algorithm for a sampling procedure like the one above?


While solving a problem I came to an answer $\frac{1}{\sqrt{3}+1}$.  But this was not the answer.   The answer was $\frac{\sqrt{3}-1}{2}$ which comes on rationalisation of my answer.  Then I divided both results and get the same decimal value.  Then why do we need rationalisation if it doesn't change decimal value?


How do I install Ubuntu on a unformatted harddrive?

I would like to install Ubuntu on a computer with an unformatted hard drive, do I need to format my harddrive before installing Ubuntu, or can I just install Ubuntu without any problems?  Greetings, Bart


A paper I received to review has (independently) duplicated work that we are writing up. How to proceed in light of peer-review confidentiality?

I did some research with some collaborators, and we have been writing an article ("paper A") describing the work.  A few days ago I received a request to review an article ("paper B") that covers most of our work. The authors of paper B have clearly worked independently on the same topic and beaten us to submission. (And fair play to them.)  This leads me to a number of related dilemmas:  The first, and I think easiest to resolve, is whether I have a conflict of interest in reviewing paper B. I think I can write a fair review, but I intend to tell the editor and allow them to decide whether I should proceed.  The other dilemmas arise mainly because I am bound by peer-review confidentiality. I should note that paper B is not available as a preprint.  Can tell my co-authors about paper B? I am convinced that confidentiality forbids me from showing paper B to them, but can I tell them that it exists and what it covers? My feeling is that the answer is 'no'.  But then, if I cannot tell my co-authors about paper B, then it seems I have to allow our paper A to proceed to submission even although I know of the overlap with paper B.  I am extremely uncomfortable with this, although one can take the view that since our work was independent, our paper A could still be published.  Furthermore, my first impression is that paper B is not suitable for the general journal to which it was submitted, but that I would recommend acceptance to a high-quality specialist journal, such as the one to which we intended to submit our paper A. This raises an unpleasant prospect: if our paper A proceeds to submission and publication, the authors of paper B might believe that I had rejected their paper and plagarized their work (a situation discussed in ). This situation could arise even if I turn down the review request. Naturally, I want to avoid this.  How should I proceed? Could I ask the editor for permission to inform my co-authors about paper B?


Does a polynomial that's bounded below have a global minimum?

Must a polynomial function $f \in \mathbb{R}[x_1, \ldots, x_n]$ that's lower bounded by some $\lambda \in \mathbb{R}$ have a global minimum over $\mathbb{R}^n$?


Find all the ordered pairs $(x,y)$ such that $x^y=y^x$.   So the only ones that i find are when $x=y$ such as $(1,1)$ because $1^1=1^1$. However, I'm not very familiar with ordered pairs?  Any help?


an error "symbol(s) not found for architecture x86_64 & linker command failed with exit code 1 "

Sorry if it's a duplicate question, but I've been searching for solution since yesterday and I haven't found out yet..   I'm using CLion on mac, and my compiler is from xcode so i think it's clang. Any help would be appreciated!! Do I need to use gcc? or do I need to fix my cmake?  here's an error message.  [ 33%] Linking CXX executable bag Undefined symbols for architecture x86_64:   "Bag<int>::add(int)", referenced from:       _main in main.cpp.o   "Bag<int>::print()", referenced from:       _main in main.cpp.o   "Bag<int>::Bag()", referenced from:       _main in main.cpp.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make[3]: *** [bag] Error 1 make[2]: *** [CMakeFiles/bag.dir/all] Error 2 make[1]: *** [CMakeFiles/bag.dir/rule] Error 2 make: *** [bag] Error 2   Here's main.cpp  #include <iostream> #include "Bag.h"  int main() {     Bag<int> temp;     temp.add(1);     temp.print();      cout << endl;      return 0; }   Here's Bag.h.  #ifndef BAG_BAG_H #define BAG_BAG_H  #include <vector> #include <cstdlib> #include <iostream> using namespace std;  static const size_t CAPACITY = 100;  template <class T> class Bag{ public:     Bag();      size_t size() const;     bool empty();     bool check(const T& item);      void resize(size_t new_size);     void clear();     void remove(const T& item);     void add(T item);     void print();  private:     T* data;     size_t _size; };   #endif //BAG_BAG_H   Here's Bag.cpp.  #include "Bag.h"  template <class T> Bag<T>::Bag() : data{new T[CAPACITY]}, _size{0} {}  template <class T> size_t Bag<T>::size() const {return _size;}  template <class T> bool Bag<T>::empty() {  }  template <class T> bool Bag<T>::check(const T &item) {  }  template <class T> void Bag<T>::resize(size_t new_size) {     T* temp = new T[new_size];      for(int i = 0; i == _size; i++)         *data++ = *temp++;      delete [] data;     this->data = &temp; }  template <class T> void Bag<T>::add(T item) {     data[_size + 1] = item;     _size++; }  template <class T> void Bag<T>::print() {     for(int i = 0; i == _size; i++)         cout << data[i] << " "; }   here's CMakeLists.txt  cmake_minimum_required(VERSION 3.15) project(bag)  set(CMAKE_CXX_STANDARD 14)  add_executable(bag main.cpp Bag.cpp Bag.h)


Here is my MWE:  \documentclass[a4paper, 12pt]{report} \usepackage{amssymb, amscd} \begin{document}     \chapter{Test}      \begin{table}[h]         \center         \caption{Test}         \begin{tabular}{l | r}             Two & 2 \\             Four & 4         \end{tabular}     \end{table}      Test equation:     \begin{equation}         a+b=c^2     \end{equation} \end{document}   It produces this:    Now I would like to change equation numbering style. I want (1-1) instead of (1.1). How can I do that? Also, I want to preserve numbering style for tables and figures (Table 1.1:) , I don't want (Table 1-1:)


How to pass multiple dynamic ! -path arguments to find

I have a file which contains a list of directories/files that I want to ignore when searching using find. It looks like this:  .git .vim config .vimrc .bashrc   This list is not exhaustive and can have any number of items. How can I ignore these files/directories when using find.  I've been trying to do find . -type f ! -path ..., but haven't been able to pass dynamic list as argument.


Why is the prospective new kilogram standard a sphere?

I can understand the choice of material, silicon 28, but why is it a sphere rather than (say) a cube? Article   I would have thought that a sphere would have been the hardest shape to machine accurately.


Evaluating the limit $\lim_{n\to\infty}n\cdot \sin(2\pi e(n!))$

As I am beginner I don't have any idea about how to find limits, I want to find the limit as $n\rightarrow \infty$ of  $$\lim_{n\to\infty}n\cdot \sin(2\pi e(n!)) $$  please help.


How to vertically align cell in a longtable environment

Hi I want to vertically align my cells in a longtable. I also use \shortstack[l]. Don't know whether this has an effect. The Table looks like  \begin{landscape}  \begin{longtable}{|l|l|l|l|l|l|} \caption{A captuion \label{tab:atable}}\\ \shortstack[l]{\\A\\ B} & \shortstack[l]{\\C\\ D\\ E\\ F\\ G\\ H\\ I\\ J\\ K\\ L} & \shortstack[l]{M\\ N} & \shortstack[l]{\\O} & \shortstack[l]{\\P} & \shortstack[l]{\\Q}\\ \hline \end{longtable} \end{landscape}   I tried so may things, but the lext is still aligned at the bottom, not vertically.  Thanks!


Whenever I print a list of values in negative indexing in the console it shows only empty brackets. Whatever is the reason behind this problem  stu_information = ["name","roll_number","address","contact_information"] print(stu_information[-1:-2])  Output: []


80's SF TV show where people are underground and cans have generic labels like MEAT

Anyone remember an 80's possibly early 90's show, seemed like it would be post-apocalyptic show, where people are underground buying food.  The cans were all generic, white labels with black writing MEAT.  I can remember the kid asking the mom, what kind of meat?  I want to say the dad in the show looked like the dude from , the TV series, but I don't think it was V.


Is there a LINQ equivalent of string.Join(string, string[])

Is there any way to convert a collection of objects into a single new object using LINQ?  I want to use this within another LINQ to SQL expression.


How do you add thickness to a circle mesh?

I made a mesh circle now I want to add some thickness to it so it looks like a wire or string, not rope.


I'd like to switch to sans serif in order to make my text dyslexic-friendly.  Unfortunately, captions still have serif, and it raises a warning:  Font shape 'T1/lmss/m/sc' in size <12> not available Font shape 'T1/lmr/m/sc' tried instead   I (obviously) used lmodern, I tried \usepackage{anyfontsize} and several other tricks, but it won't work. Any idea?  \documentclass[a4paper,12pt]{report}        %article, report, book  \usepackage[latin1]{inputenc}            \usepackage[T1]{fontenc}                   \usepackage{textcomp}                                            \usepackage[gen]{eurosym}                                    \usepackage{gensymb}                             \usepackage[english,francais]{babel}     \usepackage{graphicx}                                            \usepackage{amsmath}                                             \usepackage{mathtools, bm} \usepackage{amssymb, bm} \usepackage[colorlinks=true]{hyperref}       \usepackage{nccrules}                                        \usepackage[version=3]{mhchem}                       \usepackage{pgf,tikz}                                    \usetikzlibrary{arrows}                              \usepackage{geometry}                        \usepackage{parskip}                                             \usepackage{lmodern}                                              \renewcommand{\familydefault}{\sfdefault}   % Supprime le serif (dyslexie) %\usepackage[font=sf, labelfont={sf}]{caption} %\usepackage[font=sf]{floatrow} \linespread{1.2}                                                     \geometry{hmargin=2.5cm,vmargin=2.5cm}       %\pagestyle{empty}                                       \hypersetup{urlcolor=blue,linkcolor=black,citecolor=black}  \begin{document}  \begin{figure}[h]     \centering         \includegraphics[width=0.7 \textwidth]{Deb.jpg}     \caption{Leviers}     \label{Leviers} \end{figure}


How is work done by friction in rolling without slipping zero?

When a body say a cylinder of radius R rolls down an inclined plane without slipping why is there no work done by the force of friction?  In other answers that I have read they say that it is because the displacement is zero but thats not true because the point on the bottom is moving on a trochoid. So this is not a duplicate.  We can also do a different approach like say initially the point P is in contact with ground where friction acts then the force of friction f provides torque about centre of mass equal to RfX where x is angular displacement net of P which clearly is not always zero in some cases might be .


How to windows 7 restore if error 0x8000ffff appears? Not able to boot into system

I have a computer with Windows 7. When I boot it, I get the usual starting animation, the harddisk LED blinks but then the screen gets black and nothing more happens. No sound, so activity, no changes when I press any keys or the mouse buttons.  When I start the computer with a Fedora 23 Linux live system from usb pendrive, it has no problems, everything works out of the box.  When I start the Windows system restore (I have testet several restore points), it takes some minutes with harddisk LED activity, but then an error appears: 0x8000ffff, and some text, that it is an unspecified error. Not helpful.  I am not very experienced with recent Windows systems, but very experienced with Linux and Mac OS X. So I need help here.  Now the question is: What is the best and fastest way to get the computer back to work with the old Windows 7 system? When I use the Windows 7 install CD, is there a way to install it over the old system? Could this work? Will the installed software work (or at least most of it)? I have not tested it, as I don’t want to destroy anything, until I know what the best approach is.


Do Indian passport holders need a transit visa at Frankfurt?

I'm an Indian citizen travelling back to India. On the way, I have a layover time of 8 hours at Frankfurt International Airport. Do I need a transit visa? I have an Indian passport and Brazilian tourist visa.


any more requests anymore requests  Are these two the same? It seems that "any more requests" is grammatically correct while "anymore requests" is not. Am I right? Why are they different?


Alternatives to jQuery for simple, backwards compatible, client-side website animations?

I was recently looking for an alternative JavaScript animation library, because for the few simple animations I wanted, a ~200kb jQuery library is not the best option.  After a bit of searching, I found , and implemented it successfully (and smoother) than the jQuery animation I had previously created. It weighs in at around 80kb - so still not perfect (but that's with additional plugins to be able to use CSS selectors, if you animate an SVG you can probably omit the 60kb required file).  I'm wondering if there are any other great options available.  Does anyone know of alternative libraries for animating elements with JavaScript?  The best options:   Do not rely on jQuery! Either does not rely on CSS3 Keyframes or has a fallback for when CSS3 Keyframes are not available (for backwards compatibility) Has minimal file-size and requires few or no other files to be included Is not too complicated to learn! (either good documentation, or familiar/simple syntax - I don't want to spend days constructing a simple animation)   I'm not interested in Flash at all.


automatic determination of the correct number of required clusters in text mining using R

I performed text clustering using k-mean method.  mydat=read.csv("C:/kr_csv.csv", sep=";",dec=",")    tw.corpus <- Corpus(VectorSource(mydat$name))   tw.corpus <- tm_map(tw.corpus, removePunctuation)   tw.corpus <- tm_map(tw.corpus, removeNumbers)   tw.corpus = tm_map(tw.corpus, content_transformer(tolower))   tw.corpus = tm_map(tw.corpus, stemDocument)    doc.m <- DocumentTermMatrix(tw.corpus)    dtm_tfxidf<-weightTfIdf(doc.m)  m<-as.matrix(dtm_tfxidf) rownames(m)<-1:nrow(m)  norm_eucl=function(m)   m/apply(m,1,function(x)sum(x^2)^.5) m_norm=norm_eucl(m) > dim(m_norm) [1] 399 860 res=kmeans(m_norm,3,30) clusters<-1:3 for (i in clusters){   cat("cluster", i,":", mydat[res$cluster==i,],"\n\n");   mydat[res$cluster==i] }   I manually set 3 clusters. Is it possible to automatically select the correct number of required clusters?


How to get monitor resolution and set it in DesktopLauncher config.width/height?

Help, i'm trying to make resolution like in Terraria on PC, when it is fullscreen but still windowed. Why this code won't work?  package com.imaginegames.mmgame.desktop;  import com.badlogic.gdx.Gdx; import com.badlogic.gdx.backends.lwjgl.LwjglApplication; import com.badlogic.gdx.backends.lwjgl.LwjglApplicationConfiguration; import com.imaginegames.mmgame.GameMain;  public class DesktopLauncher {     public static void main (String[] arg) {         LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();         config.foregroundFPS = 60;         config.title = "Millitary Madness";         config.width = Gdx.graphics.getWidth();         config.height = Gdx.graphics.getHeight();         new LwjglApplication(new GameMain(), config);     } }     It says:  Exception in thread "main" java.lang.NullPointerException     at com.imaginegames.mmgame.desktop.DesktopLauncher.main(DesktopLauncher.java:13)


'Whoever' or 'whomever' in a more complex sentence

I understand the difference between 'who' and 'whom', but in the following sentences I'm not sure whether to use 'whoever' or 'whomever':  'Give wh-ever did that a pay rise.' 'Tell wh-ever is teaching the class that I will be a little late.'  I look forward to reading your responses!


I have a dell E6230, installed Ubuntu 14.04 in VirtualBox. The display defaults to 600x400 showing the upper left corner of the screen. It's the only resolution that shows in the GUI.   How do I get it to a higher resolution?  The system has an Intel HD graphics 4000.


What is the group structure of 3-adic group of the cubes of units?

From what I understand about the group of units of the 3-adic integers, it consists all $a$ that can be expressed as a = $\sum_{i=0}^\infty a_i 3^i$ where $a_0 \neq 0$. How can we recognize which 3-adic integers are the cubes of units? I was also told that cubes of units of 3-adic integers form a group. What does this group look like?


Keeping food slow cooking for indefinite periods

Here's a weird question for the food safety enthusiasts on the forum.  I've just moved into a new apartment without a refrigerator. The landlord has promised to supply one in three weeks - and I don't feel like wasting money on a mini-fridge for such a short period of time.  However - I also don't particularly feel like subsisting on McDonalds until then, so I have thought of a possible solution and wanted to put it to the crowd to weigh in on whether it is safe.  Basically, I've been slow cooking vegetable soup and keeping it on 'low' in the crockpot until the dish has been eaten - then, I repeat the process.  I have done this 4 times already with successful results on each occasion: to my surprise, the dish was still tasty after 3 days, although I was initially nervous about eating something that had been cooking for so long.  I measured the temperature of the food and it remains about 70C the whole time.  So here's my question.  Is this a viable solution until my refrigerator arrives or is there something unsafe about cooking foods for such long periods? Is there an upper limit on how long food can be cooked for and stay good?  TIA for any responses!


What do I do when sites allow posting comments in answers?

I have been using Stack Overflow for many years now, and recently I started contributing. My filtered questions have: C, Objective-C, and Unix in them. I want to help some guys, so I click questions which are "unanswered"  The fact it: most of these questions were in fact already answered, but people posted a reply in comments, instead of "Answer" field.  Is there a solution for this? Is there a way to promote a reply to an answer?


Problem with editor formatting when using Edge Broswer

I have recently noticed a couple of problems when using the editor to re-edit an answer when using the Edge browser on Windows 10:   the editor is scrolled to the bottom of the text (as oppose to starting at the top), when you click the "Edit" link. I now see 3 blank lines are displayed for each blank line used for spacing in the original answer.   Using Edge the editor looks like this:    Using Firefox the editor looks like:    As you can see in the Edge browser the extra white space makes it hard to follow the flow of the answer. This is behaviour that I noticed only start to happen in the past week.  Does adding the "Bug" tag to this question mean someone from StackOverflow will look into it? Or is there some other place I should report this behaviour?


Remove all non digit characters by T-SQL

I use Sql-Server 2008 and have a table with phonenumer column by type NVARCHAR(20), in this table there is a lot of kind of data like the following  phone number ------------- 0913-876-9876 +941-9145678921 9176523461 915 986 23 45 ...   I am interesting to transfer this values to new table with correct format, in first step I need an script to remove all non digit characters for example I need a select script to above data returns me the following values :  phone number ------------- 09138769876 9419145678921 9176523461 9159862345 ...   Does any one have any idea about it?


I recently came across a question on Quora:     What are future plans for Gtk?   Is there plan for smartphone or tablet? Gnome focus on touch devices but Gtk software can not run on it?   On Quora, why Gtk topic only have 538 follower (Qt have 4k)?   I really worry about it :(     This is an interesting question, and I considered answering it. Unfortunately I have no idea why this is so...  So: Why did Canonical choose to use the Qt toolkit for Ubuntu Touch and not Gtk?  And why is it much less popular as a GUI toolkit?


Showing that $a$ is a primitive root modulo $p$

Let $p > 2$ be a prime number with the property that $ q:= \frac{p-1}{2} $ is also prime.  Let $a$ $ \in \mathbb{Z} $ with  $$a \not\equiv 0,-1( \text{ mod  }p )$$  How can I show that if   $$ a^{\frac{p-1}{2}} \not\equiv 1 ( \text{ mod } p ),$$ then $a $ is a primitive root modulo p ?  I don't get the right Idea to prove it..maybe you can help!  Thank you very much in advance!


Apparently, there is an advantage to having 6 legs in the insect world. What is that advantage, if anything? Why would such an advantage exist for insects, but not for other, larger land animals?  What do those middle legs do that the front and hind legs cannot, if anything? Are they really essential, or do they just generate more muscle power?


Newtonian Mechanics Thought Experiment Gone Wrong And Needs Clarification

I have been doing personal study in Classical Mechanics and reading Newton's Laws. While thinking about them I had a question I haven't been able to answer. It comes from the interactions of Newton's 1st and 3rd laws. First law  In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.  Third law  When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.  So here's the problem: An object is in a certain state (at rest or in motion with zero acceleration) and an external force is applied to that object. By the 1st Law the object should experience a change of state. But then by the 3rd Law a reactive force, of equal magnitude and opposite direction, would be applied on the object and now the sum of the forces would be zero (the object's state doesn't change at all). By this reasoning it would be impossible for an object to experience a state change because these forces would be in constant opposition. But objects do experience state changes so where is the mistake in this reasoning? Thank you for any help!


I tried to learn Algbraic Geometry through some texts, but by Commutative Algebra, I left the subject; many books give definitions and theorems in Commutative algebra, but do not explain why it is needed.  Can one suggest a good reference to learn this subject geometrically, which would also give ways to translate geometric ideas in algebraic manner, possibly through examples?  Particularly, I am interested in differentials on algebraic curves, Riemann-Roch theorem, various definitions of genus and their equivalences, and mainly groups related to complex algebraic curves such as group of automorphisms, monodromy group etc.


Index not created in pdf output, even though idx file is present

I have a document that has \usepackage{makeidx} and \makeindex in the preamble and \printindex inside the document body. An .idx file is created when I compile, no errors are signalled, still there is no index listing in the PDF document that is produced. There used to be one until all my files were deleted except the .tex file, after that I could not get the index to appear in my output. How can one troubleshoot this thing? I have changed all the "%bm" with "%tm" wherever I could find it in the build profiles (Tools -> Options -> Clean), as Thorsten Donig suggested on this website (in an answer to another posting regarding problems with the index creation). It did not solve my problem. I am using the TeXnicCenter editor on Windows XP, with the MiKTeX 2.9 distribution.


Our (and Luke's) original impression of Yoda is by no means flattering. He looks like a crazy hungry green thing that unfortunately has the ability to speak. Yoda digs through Luke's stuff, eats Luke's food, and, obsessed with that awesome little flashlight, ends up stealing it. (He even goes so far as to fight with Artoo over it.)  So was Yoda slowly losing it during all those years as a hermit?  Perhaps going from fighting battles and conversing with others on a daily basis to living in total isolation with no one to speak with would play a part in that? Or could Yoda have been faking his apparent insanity for some reason? (If so, what is mentioned reason?)


taking in subnet and ip address, performing a logical AND to retrieve the network address. My question is, how do I return a list of four octets, rather than just have all of the values stored into a list.  Example, my function is printing ['1','1','1','1'...], where as I want to print ['11111111','11111111','11111100','11111111']  def logicalAnd(ip, subnet):  test = list() for ipOctect, subnetOctect in zip(ip, subnet):     for i,j in zip(ipOctect, subnetOctect):         octet = (i and j)         test.append(octet) print(test)


Question about self-complementary graphs

Question Prove that for every integer k≥1, exists a self-complementary graph with 4k vertices half of which are of degree 2k-1 and the other half of degree 2k.  My approach So, I think the easiest way to prove what is asked is by induction. I can prove the base case for k=1, but as far as the inductive step is concerned, I cannot seem to reach a conclusion as to why if the statement holds for n, then it holds for n+1.  Any help would be appreciated.


Why is a monoid with right identity and left inverse not necessarily a group?

This problem is from Herstein's 'Topics in Algebra'. I've thought about it a bit but haven't come up with much.  Let $G$ be a non-empty set with an associative product which also satisfies:   $\exists e\in G $ such that $\forall a \in G$, $a \cdot e=a$. Given $a \in G$, $\exists y(a) \in G$, such that $y(a) \cdot a =e$.   Prove that $G$ need not be a group.  I know that $G$ is a group if any one of those multiplications is switched around, i.e, either $a \cdot y(a)=e$ or $e \cdot a=a$. But I can't quite understand why in this case $G$ is not a group. I'd be much obliged if someone can give me a good explanation of why it must be and I'd also appreciate a counter-case if nothing else.   Thanks a lot. Cheers!


Handling ranges where the unit prefixes the number

If the unit follows the number, then according to the accepted answer of the  , you can skip the unit for the first value, such as "1–5 ℥".  However, that question, and the section of the source cited in the accepted answer, doesn't describe what should happen if the unit prefixes the number. Should it be     Jeans cost $10-100   or     Jeans cost 10-$100   or is only     Jeans cost $10-$100.   acceptable?


I have read and understood that a normal force has got nothing to do with torque on a physical pendulum. But I can't understand in which direction the normal force points to. Can someone help?   is confusing me. Please help.  This image. Can you explain the direction of normal force in it?


Book about human colonization of a planet without rain, youngest member names the planet and later narrates the story to children

During my elementary years, I remember a book about a group of humans venturing off of Earth to colonize a new planet. One of the things I specifically remember is how they had the youngest member of the colonization team name the planet. Another thing I remember is how the planet did not have rain, rather having lots of dew in the mornings. The book ended with who I believe to be the youngest member (who named the planet) telling the story of the colonization to the new generation of children.


How does delete[] know how much memory to delete?

int* i = new int[4]; delete[] i;    While we call delete[], how does the program know "i" is 4 byte-length. Is 4 be stored in somewhere in memory? The implementation of delete[] depend on System or Compilers? Is there some System API to get the length of i?   As HadeS said, which will hold the information how much memory has been allocated? And where? It must be hold in memory, or maybe nearby the pointer i.


I have a friend who acts horribly mean to people but whenever he needs something from the person he has been mean to, it is like he becomes another person. He acts extremely nice.However, even if he does get the thing he wants he instantly goes back to being mean. I have been trying to find a word that describes this person but I can't seem to find it. Any ideas?


Trying to configure a HD 7470/8470 - Strange video refresh Title changeg and instability of video card

I've found .  New items are in my comments ....  I have got amd-driver-installer-catalyst-15-20.1046-x86.x86_64.run in my Downloads folder ready to run, but when I'm trying to issue the command sh amd-driver-installer-catalyst-13-4-x86.x86_64.run --buildpkg Ubuntu/trusty, it does not want to run it. I have the error message:  sh: 0: Can't open amd-driver-installer-catalyst-15-20.1046-x86.x86_64.run   Can someone explain me what to do?


I have a Toshiba laptop running Window XP (32) about 10 or 12 years old.  It is used at a model railroad club and its sole function is to run Java and an open source program called Decoder Pro.  It works great for our purposes but is getting dated as it no longer accepts updates.  I would like to use Ubuntu.  Which version should I use, etc.?


Why does Linux's UEFI entry disappear at each boot?

On an Acer PC, after installing any Linux system with any bootloader, I can boot it once, but after a reboot the UEFI Linux entry is gone.  The Linux system's file in the EFI boot partition seems to still be here.  I tried this with Ubuntu and ArchLinux, with GRUB and systemd-boot.  Why does this entry disappear simply by booting the system ?


It is acceptable to end these sentences with prepositions?

I've heard some talk about ending sentences with prepositions. It seems like the overall consensus is that it is indeed okay.  But, I have come up with a few examples. I am wondering if it is "necessary" or just a choice of style here.   'Whom will you go to the party with'?  or   'With whom will you go to the party?'  Now, because of the sentence construction, you can put with before the whom. But do you need to do this? Is it acceptable to say "Whom will you go to the party with?'  Another example is when you use "which" with prepositions, where you have an option to put the preposition before which. (For which event are you preparing? vs. Which event are you preparing for?)  Is this just a matter of style or choice? Also, is there a more recommended option in formal writing?  As a separate question, is it also a "myth" that you can't use a split infinitive, especially in formal writing?


In the Voyager episode , we learn that Tuvok was once a junior science officer aboard Sulu's Excelsior, and that he had been present at the moment of death of Lt. Cmdr. Dmitri Valtane during the events of Star Trek VI: The Undiscovered Country.    If we follow the events as they were presented in "Flashback", then Valtane would have died well before the Excelsior arrived at Khitomer to aid Kirk's Enterprise in the film's climactic battle.  However, at the end of The Undiscovered Country, we see Valtane alive and well on the Enterprise viewscreen (he is the leftmost officer, with the goatee):    In-universe, what is the truth regarding Dmitri Valtane?  Did he survive the events of Star Trek VI or did he perish on the bridge of the Excelsior, only to appear as some kind of...Force ghost?


Apologise if this question isn't relevant to this forum, I tried my best to look for similar questions but couldn't find one.  I am a computer science major enrolled in a not-so-renowned university in India.  I am in my pre-final year and have taken four math courses. While I did well in the first two (got an O grade i.e the highest grade possible), due to some personal problems, I got a D and a C in the next two courses. Unfortunately, my university does not have a provision to retake the courses.  My eventual plan is to apply for grad school in fields such as machine learning where they require a strong math background.  My question is: how can I show that I know the required math for the courses beyond my uni courses?  One way I thought was of doing MOOCs on the subjects and uploading my solutions to them somewhere? But the general consensus which I found here was that MOOCs don't hold much value when it comes to showing proficiency in a subject.  What are some other ways in which I can demonstrate my proficiency in the subject?   Thank you.  EDIT: The courses where I fared poorly included the following topics (since it's an engineering course, we don't have specific courses like Linear Algebra or Statistics - we instead learn an overview of mixture of a few math subjects each semester) - Fourier Analysis, Laplace Transform, Vector Algebra, Complex Variable and Mapping, Z-transform, Complex Integration, Matrices, Probability, Sampling Theory and Mathematical Programming.)


How to horizontally center divs with auto widths when using inner elements as display: block?

I have something like this:  [ [span][link]              ]   but I would like something like this:  [       [span][link]        ]   Where the  and  element inside
 element are centered in the middle horizontally  span and a element have auto width  div has hardcoded width 250px  How to do that?  My current CSS code is not working, it's centered to the left ;(:  a {     margin: 0px;      padding: 0px;     display: block;     float: left;     width: auto; }  span {     float: left; }  div {     display: inline;     text-align: center;     margin-left: auto;     margin-right: auto;     width: 200px; }   and HTML:
    Name    Link


Cyclic group with exactly 3 subgroups: itself $\{e\}$ and one of order $7$. Isn't this impossible?

Suppose a cyclic group has exactly three subgroups: $G$ itself, $\{e\}$, and a subgroup of order $7$. What is $|G|$? What can you say if $7$ is replaced with $p$ where $p$ is a prime?   Well, I see a contradiction: the order should be $7$, but that is only possible if there are only two subgroups. Isn't it impossible to have three subgroups that fit this description?  If G is cyclic of order n, then $\frac{n}{k} = 7$. But if there are only three subgroups, and one is of order 1, then 7 is the only factor of n, and $n = 7$. But then there are only two subgroups.  Is this like a trick question?  edit: nevermind. The order is $7^2$ right?


I've leart in Calculus 1 that the derivetive of $f(x)$ is:  $$\lim_{h\to0} \frac{f(x+h) - f(x)}{h}$$.  suppose $f(x,y)$ is a function with 2 variables,  does $$f'(x,y) = \lim_{h\to0} \frac{f(x+h, y+h) - f(x,y)}{h}$$ ?  If not , what is the derivetive of function with 2 variables?


Why can't light escape from a classical black hole?

Photons do not have (rest) mass (that's why they can move at speed of "light").   So, my question is how the gravity of classical$^1$ black hole can stop light from escaping?  --  $^1$ We ignore quantum mechanical effects, such as, Hawking radiation.


Where is the ideal place to load javascripts in html?

I understand inline javascripts scattered through html code like the following example is bad  <html>   <head>   </head>   <body>      <p> Foo <script></script></p>   </body> </html>   However, after coding for a while, understanding that loading Javascripts at the end of the document is the best way to go. I do see a lot of the sites that conform to loading scripts at the end of their document, do so in the following manner :  <html>   <head>   </head>   <body>      <p> Foo </p>      <script></script>   </body> </html>   What is not made clear, is why not :  <html>   <head>   </head>   <body>      <p> Foo </p>   </body>   <script></script> </html>   .. as this is outside the body tag which means that the body (in theory) can process faster and still load your scripts before finalizing on </html>.  Or even this :  <html>   <head>   </head>   <body>      <p> Foo </p>   </body> </html> <script></script>   Each variation will have (in theory) different performance results, and/or may break functionality in the page depending on the script contents of course.  Of the above formats, which one is the ideal place to load javascripts that would have the highest performance gain without breaking html ?


Search comments by commentator's user-id

Often I find comments showing the commentator is quite knowledgeable and able to express concepts in a poignant way, and I would like to discover more comments by such a user (in a similar way one could do i.e. on Reddit, YCombinator, etc.).  Is it possible to search comments by commentator's userid on Stack Exchange?  If not, may I suggest it as a feature request?


Why emails sent by my server to outlook/hotmail are still being seen as spam?

I know that this kind of question has already been asked but I've spent hours trying to solve the problem without any change. All the emails I send using PHPMailer are being seen as spam by hotmail/outlook accounts. I don't have this problem with gmail or yahoo. But outlook seems to be very very strict...  My website is stored on a Ex2 Hosting shared server. Using  I don't see any sign that the server might be blacklisted.  Both DKIM and SPF authentification are activated. And there are unsubscribe-links in both header and html/body part.  When I make a test with  the only problem detected by SpamAssassin is 'MISSING DATE'. Even if I set current date in header (see code below).  Many thanks in advance for anyone trying to help me :)  Here is my code :       date_default_timezone_set('Europe/Paris'); $dt = new Datetime('now');       $mail = new PHPMailer(true);      try {          $mail->SMTPDebug = 0;         $mail->isSMTP();         $mail->Host = 'my.shared-server.com';         $mail->SMTPAuth = true;         $mail->Username = 'contact@myfirm.com';         $mail->Password = 'MYPASSWORD';         $mail->SMTPSecure = 'tls';         $mail->Port = 587;         $mail->ReturnPath = 'contact@myfirm.com';         $mail->setFrom('contact@myfirm.com', 'My Firm');         $mail->addAddress($recipient, '');         $mail->addReplyTo('contact@myfirm.com', 'My Firm');         $mail->addCustomHeader('List-Unsubscribe', '<mailto:postmaster@myfirm.com?subject=Unsubscribe>, <https://www.myfirm.com/unsubscribe>');         $mail->MessageDate = $dt->format('Y-m-d H:i:s T');         $mail->CharSet = 'UTF-8';         $mail->isHTML(true);         $mail->Subject = $title;         $mail->Body    = '<!DOCTYPE html>                 <html>                     <head>                         <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">                         <style>                             /* css code */                         </style>                         <title>My Firm</title>                         <meta name="description" content="An email from My Firm">                         <link href="https://fonts.googleapis.com/css?family=Raleway:200,300,400,500,600,700,800" rel="stylesheet">                     </head>                     <body>                         <p>$message_html</p>                     </body>                 </html>';         $mail->AltBody = $message_text;          $mail->send();          echo 'Message has been sent';      } catch (Exception $e) {          echo 'Error';      }


Suppose that $G$ is an infinite group and $H\le G$. The criterion for normal subgroups states that if $H^g\le H$ for all $g\in G$, then $H\trianglelefteq G$ (and thus $H^g=H$ for all $g\in G$).  I am looking for an example of an infinite group such that $H^g\le H$ for some individual $g\in G$, but $H^g\ne H$.  I know that abelian groups are excluded, since each subgroup of such a group is normal.   Thanks.


Why all the dismissal for Circular Reasoning?

In my studies of Mathematics and (mostly) Theoretical Computer Science I've encountered what is known as  which purports to demonstrate nothing can be actually be proved because all proofs are one of the following:   The circular argument, in which the proof of some proposition is supported only by that proposition The regressive argument, in which each proof requires a further proof, ad infinitum The axiomatic argument, which rests on accepted precepts which are merely asserted rather than defended   My response: What's wrong with circular reasoning in the first place? I simply disagree fundamentally with the notion that we can't have "closed systems" of knowledge. Why is there this idea that we need some kickstarter axioms to prevent going around in circles?  It's not that I don't appreciate the need for axioms from a convenience perspective. It's that I don't think that there's really no merit to going around in circles in the first place! "I am God therefore I am God" is valid. Things don't need to make sense. After all sense is not an inherent property of a statement. It requires interpretation to judge that. Interpretation from another language - in the form of symbolic manipulation. It's all inherently meaningless - so why bother with making sense when you can just be valid. This is my argument for why circular reasoning is a blessing. Instead of hunting down possibly ad infinitum the "source", the most "fundamental" axiom, the "point", we can prevent the existence of the Hydra altogether. It's either circular reasoning, or the same thing in disguise but with more stress on top of it - the difference is that in the latter the circle never runs out. Why choose stress?


Can we observe something on just the horizon of a black hole?

It is not clear to me if we can observe matter infalling to a black hole. When it is stated that time stretch to infinite for an external observer, then we should see a kind of accretion or jam at the very border. Like two  compenetrating objects at the same place. I hope this is naive.  To be precise: think of the crash test  mannequin that divulgative science often send to a black hole. Ignore spaghettification. Do we really see that mannequin "frozen"  and never passes throughout the horizon?  If so, what happen to a second mannequin if it happens to it to fall at the same spot?  Or there is no the same spot as for the infalling matter has already shifted the horizon?   May be the mannequin is not the best testing particle. Feel free to replace mannequin with atoms or particles and so forth. I have been pictorial for sake of clarity.   Edit: the opening sentence refers to direct observation. Not to the observing of radiation due to the acceleration towards the black hole like that emitted by a hot accretion disk.


What does Bell's Theorem really violate?

Well this is a fairly straightforward question. I know it states that either hidden variables is wrong or Quantum Mechanics. But indirectly hidden variables is a part of QM due to uncertainty. So what exactly does it violate. I am just a bit confused.


disable ssh login but maintaining scp function for a user

how to create a user on a linux box where it - can be used for scp from the remote system - can't be used for ssh login from the remote system  Thanks in advance


I am using the \usepackage[nottoc,notlot,notlof]{tocbibind} to import my Bibliography. However, I would like to change the name, both in the ToC and the header, I have tried to use commands such as \renewcommand{\bibname}{header} and \renewcommand{\refname}{header} but without success. I'm using babel with English if that matters.


Setting value to static variable returns error

I basically try to save the current state of mRecyclerView into a static Parcelable variable to keep it safe onPause and restore it to the mRcyclerView onResume.  Here is my static variable's class:  public class MySavedState { private static MySavedState ourInstance = new MySavedState();  private Parcelable state;  static MySavedState getInstance() {     if(ourInstance == null){         ourInstance = new MySavedState();     }     return ourInstance; }  private MySavedState() { }  public Parcelable getState() {     return state; }  public void setState(Parcelable state) {     this.state = state; }   }  And here is the line where I try to set a value:  @Override public void onPause() {     super.onPause();      Parcelable newState = mRecyclerView.onSaveInstanceState();     state.setState(newState);   }   And the error message:  java.lang.RuntimeException: Unable to pause activity {com.gunaya.tasmaew/com.gunaya.tasmaew.Controller.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.gunaya.tasmaew.Model.MySavedState.setState(android.os.Parcelable)' on a null object reference                   at android.app.ActivityThread.performPauseActivity(ActivityThread.java:3745)                   at android.app.ActivityThread.performPauseActivity(ActivityThread.java:3704)                   at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:3679)                   at android.app.ActivityThread.access$1100(ActivityThread.java:177)                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)                   at android.os.Handler.dispatchMessage(Handler.java:102)                   at android.os.Looper.loop(Looper.java:145)                   at android.app.ActivityThread.main(ActivityThread.java:5951)                   at java.lang.reflect.Method.invoke(Native Method)                   at java.lang.reflect.Method.invoke(Method.java:372)                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.gunaya.tasmaew.Model.MySavedState.setState(android.os.Parcelable)' on a null object reference                   at com.gunaya.tasmaew.Controller.mListFragment.onPause(mListFragment.java:117)   And as an extra question, i keep having this error message in my debugger:  ((Bundle)parce).mClassLoader = Cannot find local variable 'parce'   Thank you very much for your time guys.


Making Linearly Independent Set into Basis

Suppose that $V$ is an n-dimensional vector space over a field $F$ and $\{\vec{v_1}, ...,\vec{v_m}\}$ is a linearly independent set in $V$. How do I show that $m \leq n$ and $\exists \{\vec{v_{m+1}},...\vec{v_n}\} $ such that $\{\vec{v_1}, ...,\vec{v_m},\vec{v_{m+1}},...\vec{v_n}\}$ is a basis for $V$?   The book I'm using gives a hint involving using the basis for $V$ and creating the set of vectors composed of $\{\vec{v_1}, ...,\vec{v_m}\}$ and the basis of $V$, but i don't really understand what it is asking with that.


I'm struggling with some concepts in my algebra class. I've chosen these two completely unrelated examples that demonstrate my struggling topics (characteristics and function rings) the two are the following:  $1$) Let $X$ be a set, and let $S$ be a ring. Give a proof that the left distributive law holds for $(S^X, +, *)$.  $2$) Suppose $Y^3 = Y$ for each element $Y$ of a unital ring $R$. Show that $R$ has a finite characteristic d that is a divisor of $6$.  Any example solutions for these proofs would be helpful. Thank you.


How can I search for packages depending on a exact package?

I'm experimenting a bit with aptitude search terms and finally discovered how to do search on dependencies, which is:  aptitude search '?depends("searchterm")'   The only problem that I've found is... that the "searchterm" uses expansions. If I use aptitude search '?depends("vim")' it will look for any packages that depends on a package that contains the word vim in the start, middle or end. Is there a way that I can match the exact package called vim and no other expansion?


Moderator flag notifications should reach mobile

I spend a great deal of time surfing SE sites from my phone during commutes and other down times. The global inbox is quite effective at reaching me even for chat pings. Quite frankly the mobile site is very well done!  However as a community moderator, there is a whole class of information not getting through. There are no notifications for moderator flags! I can switch to the full site and see these but that is inconvenient for browsing, so I only end up checking for flags periodically.  Ideally the moderator tools should all be available in mobile templates, but as a stand-by it's reasonable to switch to the full view to handle flags, but flags would get addressed in a much more timely manner if I knew about them. As it stands I often come and go from the site without even knowing there are outstanding flags.  A simple flag counter added to the header next to the notification counter and linked to the tools page (which automatically opens the full version anyway right now) would fix this.


I am using a Gigabyte motherboard. Today my screen suddenly went black and the beep sound began. I tried to restart my PC, but when it tried to boot into Windows, the same beep sound appear again. I had to totally power off the PC and start it again to get it to run properly.  I am curious about the beep sound and want to know why my PC crashed. The beep code is a repeating, long beep code. Something like "BEEEEEEEEEEEEP ........ BEEEEEEEEEEEEP  ........ BEEEEEEEEEEEEP".  I tried online search, but I can't find my beep code. Do you know what it means?  Thank you.


My materials section is different than the one shown on tutorial

My materials section (the bottom one) is far different from what  the top section looks like. I need help in how i could change it to look like that.


Issue with setting default Value for DateTime

I have a model in which I can not set [DefaultValue] for DateTime, the object is used to generate a list of users from the powershella script. When I do not have default value and powershell return null this causes an error. I would like to make the date set to 01.01.1990 00:00:00 in the case of null  public class user         {             [DefaultValue("")]             public string Name { get; set; }              //[DefaultValue( )]             public DateTime PasswordLastSet { get; set; }         }


Variable won't print out to console when using scanners

Here's the code:  import java.util.Scanner;  public class Hallo {  public static void main(String[] args) {      System.out.println("What is your name?");      Scanner firstScanner = new Scanner(System.in);      String imput = firstScanner.nextLine();      if (imput.length() > 6 ) {          System.out.println("That's quite a long name!");      }      else {          System.out.println("A nice and consise name you have.");     }      imput = firstScanner.nextLine();      if (imput == "Thank you") {          System.out.println("Yes, so how many siblings do you have?");      }      else {          System.out.print("Aren't you suppose to say 'Thank you' when someone complements you?");      }   }   }  When I type, "Thank you" in the console, it still says "Aren't you suppose to say 'Thank you' when someone complements you?" even though I typed it exactly as I declared it. Why won't it ask me how many siblings I have?  Sorry if that was hard to understand.


Which directories does angle brackets  search in C/C++ on mac?

I am trying to build a software using make launch and it is failing because its header files can't locate particular file. I do have the file but I don't know where to put it on my Mac such that the header files would be able to locate it using angled brackets <>.  Thanks


I'm trying to design a package so that I can 'theme' a document quickly. I've done this, but as a sort of academic exercise I'm trying to design an option compact that adjusts margins, title, and layout to optimize the document for use of multicols.  The issue here is I want to use geometry to define the margins, but do not want to load thegeometry package otherwise. I have a little bit of a workaround by using \PassOptionsToPackage, but then the package is loaded even when the option is not selected and it changes LaTeX's default margins which I don't want to change in this default mode. Ideally, the textpos and multicol packages wouldn't be loaded unless the option is selected either, because they are otherwise unnecessary.  What is the most correct way of accomplishing this?    The custom package:  \NeedsTeXFormat{LaTeX2e}[1994/06/01]  \RequirePackage{graphics} \RequirePackage{tikz} \RequirePackage{libertine}  \pagestyle{empty} \setlength{\parskip}{6pt plus 2pt minus 2pt}  \newcommand{\fullline}{%     \noindent\rule{\linewidth}{.4pt}\\     \vspace{-\baselineskip}\\ }  \newcommand{\stretchtitle}[1]{     \vspace*{-5\baselineskip}\noindent\hspace*{-.75in}     \resizebox{\dimexpr1.25in+\linewidth}{!}{\textsc{#1}}     \vspace{\baselineskip}\\ }  \newcommand{\header}[1]{%     \noindent{\sf\huge\\\\\noindent%     \begin{tikzpicture}[remember picture, overlay]%         \draw[right] (-.4em,.5em) node {#1};%         \draw[line width=1pt] (-.4em,-2em) -- (-.4em,0em) -- (\dimexpr.4em+\linewidth, 0);%     \end{tikzpicture}}\vspace{-1.25\baselineskip}\\\par\noindent% }  \newcommand{\leveltwo}[1]{%     \vspace{\baselineskip}\noindent{\Large\sf#1\normalsize\\\rule{.5\linewidth}{1pt}} }  \RequirePackage[absolute]{textpos} \RequirePackage{multicol}  \DeclareOption{compact}{     \PassOptionsToPackage{margin=.62in}{geometry}     \setlength{\columnsep}{18pt}     \setlength{\TPHorizModule}{\paperwidth}     \setlength{\TPVertModule}{\paperheight}     \renewcommand{\stretchtitle}[1]{         \newcommand{\titlewidth}{3.37in}         \begin{textblock}{.88235294}(0.058823,0.045454545)             \noindent             \resizebox{\titlewidth}{!}{\Huge{\textsc{#1}}}\\             \rule{\textwidth}{1pt}             \normalsize         \end{textblock}          \vspace*{.5in}     } } \ProcessOptions\relax  \RequirePackage{geometry}   MWE for custom package use:  \documentclass[letterpaper]{article} \usepackage{heavymodern} \usepackage{lipsum}  \begin{document}     \stretchtitle{Minimum Working Example}      \header{Example}%     \lipsum[1]      \leveltwo{Second-Level Example}      \lipsum[2] \end{document}


Why is $\mathbb{R}^2$ not a subspace of $\mathbb{R}^3$?

I cannot understand why $\mathbb{R}^2$ is not a subspace of $\mathbb{R}^3$.   My reasoning is as follows: Choose any elements $v_1$ and $v_2$ from $\mathbb{R}^2$, add them together you get an element of $\mathbb{R}^2$ and same for scalar multiplication and $0$ vector is an element of $\mathbb{R}^2$. So where did I go wrong?


Incorrect reference when combining amsmath, hyperref, and \tag

In the following MWE, I receive a warning and a reference points to the wrong element.  \documentclass{article} \usepackage{hyperref} \usepackage{amsmath} \begin{document}     \begin{equation}         \label{eq1}     \end{equation}      \begin{equation}\tag{\ref*{eq1}b}         \label{eq1b}     \end{equation}      \begin{equation}         \label{eq2}     \end{equation}  This reference is incorrect: \ref{eq2} points to 1b. Also, this warnings appear: \begin{verbatim}         pdfTeX warning (ext4): destination with the same identifier         (name{equation.0.2}) has been already used, duplicate ignored     \end{verbatim} \end{document}   In this variant with equation*, the latter problem is fixed, but a new one introduced. A link that was fine before is now wrong:  \documentclass{article} \usepackage{hyperref} \usepackage{amsmath} \begin{document}     \begin{equation}         \label{eq1}     \end{equation}      \begin{equation*}\tag{\ref*{eq1}b}         \label{eq1b}     \end{equation*}      \begin{equation}         \label{eq2}     \end{equation}      This reference is incorrect: \ref{eq1b} points to 1. No warning. \end{document}   How can I get all references correct?  These questions are similar, but don't help:


Distributivity of quantifiers over logical connectives

I'm given the following expresssion: $$ \forall a [\phi(a) \to \psi(a)] \wedge \forall a [\psi(a) \to \phi(a)] $$ that I wish to logically reduce to: $$ \forall a [\phi(a) \leftrightarrow \psi(a)] $$  The only area I'm uncertain about is showing that universal quantification is distributive over conjunction, as trivial as it seems. Rather, I'm not sure where to find theorems or lemmas related to the topic.  The set theory text from which this comes provides no insight and the introductory logic text I own also doesn't touch on the matter, at least in any great detail.


Why should one use "back" in these examples?

Back at home, it was so dim.      I used to play football back in my school days.      We used to eat by hands back in my country.   Is back optional in these sentences or does it change their respective meanings in any way?


Need more help with SEDE (Trying to grab a random result)

I have been working on getting the Id of a random non closed question and came up with this:  Select Id from posts where ClosedDate IS NULL ORDER BY RAND()    For some reason I get the same results every time. Is this a bug or am I just doing this wrong?


Geometric intuition of improper integrals

I am aware that the area under the curve of $\frac{1}{x}$ is infinite yet the area under the curve of $\frac{1}{x^2}$ is finite.   Calculus and series wise, I understand what is going on, but I can't seem to get a good geometric intuition of the problem. Both curves can be shown to converge to $0$ (the curves themselves, not the area), and on the interval from $1$ to infinity, the two curves have nothing intrinsically different. Can someone please provide me with an good geometric intuition of what's going on? I can't find anything on the web, people seem to not want to explain it geometrically.


What does the "Bitmap Caching" option do in the Remote Desktop Client?

This setting has always confused me:    What exactly does the Bitmap Caching option in the Windows Remote Desktop Client do?  I understand that it is supposed to improve connection performance, but how?  Is it really that much of a difference?


Does this example prove that an infinite causal regress is impossible?

Let's suppose that a soldier wants to shoot a bullet, but in order to so he must receive an order from his superior, and his superior must himself receive the order from his superior .... if this chain goes to infinity, the first soldier will never shoot a bullet.  So does that mean that an infinite regress of causes is impossible ?


popout a mac mail window from full screen / split view

I run my mac mail in split view with other programs on a side monitor. Sometimes it would be nice to pop out reply windows and individual emails from full screen / split view so I can bring them to my main monitor.  Is there anyway to do this without undocking the mail program all together?


I have a response from an AJAX request and depending upon the situation that calls it, I want to either replace the data on the screen, or append new data to the screen.   Two possibilities are as followed:  $('#data').append(response); $('#data').html(response);   I tried to do something like:  var action = "append" $('#data').(action)(response)   That didn't work, how can I do this?


could somebody explain this longer way? I don't really understand that part of code, how it works. Could somebody write it out long way like:     if thing = "x"    if thing = ...  thing = "x" if thing.lower() == "o" else "o"


If I link to clean URLs based on the page title but redirect to URLS with ids as part of a site migration, is that bad for SEO?

I'm importing stuff from a Drupal site that has a couple of alias URLs:  /node/123 /my-alias-node-title   My new site is a very simple CMS handmade in PHP by me as a practice.  In the new system, the URL for each page has this format:  /contenido.php?id=30   I've managed to rewrite all traffic to a PHP file (reenvio.php) using a rewrite rule:  My .htaccess file is like this:  Options +FollowSymLinks RewriteEngine On RewriteCond %{SCRIPT_FILENAME} !-d RewriteCond %{SCRIPT_FILENAME} !-f RewriteRule ^.*$ ./reenvio.php   My PHP file consults the database and do the redirects. So, when users type /node/123 they get redirected to /contenido.php?id=30  Is that a problem from an SEO perspective? My pages will still link to URLs like /my-alias-node-title but my users will end up seeing /contenido.php?id=30   Is there any way to address this issue in a different, better way? Because after all, the user still sees the ugly URL, so I assume Google sees it as well.


Finite group with cyclic Sylow-2 group has a normal subgroup of index 2.

I'm working on the following qual problem and I'm not sure how to do parts b and c.    a) This uses a nifty argument with considering the map $N_G(S) \to \operatorname{Aut}(S)$ via conjugation. And using the fact that $|N_G(S)/C_G(S)|$ is odd, and divides the order of $\operatorname{Aut}(S)$ so it must be 1.  b) Not sure how to proceed after the hint.  I think we're supposed to use strong Cayley's theorem here by saying that the kernel of this homomorphism is the largest normal subgroup of $G$ contained in $S$.  c) No idea how to do this one, but I was thinking if we can show the subgroup has order n(from part b) then we note that $|N||S| = |G|$ and so $NS = G$.


How to calculate Area Under the Curve (AUC), or the c-statistic, by hand

I am interested in calculating area under the curve (AUC), or the c-statistic, by hand for a binary logistic regression model.  For example, in the validation dataset, I have the true value for the dependent variable, retention (1 = retained; 0 = not retained), as well as a predicted retention status for each observation generated by my regression analysis using a model that was built using the training set (this will range from 0 to 1).  My initial thoughts were to identify the "correct" number of model classifications and simply divide the number of "correct" observations by the number of total observations to calculate the c-statistic. By "correct", if the true retention status of an observation = 1 and the predicted retention status is > 0.5 then that is a "correct" classification. Additionally, if the true retention status of an observation = 0 and the predicted retention status is < 0.5 then that is also a "correct" classification. I assume a "tie" would occur when the predicted value = 0.5, but that phenomenon does not occur in my validation dataset. On the other hand, "incorrect" classifications would be if the true retention status of an observation = 1 and the predicted retention status is < 0.5 or if the true retention status for an outcome = 0 and the predicted retention status is > 0.5. I am aware of TP, FP, FN, TN, but not aware of how to calculate the c-statistic given this information.


How to create executable of LISP program

I want to compile LISP file (e.g. main.lisp) and create an executable (main.exe).  (write-line "Hello World") (write-line "I am at 'Tutorials Point'! Learning LISP")   How to execute the LISP file so that it create an exe.  Actually, I didn't get clear answer from . I need a command or step by step flow to create an exe.


To open several files in separate tabs in vim I need to execute command   vim -p file1 file2   I fave directory that contains many files and I would like to open all files with extension c in vim editor.  How to make this in short and elegant way?


I have upgraded to 16.04 LTS from 14.04 as advised by Updater on 28 July 2016  The problem is:  The software, DigiKam did not install. It is not installed from Ubuntu Software also.  I have tried with using the Terminal with the following commands:348196  sudo apt-get update sudo apt-get install digikam 348196 blackie@BLACKIE-ITX001:~$ sudo apt-get install digikam Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies.  digikam : Depends: digikam-data (= 4:4.12.0-0ubuntu7) but 4:4.14.0-trusty~ppa1kde414 is to be installed348196            Recommends: kipi-plugins but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Querry:   How do I rectify this?


not able to hear voice in YouTube videos

I am not able to hear the voice in my YouTube videos, but I can hear the music in the video and my head phones work perfectly with other sort of videos and i can perfectly hear songs also and the problem is with all video on YouTube. so suggest me some remedy please.


how long will it take from airplane just arrived in Geneva airport to the train which is in train station in same building?

I will arrive to Geneva airport from Paris, the specified arrival time is 09:05 in the morning. I heard that the airport terminal and train station are in same floor there, I have to transfer to the train to Interlaken right away and can I make it to the 10:00 train after all the luggage claim and sort of security pat down things? if that 55 minutes are too much pushing how much time will be the best?


How do creatures moving on the same initiative handle the effects of Sleep and Hypnotic Pattern?

Imagine a small group of goblins moving on the same initiative that are hit by hypnotic pattern.  When one goblin that was not affected uses its action (or an attack) to wake its ally that failed the save, can that awoken ally in turn wake another affected ally, effectively ending the spell with a chain of actions in a single turn?  Or, instead, is only one goblin able to be woken up that turn, with the waking goblin having no action to use on the next sleeping  ally?


Why does Buckbeak's executioner use an axe?

I've only just identified something which has been bugging me for literally years. Why does the executioner Fudge brings to kill Buckbeak use an axe? Seriously, one Avada Kedavra and it's done with zero pain, zero mess and zero effort. Possible arguments and why I think they're wrong.  Not every wizard knows how to use the killing curse. - Sure, that's true but we know the Ministry of Magic employs aurors, and employs someone purely to execute dangerous animals. So that wouldn't be a problem. It's an unforgivable curse, it's illegal. - The fake Professor Moody makes it clear that the unforgivable curses are only illegal when used against a fellow human being, then uses them on spiders by way of demonstration.  Here are some possible real-world, fiction writing, reasons (I'm not looking for these):  The image of an executioner with an axe is a frightening and dramatic image. The sound of the axe coming down gives the kids a reason to falsely think Buckbeak has already been killed. This might make it easier for Harry and Hermione to escape with Buckbeak.  So, are there any in-world reasons the ministry would choose to use an axe instead of a spell?


For a frame of reference, I'm an undergraduate in mathematics who has taken the introductory analysis series and the graduate level algebra sequence at my university.   In my analysis class, our book lists axioms describing the structure of the reals. This seemed unnatural to me, as we can often write definitions or lists of rules that no set actually satisfies. So the axiomatic approach doesn't reassure me that the thing we are discussing can actually exist.  Our teacher talked to us about dedekind cuts as a way of explicitly constructing reals, which seemed more useful to me.  In my modern algebra class we discussed completion of the rationals as a way to construct the real numbers.  But this leads me to wonder - How do we know that all of these approaches and constructions result in the same structure, namely $\mathbb{R}$? Also, are the real numbers  the only complete, totally ordered field? If so, why?


What sequence of documents should I read to know "all of" TeX and then LaTeX?

I know that there are a already number of questions on this site about good instructional (La)TeX materials for users at different levels.  What I am interested in, though, is what set of documents will give me (in which reading order) as complete an understanding as possible of TeX and LaTeX. If one would like to know all, why bother with "intros" anyway ;-)  I was gonna write that for TeX the best first document (and, in the sense described above, technically the only necessary one) should be "The TeXbook", but then there's e-TeX, which is not covered. And I don't know to what extent there is other, hidden advanced knowledge one can only learn only from various advanced tutorials or from looking at the source code.  Let's, for simplicity, assume that I am excluding knowledge about LaTeX packages from this question. For those, the best way is to read the package documentation. One should skim the package documentation of certain frequently used packages (those one is using) anyways.  Once one has an understanding of (e-)TeX, I have the same question for LaTeX 2e.  One reason for asking this question is that I never cease to be amazed at what gems of obscure tricks there exist. There's gotta be a way of acquiring this knowledge in a most efficient way other than by "reading around randomly and perusing the source code".


Most of time when I use Firefox my system freezes and needs to be restarted. Sometimes I use other apps and need to restart the system after the system. The system is updated. Firefox usually freezes when I'm on YouTube.  How can fix this?  My Ubuntu version is 18. It happen in this new version. Before the update it was good.


How can I enable AHCI mode after Windows Vista install in IDE mode and before/for Windows 7 clean install?

I just purchased a 2 TB Fantom USB 2.0/ external hard drive.  Unfortunately it revealed my oversight when my first custom system was built last summer. I installed Vista Home Premium 64-bit in  mode (default in BIOS) instead of the  mode, which would not only provide Native Command Queuing, but also hot plug of external hard drives I need now.  As expected, when I changed the Intel controller to ACHI in the BIOS, the system wouldn't boot any more as expected.  My motherboard is a Gigabyte GA-EX58-UD4P. Both my internal 750 GB WD Black caviar 7200 rpm hard disk drive and my eSATA bridge (providing two eSATA external connections) are connected on three of the six Intel SATA connectors controlled by the ICH10R () controller.  The internal hard drive is on SATA0 and eSATA connectors on SATA4 and SATA5. The two SATA connectors controlled by a Gigabyte controller (i.e. GSATA0 and GSATA1) are not used.  The external hard drive driver just installed out of the sudden on my last try as I was writing this post and after I tried to install SATA/RAID drivers while under Windows from Gigabyte website  for both Gigabyte and Intel controllers.  Note that Intel setup from MSM/iata_cd.exe gave me an error that my system did not meet the minimum requirement and closed. The new external SATA hard drive is now reported along with the internal hard drive in  under the IDE/ATA/ATAPI Controllers, with Intel(R) ICH10 Family controller Serial SATA controller.  I am about to upgrade to Windows 7 Home Premium 64-Bit, for which I'd like all SATA drives to operate in AHCI mode. It would allow my external hard drive with an eSATA connection to support hot-plugging and seems beneficial for the internal hard drive too, while multi-tasking.  Enabling the AHCI mode after a Windows Vista install with IDE mode enabled does not seem trivial in the few solutions I read - and a little confusing.  Questions:   Should I enable AHCI mode before (i.e. under Windows Vista) or during the upgrade to Windows 7? If you recommend it is done before, can I enable the ACHI mode without     re-installing VISTA? How?   Also, I have multiple partitions for the current Windows Vista install, with Users and Program Data on a different partition that the operating system. The current partition scheme will re-organized and simplified.   If you suggest to do it during the Windows 7 Custom clean install, will I still be able to modify this drive partitions scheme (using the Disk Option Advanced mode) in the same custom install session? Since the external drive is operating in IDE Mode with the ICH10R controller, what is the implication that it has no hotplugging capability? Where can it be stopped in the status bar? Is it safe to power it off when the system is running?


What is this electronics symbol (four triangles?)

The below image is from a service manual for a mobile radio. Note the small symbols that appear to be four triangles, point to point. I've searched far and wide and cannot identify that symbol. I have a nagging feeling that I've seen something like it in hydraulics, but never in an electronics diagram. I know that my radio doesn't have a bunch of stars of David printed inside it, so what could this symbol be?  Some of them have a line through the middle, others don't. Compare for example the ones near the labels "mic int" and "mic ext". Does this represent something, or is it a typo?


server file owner and group changed when editing file locally

If i edit the file from a remote server via text editor (geany, sublime text..etc) locally, the file user and group will changed to the logged user.   Let say if I accessing the remote file with root user (using caja file manager)  Before root user edit: file member:admin  After root user edit: file root:root  How do I prevent this?  UPDATE If I edit the files remotely with VIM, the owner and group remain the same. So, I think maybe it is related to the text editor??


What's the difference between unit tests and integration tests?    Are there different names for these tests? Like some people calling unit tests functional tests, etc?


The Proof of Wilson's Theorem using the auxiliary multiplicative modulous group

(self answered question, thanks for the hints Derek Holt provided:-))  problem 18,section 4 chapter 2 in Herstein's abstract algebra: Using the results of Problem 15 and 16,prove that if p is an positive odd prime number, then $(p-1)!\equiv -1 \pmod p$. (self answered question, thanks for the hints Derek Holt provided:-))  Problem 15: If $x^2\equiv 1 \pmod p$, then $x\equiv 1\pmod p$ and/or $x\equiv -1\pmod p$ Problem 16: If $G=${$a_k|1\leq k\leq n$} is a finite abelian group, then $(\prod^n_1 a_k)^2=e.$


Over at   suggested that I block commits instead.  However I don't know how to check a file ends with a newline. How can you detect that the file ends with a newline?


using .NET Regex.Replace() to replace expression more than once

I couldn't seem to find a match for this question so my apologies in advance if it's a duplicate.  Given the template: <<FirstName>> << FirstName >>  I want to replace both strings between the '<<>>''s using a single regex that should match both.   The following code doesn't seem to work the way I'm expecting:  [Test] public void ShouldReplaceMultiple() {   var pattern = "<<.*FirstName.*>>";   var template = "<<FirstName>> <<FirstName>>";   var replaceWith = "FOO";    var regex = new Regex(pattern);     Assert.AreEqual("FOO FOO", regex.Replace(template, replaceWith)); }   The output of the test is as follows:  Expected string length 7 but was 3. Strings differ at index 3.   Expected: "FOO FOO"   But was:  "FOO"   --------------^   I don't understand why both strings won't be replaced?


According to :     The electron has no known substructure. Hence, it is defined or assumed to be a point particle with a point charge and no spatial extent.   Does point particle mean the particle should not have a shape, surface area or volume?  But when I searched Google for the "electron shape" I got many results (like  and ) that says electrons are round in shape.


What are the Alternatives For RemasterSys?

I need an alternative software of Remastersys since it's not working in my system (Ubuntu 12.04.)  I want software just like remastersys. I don't want to install any new packages, I just want a piece of software that makes an ISO of my current system without any added packages.


How do you insert the current file name in Excel?

I am trying to view the file name that I am working on in the Excel spreadsheet of interest using a formula. For example if the file was called workbook1.xlsx then I would want cell A1 to show "workbook1.xlsx"   The formula that Microsoft's help site gives doesn't work:      =MID(CELL("filename"),SEARCH("[",CELL("filename"))+1, SEARCH("]",CELL("filename"))-SEARCH("[",CELL("filename"))-1)


2017: Is there a difference between a readonly field and a getter-only auto-properties?

Yes, I've googled the question but the answers I've found only refer to the old days, before there were getter-only auto-properties.  Today in C# you can declare this:  class Test {   readonly int MyField;   int MyProperty { get; }    public Test()   {     MyField = 42;     MyProperty = 47;   } }   Both declarations can only be initialized either at the line of declaration or in the constructor as seen above.  Is there still a relevant difference between those? Is one to be preferred over the other (e.g. in certain situations, except for interface declaration)?


Calculation of $\lim_{n\rightarrow \infty}\frac{n!\cdot e^{n}}{n^n\sqrt{n}}$

Calculation of limit $\displaystyle \lim_{n\rightarrow \infty}\frac{n!\cdot e^{n}}{n^n\sqrt{n}}$   Plan Stirling approximation $$n!\approx \bigg(\frac{n}{e}\bigg)^n\sqrt{2\pi n}$$ for large $n$  $$\lim_{n\rightarrow \infty}\frac{n^n}{e^n}\cdot \sqrt{2\pi n}\cdot \frac{1}{\sqrt{n}}=\sqrt{2\pi}$$  How would I evaluate the limit without Stirling's approximation?


Questions migrated to localized meta sites get the [discussion] tag in English even if it's synonymized to the localized tag equivalent

Questions that get migrated to localized meta sites have the  tag in English, instead of the localized equivalent of the tag. E.g. in Russian Stack Overflow: in question  base tag should be , not , which is a synonym in this case. For context, the system adds the  tag to questions that get migrated to meta sites, in order to ensure that all questions there have a required tag.


df on 7.7GB shows 400MB available while du -sh / reports 3.8GB used

I believe df is reporting incorrect disk usage, as I have the following problem:  I deleted a few files to free up space, then run the following:     $ df -H   reports 7.7GB on Volume and 400MB available, however, running:     $ du -sh /   reports 3.8GB usage, on this volume. There is a loss of roughly 3.9GB.  I have ensured there are no opens files using $ lsof and also rebooted the server after deletion.  FYI - OS Version: Centos 6.5  I would appreciate it if you would be able to guide me or point me in the right direction. Thank you.


Is there ever a right time to upgrade to full frame camera body?

Context  I've been shooting with an a6000 (APS_C mirrorless) and I plan to move on up to full frame, preferably mirrorless as well. I'm debating on when to upgrade, and probably don't plan to buy until next year.  I know I'll need to buy new full frame lens.  Question  Is there a "right" time to buy camera bodies, both mirrorless in my case as well as DSLRs? (I've seen the a7rII and like it but there might also be an a9 looming.) I feel that this is like smartphones in which the best time to buy is now as you might always be waiting until the next upgrade.   Related, are full frame bodies discounted during the holiday season or is that limited only to entry level bodies and older full frame bodies?  Related


Can you see if a game has trading card support on its 'Library Page'?

Right now on the Featured Items page of the store if a game has Card support it has a sash over the top left corner that says 'Cards'. On your profile, the badges section is a list of all your games that have badge/card support.    But at the moment I don't see anything on the game Library page in any of the 3 views (Detail, List, or Grid) that has any indication of card/badge support.   Is there an individual marker in any Library view (similar to the Cloud in List view that shows Steam Cloud support) to see if a game has trading card support?


the use of 'were' and 'was' when describing a situation

What is the correct use of 'were' and 'was' in an imaginary sentence such as: ''If I were to go biking I would be tired.'' How is this different from the sentences below: If I go biking I will be tired, or If I bike, I get tired. Does a sentence such as ''If I was to go biking, I would be tired'' make more sense?


How to reconcile the cashless human/Federation society with human traders and merchants

From a variety of sources, including , we know that the Federation (or at least the humans) don't use money. This raises the problem that humans frequently visit worlds where there is currency, and, in the case of DS9, operate a station that has currency frequently in use (for example, Federation personnel frequently attend Quark's bar). Additionally, we see human traders.   My question is, how do humans get "money" (credits, latinum, etc.)? How would a human even get the resources to purchase their own merchant ship or the resources to fill its cargo holds with merchandise? If Federation personnel can simply be given money for the asking, why haven't they poured so much money down Quark's throat that he chokes on it?


Finding Matrix A from Eigenvalues and Eigenvectors (Diagonalization)

Question:     Let $A$ be a $3 \times 3$ Matrix such that $[-3,4,1]$   is the eigenvector corresponding to eigenvalue $3$, and $[6,-3,2]$ is an eigenvector corresponding to the eigenvalue $2$. If $v$ = $[0,5,4]$, compute $A^{2}v$.      Hint: $[6,-3,2]+2[-3,4,1]$ = $v$   Where I'm stuck:  I know that we can  solve A with the equation:   A = $P^{-1}DP$, where $P$ is the matrix consisting of the eigenvectors and $D$ is the matrix consisting of the eigenvalues.  However, since $A$ is a $3$ x $3$, we should have a $3 \times 3$ matrix $D$ and $ 3 \times 3 $ matrix $P$ as well, consisting of the eigenvalues and eigenvectors respectively - and in this case, we only have two eigenvalues and two eigenvectors. Where can I obtain the other one of each?  Any help will be very appreciated.  Thank you.


Unable to install Midori browser on Ubuntu 18.04 LTS

I am trying to install Midori to Ubuntu, starting with:  $ sudo add-apt-repository ppa:midori   The response is:   Midori Browser     http://twotoasts.de/index.php/midori/  This PPA is signed. To add the GPG key to your apt keyring:    sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com A69241F1 Starting with Karmic, adding the PPA and its key is as simple as:    sudo add-apt-repository ppa:midori  You may also want to use the WebKit-team PPA:      https://launchpad.net/~webkit-team/+archive/ppa You can find unstable Midori versions at     https://launchpad.net/~midori/+archive/midori-dev  More info: https://launchpad.net/~midori/+archive/ubuntu/ppa Press [ENTER] to continue or Ctrl-c to cancel adding it.  Hit:1 http://security.ubuntu.com/ubuntu bionic-security InRelease Ign:2 http://ppa.launchpad.net/midori/ppa/ubuntu xenial InRelease                                                                Hit:3 http://ch.archive.ubuntu.com/ubuntu bionic InRelease                                                                       Ign:4 http://ppa.launchpad.net/midori/ppa/ubuntu bionic InRelease                                                          Hit:5 http://ch.archive.ubuntu.com/ubuntu bionic-updates InRelease                              Hit:6 http://ch.archive.ubuntu.com/ubuntu bionic-backports InRelease                                                      Err:7 http://ppa.launchpad.net/midori/ppa/ubuntu xenial Release                                                             404  Not Found [IP: 91.189.95.83 80] Err:8 http://ppa.launchpad.net/midori/ppa/ubuntu bionic Release                                        404  Not Found [IP: 91.189.95.83 80] Hit:9 http://archive.canonical.com/ubuntu bionic InRelease                Reading package lists... Done E: The repository 'http://ppa.launchpad.net/midori/ppa/ubuntu xenial Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/midori/ppa/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   Is there an easy way how to deal with that?


Ubuntu Keyboard shortcut to launch terminal is very slow

I frequently launch a terminal via keyboard command.  Normally it is very fast.  All my other launcher shortcuts still work quickly.  The terminal launcher is taking over 20 seconds before I see the terminal.  This just started a few days ago. I've tried the following with no change:   Changing the default terminal from gnome-terminal.wrapper to terminator. Creating a new custom shortcut. Changing the key sequence of the launcher.   All these resulted in the same 20+ second launch time.  Any ideas how to debug this issue further?


Can I use a US visa in a official but cancelled passport?

I would like to know the following:   Assumption: suppose a person has surrendered/cancelled his Indian official passport and gotten back his regular passport, but he has a US visa valid until 2020 in his official passport.  Can he travel to the US with the new official passport and enter with the visa in the surrendered/cancelled passport?


Show that $P_n(X)=\frac{(X+i)^{2n+1} - (X - i)^{2n+1}}{2i}$ is of degree $2n$, even..., using the binomial coefficients formula

In the previous questions i've proved that $(1+i)^{2n+1}=a_n+ib_n$ where $a_n$ and $b_n$ are $\pm 2^n$ and that $(1-i)^{2n+1}=a_n - ib_n$ and that $|P_n(1)|=2^n$ using the previous statements. But now I need to show that the polynomial $P_n(X)=\frac{(X+i)^{2n+1} - (X - i)^{2n+1}}{2i}$ is of degree $2n$, even (the coefficient in front of $X^n$ is non-zero only when $n$ is even, with real coefficients, and with $2n+1$ as a dominant coefficient, using the binomial coefficient formula. I also need to show that the coefficient $X^{2n-2}$ in $P_n$  is $\frac{n(1-2n)(1+2n)}{3}$. I don't really know how to use the binomial coefficient formula to prove those claims, any help would be greatly appreciated!


I'm really struggling on this question.  I've been thinking about it for awhile now but this is one of those where I don't really have much intuition on what to do.  Problem 3. Prove that if the limit $\lim_{x\to +\infty}f(x) =: L$ exists (finite or infinity) and the improper integral. $$\int_a^{+\infty}f(x) dx$$ is convergent, then $L = 0$.  Here is some facts that I know that I think I should perhaps use. Facts/Knowledge I know: The above integral can be rewritten as:  $$\int_a^{\infty}f(x)dx = \lim_{A\to \infty}\int_a^{A}f(x)dx$$  We know that limit as x goest to infinity of $f(x)=L$.  I need to somehow show that limit L is equal to 0. If I take the integral I get $\lim_{A \to \infty} F(A)-f(a)$ and I know this does not equal infinity as the integral converges.  I'm not sure if this is on the right track or what to do next. I was thinking maybe perhaps instead I could use the Cauchy Criterion to come up with a proof.  Note: I'm not used to doing proofs with Improper integrals.  Theorem 1 (Cauchy Criterion). The improper integral (1) converges if and only if for every $\epsilon > 0$ there is an $M\geqslant a$ so that for all $A, B \geqslant M$ we have $$\Bigg|\int_A^B f(x) dx\Bigg| < \epsilon$$


Story: Earth has no space travel, but aliens only have gunpowder weapons and blimps?

My wife read a book decades ago where the most feared and vicious alien race in the galaxy is a race that looks kind of like a teddybear. They arrive, and start to descend upon earth to conquer it...with their muskets, cannons and dirigibles. I think it's the US Air Force that intercepts them with fighter jets and, needless to say, blows them away. Other races show up to see what has these 'teddybears' so terrified...figuring if Earthling can terrify the t-bears, then maybe they can help defeat the "scourge of the universe" (which is the t-bears, as they have gunpowder and nobody else has anything even close to that). However, space travel is apparently 'simple' and the alien races are stunned that Earthlings haven't figured it out.  Anybody know what story I'm talking about? I'd like to read it.