Prove that if $\gcd( a, b ) = 1$ then $\gcd( ac, b ) = \gcd( c, b ) $

I know it might be too easy for you guys here. I'm practicing some problems in the textbook, but this one really drove me crazy. From $\gcd( a, b ) = 1$, I have $ax + by = 1$, where should I go from here? The extra $ac$ is so annoying. Any hint?    Thanks, Chan


Are incrementers / decrementers (var++, var--) etc thread safe?

Inspired by this question:   Take the following psuedo code:  class test {    int _counter;    void Increment()    {      _counter++;    }  }   Would this be considered thread safe on an x86 architechure? Further more are the Inc / Dec assembly instructions thread safe?


How can I use True Type Fonts directly with LaTeX?

everybody.  I'm writing a book and my publisher asked to me to write it with several True Type fonts.  I was researching about how to do it and I found that it is easier with XeLaTeX.  Then, I noticed that the fonts in the LaTeX tree have the .pfb extension.  After that I searched in internet and I found this ftp page    There are several True Type fonts in that ftp page with the .pfb extension.  My question is  Can I install (download and move to) these .pfb font files in my computer and use them directly in LaTeX, compiling with (for example) PdfLaTeX?  If it's possible, how can I do it?  Thanks for your help.


Summarizing entries by column using QGIS?

I have one field named (OBID) identificator of an municipal. Second field is ZAPOSL which indicates the number of employees in several stores in this municipal.  I wolud like to summarize all employees in each municipal.  Example: If the municipal ID is for example 55, QGIS should sum all ZAPOSL numbers which correspond to the OBID = 55.  See figure: OBID = 55: ZAPOSL: 2+0+18+4+8+0+4 = 36  ArcView knows that as Summarize and creates a new table with the result...


What does `--frontend` do in `do-release-upgrade` and where can I find the list of possible values?

While checking the , I found out that it has a --frontend argument that can be passed to the command along with a value. However, the manpage doesn't explain what the argument exactly does, or what are the available values for it.        -f FRONTEND, --frontend=FRONTEND               Run the specified frontend  My assumption is that it to allow us to go through a specific application like the Software Updater or the command-line. Can I find a better description and a list of possible values for that argument?


I want to use biblatex (with Biber) to produce my reference list, and I also want to use the bibentry package to print individual citations in the text. However, it seems that I can't do both.  In the example below, the \bibentry just produces empty output  \documentclass{article} \begin{filecontents}{ref.bib}   @Book{abramowitz+stegun,     author    = "Milton {Abramowitz} and Irene A. {Stegun}",     title     = "Handbook of Mathematical Functions with     Formulas, Graphs, and Mathematical Tables",     publisher = "Dover",     year      =  1964,     address   = "New York",     edition   = "ninth Dover printing, tenth GPO printing"   } \end{filecontents}  \usepackage{bibentry} \usepackage[backend=biber]{biblatex} \addbibresource{ref.bib}  \begin{document} Here's a citation \bibentry{abramowitz+stegun}  \nocite{*} \printbibliography \end{document}


Disable interactive logins in bash scripts

I have an SSH key based authentication setup for some deployment script. But there is a chance that the authentication files are not setup properly at some point. I don't want my shell scripts to ask for passwords, I want them to fail immediately.  Using      ssh  -o KbdInteractiveAuthentication=no -o PasswordAuthentication=no   -o PubkeyAuthentication=yes  test@host   or some thing along those lines does not work. I do not want to change configuration files since the script can be executed from any where.


Proving the kernel is a normal subgroup.

My professor proved that the kernel is a normal subgroup under a homomorphism f by saying. Let $h\in H$  by applying f to it  $f(ghg^{-1})=f(g)f(h)f(g)^{-1}=e $  My question is how is this a proof that the kernel is normal. What is the reason we apply f to it ? By applying f dont we just prove that $f(ghg^{-1})$ is normal ?


Prove $\sup \left| f'\left( x\right) \right| ^{2}\leqslant 4\sup \left| f\left( x\right) \right| \sup \left| f''\left( x\right) \right| $

Let $f\left( x\right)$ be a $C^{2}$ function on $\mathbb{R}$. Show that $$\sup \left| f'\left( x\right) \right| ^{2}\leqslant4\sup \left| f\left( x\right) \right| \sup \left| f''\left( x\right) \right| .$$


Are there good alternatives to "making the best of a bad situation?"

Life is full of adversity, and people facing challenging life circumstances have to find a way to cope. I'm interested in single words, phrases, or idioms that capture coping strategies. For example:     Jane's job was absurdly repetitive and oppressive, but for her family, she tried to make the best of a bad situation.   Are there good alternatives to the coping strategy of making the best of bad situation?   Clarification: I am looking for alternatives, especially idioms, that don't involve words like good and bad.


Comparison JNG-90 vs m98b vs M40A5 sniper bf3

How do these 3 sniping rifles compare in accuracy, damage, reloading speed, bulletdrop, rounds per magazine,...?


Geometrical Interpretation of a determinant

What is the geometrical Interpretation of a determinant? I know a bit about the geometrical Interpretation of a matrix      but don't have any idea about this


Touchpad scroll does not work in Whatsapp Web Application

I am using Whatsapp Web via its desktop application. It was running smoothly until I install the latest update for Windows. Now, I cannot two-finger scroll with my touchpad (ELAN) although it works with an external mouse. My touchpad scroll works well in all other platforms. What could be the reason for this? Thanks.


Closed formula for the sum of the following series

How can I find the closed formula for the sum $$1/3 + 1/27 + 1/243 + ...?$$


What are some uses of template template parameters?

I've seen some examples of C++ using template template parameters (that is templates which take templates as parameters) to do policy-based class design. What other uses does this technique have?


How do I get a US visa while on a student visa in Canada?

I am from India and have come to Canada on student visa. I intend to go to USA for my friend's wedding in the month of September. How do I start with my visa procedure?


I always thought that "sudo" just starts another login-process, specifically using "root" as a username and asking for the Password to login. After running some program, it ends and logs out (or: keeps the open session for some time and then quits it). No idea where I heard that from, but that seemed reasonable to me.   But now I discovered this sudoers-option:  ALL    ALL = (root) NOPASSWD: /my/command   This allows me to run any program from any user as a root without asking for any password. This left me wondering:  How does that work? How does a program gain user-rights? Does sudo need a server (running as root as daemon or so) and connects to that server, sends it what should be executed and that server executes it with root-rights?   How about other users?  Is there any good and simple explanation how this works?


How can I use etckeeper via sudo with different users and have the correct user in the commit message?

I'm working on a server with several admin users. Each of them can use sudo to make configuration changes. We're keepeing our /etc directory version-controlled using etckeeper.  However, when I or another admin calls sudo etckeeper commit COMMITMESSAGE, git uses the root user's name and e-mail for the commit message. Setting git config user.name on the etc repository doesn't work in this case, because then each time etckeeper commit is called, the same data will be used.  What I want is the actual user's name and email be present in the etckeeper git repository, so that from the commit log I can track down who did which change.  Any help is greatly appreciated!


best practices: include .cpp file in main instead of .h file when using templates?

I have a class Node with a template  this is header file  // node.h #ifndef NODE_H #define NODE_H #include <iostream>  using namespace std;  template <typename T> class Node { private:     T content;     Node<T> *next; public:     Node();     Node(T);      template <typename Y>     friend ostream &operator <<(ostream &, const Node<Y> &); }; #endif // NODE_H   and that's the implementation  // node.cpp #include "node.h"  using namespace std;  template<typename T> Node<T>::Node() {     content = 0;     next = NULL; }  template<typename T> Node<T>::Node(T c) {     content = c;     next = NULL; }  template<typename Y> ostream &operator<<(ostream &out, const Node<Y> &node) {     out << node.content;     return out; }   and here is the main file  // main.cpp #include <iostream> #include "node.cpp"  using namespace std;  int main() {     Node<int> n1(5);      cout << n1;      return 0; }   this way, it works perfectly, but i don't think it's good to include cpp file.  so i included node.h but i get this errors  pathtofile/main.cpp:8: error: undefined reference to `Node<int>::Node(int)' pathtofile/main.cpp:10: error: undefined reference to `std::ostream& operator<< <int>(std::ostream&, Node<int> const&)'   I really want to follow best practices, and i always separate code declaration from implementation; but this my first time working with templates.


How to capitalize a text that is written in uppercase?

I have a text that is written in uppercase. Example:  THIS IS UPPERCASE   What I want is to make it look like this (capitalize it):  This Is Uppercase   I just found out I cannot do it with CSS since text-transform: capitalize only works on the first letter, so the output is still:  THIS IS UPPERCASE   Is there any way with jquery to achieve this effect?  EDIT:  This is my HTML code:

NAME SURNAME

   NAME and SURNAME are dynamic variables, but some of the data is written in UPPERCASE, some is written in lowercase and some is written in Capitalize. I just want to uniform the names with Capitalize, possibly including the javascript in my html file, but I have trouble capitalizing strings written in uppercase.


How long are Hot & Spicy Beer Battered Jalapeno Slices good in Freezer past Best by Date?

I have a package of Great Value Hot & Spicy Beer Battered Jalapeno Slices that state that they are best if used by February of 2020. It is January 2021. What is your opinion of whether or not they are still good? They have been in the freezer the entire time.


Unparsed HTML shows on search result page

When you search on any of the SE network sites, with a tag (so that a description is shown); it shows the tag info content box, with the highlight-search-term span elements.  For eg. I searched ; ; and the results are as shown:                  Notice the <span class='search-highlight'> boxes around searched tag terms.


Mods should be able to suppress questions from the Multicollider

This came up over in EL&U chat, but since it affects the whole network I'm bringing it up here. Related topics from meta.english.stackexchange.com:      It sometimes happen that a question comes up which is clearly on-topic for the site in question, but which is likely to wind up on the multicollider and attract a lot of attention for bad reasons. At EL&U this happens when we get questions about swear words or words for private parts. These questions are explicitly on-topic for us, and they can be well-asked in a way that clearly isn't just meant to titillate. For this reason, it's not enough to say that these questions should be closed. Questions of this type can be asked and answered productively, but we still don't want tons of drive-by users from other sites voting on them and creating extra work for the mods with their crap answers. Unfortunately, the current multicollider implementation promotes such questions across the whole network, where they get upvotes and answers in disproportion to their quality, solely because of the giggle factor.  This is bad for a variety of reasons. It pollutes the quality of the cross-site promotions, fills the multicollider up with trivia, and it creates the impression that EL&U is all about swear words and slang, an impression we're trying to combat.  There should be a way for mods to block a question from multicollidering. The EL&U mods have a policy of pre-emptively protecting questions like these that are likely to attract unserious answers, and it's been suggested that protected questions should be filtered from appearing on the multicollider and cross-site advertisements. But really, any mechanism to keep "attractive nuisance" questions from getting excessive attention would do.


Plotting the Graph of $1/I$ on the Y axis against R What does this represent?

What does the gradient, the intercepts represent, what is the equation of my line, and how do I use this information to calculate emf?


Benefits of os.path.splitext over regular .split?

In , the votes clearly show that the os.path.splitext function is preferred over the simple .split('.')[-1] string manipulation. Does anyone have a moment to explain exactly why that is? Is it faster, or more accurate, or what? I'm willing to accept that there's something better about it, but I can't immediately see what it might be. Might importing a whole module to do this be overkill, at least in simple cases?  EDIT: The OS specificity is a big win that's not immediately obvious; but even I should've seen the "what if there isn't a dot" case! And thanks to everybody for the general comments on library usage.


$\ f \colon X \to X $ ,continuous function where X is compact,Hausdorff space.Show $\exists A$ st $f(A) =A$.

Suppose $\ f  \colon X \to X $ is a continuous function from a compact,Hausdorff space to itself. Prove that there exists a subspace $A$ such that $f(A) =A$.  I came up with an answer based on nets (see the answer below). But i am not very much familiar with nets. So please point out,if there is any error in argument.  Let $Y=f(X)$ then $X= \mathop{\cup}_{y  \in Y} f^{-1}(y)$ where the union is over disjoint sets. Since each of the pullback is a closed set. Being in a normal space, $\forall \ f^{-1}(y), \  \exists \  U_{y}$ open in $X$ such that  $f^{-1}(y) \subset U_{y} \subset \overline{U_{y}} \subset X$ .  Hence $X = \bigcup_{y \in Y} U_{y} $.  This open cover has a finite subcover. $X=U_{1} \cup U_{2} \cup \ldots \cup U_{n} $. Let $\Sigma = \lbrace A \  \ \vert A \subset X \rbrace$, suppose $\nexists$ any $A \in \Sigma$ st $f(A) =A$ then $\forall A \in \Sigma , \ \exists \ f (x)_{A} $ st $f (x)_{A} \notin A$.  define partial order on $\Sigma$ by set inclusion so that it becomes a directed set.   Let $\ell \colon \Sigma \to X$ be a net such that $\ell(A) = f(x)_{A} $. For simplicity let us represent it the net by $(f(x)_{A})$.  Since $X$ is compact,every net has a cluster point,call the cluster point of the above net as $p$.  Since $p \in X=U_{1} \cup \ldots \cup U_{n} $, we may assume $p \in U_{1} $.  Let $U_{1}$ be the neighbourhood of $p$ and $A=   U_{1}$ then $\exists  \ B \in \Sigma $  such that $ A \subset B $ and $f(x)_{B} \in U_{1}$. But $f(x)_{B} \notin B \Rightarrow f(x)_{B} \notin A=U_{1}$.   This is a contradiction. $\square$


Is there a way to find the font used in this image?

Which font is used in this image or how can I find?


A general explanation of rim, tire and tube specifications

My bike's manufacturer page specifies that it has a rim size of 700CX14GX36H.  It provides a tire size of 7X28C.  It also mentions that it uses high performance 700C tires, which I think is also referenced in the rim size.  I just replaced my tube by myself for the first time, and it was easy enough to determine that I needed a 700x28c size tube, but I would really like to know what all these specifications I'm seeing mean.    Can someone provide an explanation of what general rim, tire and tube size specifications mean?


can i use my visa Schengen for my first trip to a different country other than it issued from?

i have a Visa type C , Multiple Entry with 1 year of validity to the Netherlands(issuing Country), so i want to visit first Spain for a week and then go to my destination which is the Netherlands. can i do this without having any problem in my upcoming application ?


Depends on lib32gcc1 , libc6-i386 , can't install neither

I tried to install catalyst for my Radeon Graphics on 13.10  , but looks like everything went wrong . Now I can't install any software , and the software center says : The following packages have unmet dependencies:  fglrx: Depends: libqtcore4 (>= 4:4.5.3) but 4:4.8.4+dfsg-0ubuntu18 is installed        Depends: lib32gcc1 but it is not installed        Depends: libc6-i386 but it is not installed xserver-xorg-video-intel: Depends: xorg-video-abi-13 but it is not installed   I am a noob , thus I really don't know what to do . I tried to install lib32gcc1 and libc6-i386 via apt-get and it didn''t work also for unmet dependecies .  I downloaded .deb package of libc6-i386 but I couldn't install it. any help ?


How to extract file from tar.gz archive to different directory in bash

I have tar.gz archive on external drive and to extract I need to copy to my home directory and then extract. Is there a way to have it in one go, extract to /home/me directory without the need to copy it first?


what statistics test should i run to show that something is significantly different from 0?

I have the results of a lab test for bacterial growth on agar, in my sample, most colonies grew a small amount and a couple grew a lot and a couple did not grow at all. I have to use the different lengths of the growth ring radii to show that the sample of radii is significantly different form 0.  In other words, is there a statistical test that can show that this sample is significantly different from 0, so that I can say with 99% confidence that it is the same for the population?  if it helps, the growth colony ring radii from my experiment are   3, 2, 4, 2, 2, 2, 0, 0, 4, 0, 0, 1, 14, 11, 5, 6, 6, 3, 4   radii of 14 and 11 seem to be outliers to me as well but I'm not sure.


The average determinant of all integer matrices with coefficients $0,1,2$

Let $S$ denote the set of $A \in M(n,\mathbb R)$ such that every entry of $A$ is either of $0$, $1$ or $2$, then is it true that $$\sum_{A \in S} \det A \ge 3^{n^2}\ ?$$


What is the difference between .profile and .bash_profile and why don't I have a .profile file on my system?

So I'm pretty new to Linux and recently installed Fedora 19 on my netbook. I want to have a deeper understanding of Linux and the CLI so I'm now reading .  In exercise 3 the author gives the following commands:   ls -al cat .profile   I try to follow these instructions but to no avail. There is no .profile file in my user name directory as I can see from ls -al. From what I've learned the .bash_profile and .profile file are practically the same. The only difference I concluded from my research is that .bash_profile gets checked first.   What I don't understand is why are there multiple files for the same function in Linux, why is the Author using .profile and not .bash_profile (if I understand correctly .profile won't be read when the system finds .bash_profile first) and how comes that I don't have the .profile file on my system?


Help defining objective function and constraints to minimize standard deviation of list of points

Situation: I am trying to minimize the standard deviation between a series of points of differing heights in a list with the constraint that each point in the list can be raised anywhere from 0 to 2 units in order to minimize the standard deviation between points. Example: I have a list of points which are equidistant on the x axis but not the y axis. h = [20, 24, 28, 24 ,20 ,18, 20, 32 ,30, 28, 20 ,24] Where each number in the list represents that point's height. I also have the constraint that each point in the list can be raised by a c value anywhere from 0 to 2 in order to help achieve a smaller standard deviation. I am trying to create an algorithm that does the optimization of minimizing the standard deviation of the points of h with the constraint that each point in h can be raised by 0 <= c <= n for an h of any length with any values and with any n > 0 I am very new to optimization problems and although I have seen problems that look similar to my question, I have not seen any that I've been able to gather enough information to help push me further towards an answer. If possible, I was hoping someone would help me define the objective function, constraints, and other necessary functions that would lead me to an answer. This is not a homework problem so therefore I have no course material to help guide me to an answer. The only guidance I have is from the comments and answers to this post. Please understand that I am in no way a mathematician so I really need all the help I can get. Thanks!


Is it necessary to take Malaria medication in Laos?

I'm headed to Laos and Cambodia and I'm worried about the side effects of the Malarone anti-malaria medication. Is it necessary to take this? What is the likelihood of transmission of malaria in this country? I know this is not a high risk.


Would many extremely fine (solid) granules exhibit similar properties as a fluid?

A while ago this random thought crossed my mind: I am not even sure if the question is valid or makes sense, but I can sort of imagine a powder (consisting of of granules with a diameter way less than a nanometer across) behaving like a fluid (at least they would have a similar "macroscopic" behaviour). Of course I do not expect this powder to have similar chemical properties, but maybe that's the case. Is there any information on "simulating fluids with many tiny solid objects"?


I am not getting the minor radius for even after scrolling down.

when i am selecting torus this(image attached) is what i am getting and there is no option of changing minor radius.


I tried like: here slant height $l={h\over\sin 60}$ and radius of the base of the cone $R=h\tan 60$ but I am not able to find the radius of the sphere.


Can command substitution be nested in variable substitution?

I would like to use variable substitution on a particular string that I access via a command. For example, if I copy something into my clipboard, I can access it like this.  $ xclip -o -selection clipboard Here's a string I just copied.   If I assign it to a variable, then I can do variable substitution on it.  $ var=$(xclip -o -selection clipboard) $ echo $var Here's a string I just copied. $ echo ${var/copi/knott} Here's a string I just knotted.   However, is there a way to do variable substitution without assigning it to a variable? Conceptually, something like this.  $ echo ${$(xclip -o -selection clipboard)/copi/knott} bash: ${$(xclip -o -selection clipboard)/copi/knott}: bad substitution   This syntax fails, because var should be a variable name, not a string.


Why can't I find the Karin Kuruma car in the southernsanandreasuperautos.com website? Do I have to do a specific heist/setup/mission or be at a certain level? I'm level 25 in GTA Online.


Ristretto Image Viewer in XUbuntu does not open .CR2 images. Bug? or not supported?

Context: Image Viewer (the default viewer in Xubuntu) does not show images with extension .cr2 (the raw image of Canon version 2). If I try, the program opens but no images are displayed. And NO errors are prompt. Questions:  Is there a way to enable the feature? Maybe some extension of the Image Viewer? If not, are there other alternatives?


How to get Beamer Math to look like Article Math

In a LaTeX article, the math characters are more "curvy" than the text characters:  \documentclass[12pt]{article} \begin{document}  $x^2 + y^2 = z^2$ \end{document}     In a beamer presentation, the math characters do not have the same curves:  \documentclass{beamer} \begin{document} \begin{frame}  $x^2 + y^2 = z^2$ \end{frame} \end{document}     Question  How can I get the beamer math to look just like the article math?  I would prefer if the solution was a single line (that I could place at the top of my LaTeX file) as opposed to something that needs to appear next to every piece of math.


How to get current time elapsed percentage of today?

Im trying to get the current time elapsed percentage of todays time. It can be either javascript or php. How can I do that ?


How to list all packages installed as dependencies in Terminal, and what installed them?

Is there a way in Terminal to list all programs which have not been installed by me, but other programs as necessary dependencies? And can I at the same time view which programs they were installed by?


Answer count in /questions differs from count on question page

I occasionally notice that a posts answer count is different on /questions as it is inside the actual post, and until now I just ignored it assuming that it was either something in cache, a deleted/ added post since I last looked, etc.  But I finally found an example of one that I believe the count to truly be wrong on:    Here's a screenshot of /questions   And here's on from inside the post. Mind you depending on your rep, you may only see that there are 2 answers inside the post because 2 others were deleted by owner.     Anyway, on to my proof! I first noticed this post when it contained four answers and none of them had been deleted. As it seemed that the current answers solved the problem I exited the post, only to see /questions refresh and show that the post now contained 3 answers.  Intrigued I reentered the post curious to see who deleted their post, and found as expected that the answer count was still 4. Left the post again and the same thing happened!  I'm not arguing that the posts internal answer count shouldn't reflect deleted posts because I like the feature. But, is there a reason that a posts answer count in /questions doesn't reflect deleted posts as well?


I've submitted a sitemap (XML) of my Drupal (7) site to Google Webmaster Tools and it says that my sitemap contains 285 pages and that only 87 pages were indexed.  There are no errors and no additional info or problems. There are no duplicates.  Any idea why most of my pages weren't indexed?   When I Google my site ( i.e.: search the following in Google : site:www.mysite.com/),  I get ~200 pages (results) which is better, but not perfect.


Can a vector space with infinite basis be represented as a countable union of proper subspaces?

I am familiar with the case where the basis is not infinite (it becomes the case that it CANNOT be represented as such). However, many sources suggest that this is not the case for an infinite basis. How could one go about proving this?


Could there be 3 particles (instead of only 2 particles) that could be connected by same quantum entanglement (like minus, plus and "some third position")?


I am building on  answer. Essentially I have an initialisation vector $iv$, a ciphetext $c$ and a plaintext $p$. The plaintext was encrypted using AES CBC. The aim is to modify the first 4 characters of the plaintext so that it becomes $p_{target}$.   Ex:   $p$ = 'SEND_DOGGOS_LOVE'  $c$ = 0x63fd039cc488dd7d937677b322a7763c  $iv$ = 0xa9e459b1a2e68cd7db06cf24b7e0bde8  $p_{target}$ = 'CATS_DOGGOS_LOVE'  My understanding was that to achieve that, I can change the $iv$ by simply xoring the first 4 chars of $iv$ with the result of $xor($'CATS','SEND'$)$. This however doesn't seem to work as I get a nonsensical plaintext. What am I missing?


Check Proof of total orders are maximal orders

Recall: A set $X$ together with a binary relation $\leq$ such that for all $x,y,z\in X$,  O$1$. $x\leq x$  $O2$. $x\leq y$ and $y\leq x$ then $x=y$  $O3$. $x\leq y$ and $y\leq z$ then $x\leq z$  is called an ordered or sometimes a partially ordered.   An ordered $(X,\leq)$ is called a total order if for all $x,y\in X$, either $x\leq y$ or $y\leq x$.   Theorem 1. Show that total orders are max orders.  Let $\leq$ be a total order on $X$. There is no partial order on $X$ which extends $\leq$ because $\leq$ is total order.   Theorem 2. Show that maximal order is total order.  Let $\leq$ be an partial order on $X$ which is maximal. Since $\leq$ is maximal, any two elements of $X$ can be compatible via $\leq$, hence $\leq$ is total order.  May you check my proofs? Can you give me alternative proof? Thanks...


Stress tensor: forces on the other three faces of the infinitesimal cube

Cauchy stress tensor contains the components of forces per unit areas on the three faces of the infinitesimal cubic element in picture.  Probably it is trivial question, but, while I understood the meaning of the tensor I do not understand why only these three faces of the cube are considered. What does happen on the other three faces (the ones not visible in the picture)? Are maybe forces there equal in magnitude but opposite in direction?


Prove that $|a+b|^p \leq 2^p \{ |a|^p +|b|^p \}$

For any real numbers $a$ and $b$ and $1 \leq p < \infty$, prove that   $$|a+b|^p \leq 2^p \{ |a|^p +|b|^p \}$$  This inequality is given in the the book Real Analysis by Royden, Chapter $7$, page $136$. I don't understand how the author comes to this inequality. Can anyone provide some hints?


I saw two less than signs on this Wikipedia article and I was wonder what they meant mathematically.    EDIT: It looks like this can use TeX commands. So I think this is the symbol: $\ll$


Attempt to invoke virtual method on a null object reference issue

I am developing an App which uses the following code. It is generating an unexpected error as "Attempt to invoke virtual method on a null object reference". I do not understand the reason why this is happening. The error is thrown as the line containing t[i].setTestname(getData(exams[i]));. Could someone please point out what I am doing wrong. Could use some help over here.  void processTestPerformance() {     String exams[],rawdata;     rawdata=data.toString();     int numberoftests=getNumbers("tabletitle03",rawdata);     Tests[] t= new Tests[numberoftests];     exams=new String[numberoftests];     rawdata=rawdata+"tabletitle03";     for(int i=0;i<numberoftests;i++)     {         int j=rawdata.indexOf("tabletitle03");         int k=(rawdata.substring(j+1)).indexOf("tabletitle03");         exams[i]=rawdata.substring(j,j+1+k);         t[i].setTestname(getData(exams[i]));         rawdata=rawdata.substring(k);     } }   The code for class Tests is as follows:  public class Tests {     public int numberofsubjects;     public String testname;     public Subject s[];     public void setS(Subject[] s)     {         this.s = s;     }     public void setNumberofsubjects(int numberofsubjects)     {         this.numberofsubjects = numberofsubjects;         s=new Subject[numberofsubjects];     }     public void setTestname(String testname)     {         this.testname = testname;     } }   Thanks in Advance.


Didn't find any talk of this so my curiosity got the best of me.  How do migrations handle favorited questions? My guess would be the favorite link would stay on the original site to the closed migrated question and I would assume any favorite marks would be reset on the site migrated to.  This isn't really that important, but just curious what happens.


How to add additional clock in Ubuntu 18.04?

It was quite simple in Ubuntu 16.04 to add additional clock from different time zone. But I am not sure how to add in 18.04, I checked the settings but it doesn't have any options. Any suggestions?


Are there disadvantages to a prosumer camera for a beginner, aside from cost?

I basically decided on a whim (from reading this site, talking to some friends, and always admiring great photos) that I want to get into photography.  Are there disadvantages to starting out with a prosumer camera like the Nikon D7000? I know stuff will be more expensive, but will there also be greater frustration or complexity?  (I am the kind of person who tries to find reasons to justify the extra cost even when I know deep down that it's not necessary...)


Is there a textured but unlit (full bright) viewport mode?

I'm trying to display models that have shading drawn or baked directly on the textures, but I can't figure out how to disable Blender's default scene lighting. If there are no lights in the scene, everything is black, but I want to see the textured objects fully bright. How do I disable the lighting?  NOTE: Just before posting this, I found the "Shadeless" material property, which does more or less what I want. However, is there a way to globally toggle the default lighting?


Transit Visa for Canadian Passport Holder

I am a Canadian travelling to Canada from India Via. Brussels. There is a layover time of ~ 3 hours and 45 minutes in Brussels on the same day. My travel is from Mumbai (India) - Brussels - Toronto (Canada)  Do I need to get a Transit Visa?  Please advise.


If $L/K$ normal and $H = \operatorname{Aut}(L/K)$, then $L/L^H$ is separable and $L^H/K$ is purely inseparable.

I need to prove the following:     Let $L/K$ be a normal field extension. Denote by $H=\operatorname{Aut}(L/K)$ the Galois group of the extension, and by $L^H$ the fixed field of $H$ in $L$. Prove that $L/L^H$ is separable, and that $L^H/K$ is purely inseparable.   For now, we tried to use the fact that an extension $M/F$ is separable (purely inseparable) if the number of homomorphisms $\phi:M\to \overline{M}$ that preserve $k$ is $[M:F]$ ($1$). We did not manage to conclude any results, and moreover this works only for finite extensions. How should we proceed?


Science fiction novel with the title "T" (which is also the name of the protagonist)

I'm pretty sure the title was "T".  It's about an alien race at war with humans. They decide to end the human race by destroying Earth before humans evolve. They send some humans through space and back in time to do the job.  I think the humans have single letter names (A, B, C, etc) They have raised/cloned the humans just for the job and to save space in their ships they have only a head, a body and one arm. Most don't make it.   The aliens don't know that there were 2 more planets in the past and they count the planets in from Pluto. One human hits a planet and completely destroys it and T hits a glancing blow and just breaks up his target forming the asteroid belt.


distribution of primes with reference to last digit

Any prime greater than 5 shall have 1,3,7 or 9 as last digit. Are the primes  equally distributed among the above four last digits or any  bias for  any particular last digit say  up to 10 to the power  12 or higher. I have recently read an article in Scientific American that adjacent primes are unlikely to share the same last digit. Is it possible to predict the distribution among the last digits as we go higher?


How do I address unchecked cast warnings?

Eclipse is giving me a warning of the following form:     Type safety: Unchecked cast from Object to HashMap   This is from a call to an API that I have no control over which returns Object:  HashMap<String, String> getItems(javax.servlet.http.HttpSession session) {   HashMap<String, String> theHash = (HashMap<String, String>)session.getAttribute("attributeKey");   return theHash; }   I'd like to avoid Eclipse warnings, if possible, since theoretically they indicate at least a potential code problem.  I haven't found a good way to eliminate this one yet, though.  I can extract the single line involved out to a method by itself and add @SuppressWarnings("unchecked") to that method, thus limiting the impact of having a block of code where I ignore warnings.  Any better options?  I don't want to turn these warnings off in Eclipse.  Before I came to the code, it was simpler, but still provoked warnings:  HashMap getItems(javax.servlet.http.HttpSession session) {   HashMap theHash = (HashMap)session.getAttribute("attributeKey");   return theHash; }   Problem was elsewhere when you tried to use the hash you'd get warnings:  HashMap items = getItems(session); items.put("this", "that");  Type safety: The method put(Object, Object) belongs to the raw type HashMap.  References to generic type HashMap<K,V> should be parameterized.


Safe conversion from integral value to pointer

How to safely convert unsigned integral value (e.g. uint32_t, uint64_t) to a pointer of particular type? For instance I have: using my_uint32_t = unsigned int; using my_uint64_t = unsigned long long;  struct Sample {     my_uint32_t address;     my_uint64_t address_64; };  Sample sample; /* Just for reference here */  struct TargetStruct {    /* Some member variables goes here */    ... };  The goal is to access the object of TargetStruct type existing at Sample.address or Sample.address64 respectively. I tried to use: TargetStruct * target = reinterpret_cast<TargetStruct *>( sample );  It works but is that safe? I know the rules say reinterpret_cast shall be avoided as unsafe but is there any other way to make it safely? I cannot go over my "inputs" - the Sample struct and it's content - it is simply given but I have to use the data stored in there in such usafe way... I am using C++20 so I am about to avoid C-style casts...


How can I go away from root user in ubuntu?

I tried to type in 'exit' and tried cntrl+d too but they both just close the terminal. Why is this? Is there another way to move away from root user?


I have a field called T_Amount data type is float,  e.g= T_Amount=11800  When i make formula in query (11800/24)*35.25=17331.25  but actually if i make in calculator (11800/24)*35.25=17331.24999  i want this full figure.


Pronunciation of 'deserved' in different contexts?

First, may I begin by saying that I love the English language! After so many years, I still find myself learning something new each day.  The question  has been identified as a possible duplicate of this question, but therein an enumeration of such words is called for, whereas here I am asking about the pronunciation of a certain adjective within this group.   could also be argued as a duplicate of my question, but what I want to know is far less broad, revolving around the pronunciation of deserved.  That settled, my question today revolves around the pronunciation of deserved in differing contexts. In British English at least (I can't speak for American English, unfortunately) there are no less than several heteronyms which end in ed.  Among these are:   Blessed (past-tense verb)/blessèd (adjective) Beloved (adjective)/belovèd (adjective) Learned (past-tense verb)/learnèd (adjective) Dogged (past-tense verb)/doggèd (adjective) Legged (past-tense verb)/leggèd (adjective, usually hyphenated to another word)   Of course the grave accents aren't strictly necessary (context is usually telling) but I want my point to be clear.  I got the impression that deserved belonged to this class of words, i.e. deserved (past-tense verb) and deservèd (adjective). If this is archaic, then perhaps what confused me is that the adverb deservèdly and the noun deservèdness are pronounced in four syllables.   I can't decide whether the adjective is pronounced in two or three syllables. The pronunciation of well-deserved may be telling here.  I have checked this in a few dictionaries, but come to no conclusion. The Cambridge Dictionary, usually trustworthy in such (fine) matters, gives the pronunciation of any form of deserved as .


My Question is i have document which contains some text and equations. The problem is how can i break a long equation whithout disturbing the equality sign in the next age.   MWE  \documentclass{article} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{mathtools} \usepackage{amssymb} \usepackage{lipsum,lineno}    \begin{document} Some text Some text Some text Some text Some text Some text Some text. Some text Some text Some text Some text Some text Some text Some text. Some text Some text Some text Some text Some text Some text Some text. Some text Some text Some text Some text Some text Some text Some text. Some text Some text Some text Some text Some text Some text Some text. \begin{align*} a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b\\ a&=b \end{align*} \end{document}


Redirect stderr to terminal and also file in bash

I have a peculiar case here which can be summed up as follows:  I want the entire error/stdout messages to be redirected to a file from my script but also there is one particular line which i want to redirect to terminal and also redirect that to the file.  This is the code:  exec &>test.log echo "Check if this line is going to test.log" echo "This should go to stderr" >> /dev/stderr   Now the last line should go to both stderr and test.log.  Can this be achieved somehow in bash ?


After running update via terminal on Ubuntu 13.10 I am getting "Failed to fetch" error msgs. fixes?

Again, I am using Ubuntu 13.10  These are the index files that failed to download:   W: Failed to fetch http://ppa.launchpad.net/ubuntu-x-swat/x-updates/ubuntu/dists/saucy/main/binary-amd64/Packages  404  Not Found  W: Failed to fetch http://ppa.launchpad.net/ubuntu-x-swat/x-updates/ubuntu/dists/saucy/main/binary-i386/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead.   How can this be fixed?


Is there any way to copy file's content in clipboard without opening the file?

Always, I am using vim as my text editor. But, when I want to copy full file's content in clipboard to paste another place I open the file in gedit and press CtrlA and then CtrlC.  Opening the file in text editor and pressing CtrlA and then CtrlC is overhead to me. Because I have to open the file in text editor, although I don't edit the file.    So, if there is any command that can copy the file's content in clipboard it better. e.g. clip file.txt    There also a possibility to gain this feature in vim by mapping CtrlA to some command or make a clip command to copy. But, I don't know how to copy entire file in vim using command.    N.B. My vim doesn't support +clipboard.


How to prevent an update to install on Windows 10

There is a recent update to Windows (KB4013429) that is incompatible with an application that we are using. I would like to prevent this update from installing. How can I achieve this ? EDIT: The tool suggested in the answer gives shows only five 'hideable' updates out of tens (or even hundreds).


Is it correct to append "no" to a question?

I have always been puzzled by some sentences people make that end in a no. For example, let's say someone instructed you not to leave your post before they arrive. Then they return but you're not there. When you finally meet them, they say:      So you decided to wait for me elsewhere than we had agreed, no?.   What is the meaning of no and what should I answer?


When you want to say that someone doesn't know anything about a particular thing, do you say they don't know jack about it, or that they know jack about it?  I've seen it used both ways. Which is correct?


tranfser of electrons between two metals and a wire

If you have a circuit of a battery, a Resistance and a light connected with a wire by example: in the middle the wire is cutted in two pieces. if you connect each piece of wire with a metal object and put those twee metal objects together so the current can flow to the resistance and the light. How is it possible that the electrons can flow from the wire to one of the metal objects into the other metal object and again in the wire? I do understand how electrons move in metals and wires, but i don't know how the transaction of electrons between those components goes. Is it really that simple that electrons just can flow from one object into another of is the (kinetic) energy passed through when an electron clashes with the edge and that energie is passed through to the other object?


I want to run   I opened the developer tab in excel, no clue what to do now. I tried creating a "macro button", and then paste the function code in the macro script, but if I press play I get a error related to Private Sub CommandButton1_Click()   and if i try to save the macro, I get this dialog box:


Recovering the command used by a launcher icon

How do I trace back to the exact command run by the unity launcher for a given launcher icon? In 14.04 at least, hovering (or right-clicking) an icon on the launch bar provides no option to arrive at that information.


Converting 4-band TIF to PNG while keeping all 4 bands?

I have a number of aerial photos containing both RGB and a near-infrared band. The images are in TIF-format, however I need to convert them to PNG without losing any of the bands. I have tried converting/exporting data in ArcMap, however this fails, unless I choose to "use renderer" in the "Export Data" dialogue, resulting in only 3 bands being saved.  I have also tried the GDAL-translate alghorhitm in QGIS, however this didn't seem to work either.  Do I have any other options?


Where can I ask a question about why large-scale encoding choices were made?

I want to know something about why certain operating system makers chose CR vs LF vs CRLF in the present, particularly the usage of CRLF in Windows. Where would be the best place to ask this?


python 3 remove leading substring from string

Suppose I have a filename ./file and I want to remove the leading ./ (if it starts with ./). What would be the best python way to do this? My take at this is:  if filename.startswith("./"):   # remove leading ./   filename = filename[2:]   Isn't there a more elegant way?  PS: it should remove the leading part only if it matches exactly, think of the following filenames:  ./filename .configfile ../file ./.configfile


Object appears in Object mode but not in Render

Learning Blender 2.8. Frosting with sprinkles Object appears in object mode but not in render. Any help would be appreciated.  Another note is that when I toggle to edit mode on the mug or plate I can see the object in edit mode. But when I toggle to edit mode on frosting with sprinkles. I doesn't show up in edit mode.


Getting 404 when closing a deleted question

I flagged . I also wanted to close-vote. But the post was deleted in the meantime by Community♦.   Always when hitting the close button I got a 404 error message:


How do I turn on autofocus with a Nikon D5300 and a Nikkor 50mm 1:1.8 lens?

How do I turn on autofocus? Using the Nikkor 50mm 1:1.8 lens.   I've gone into the menu selection and have fooled around with the AF settings but camera is still not focusing automatically...  When I click the info button, the MF button is not highlighted and I'm not sure how to get to it to see if that will do the trick.  At a loss! Help!


I am flying to Montreal from Prague and have a 6-hour layover in Amsterdam from 8:40AM to 3:20PM. Is it possible to go outside the airport in 6 hours? What could I possible do and see in 6 hours (considering time for passport control and getting to the city and back to the airport)?


I can't update software packages. Error says 'Failed to load package list. This is a serious problem, report it to the developers'

**Failed to load the package list**  This is a serious problem. Try again later. If this problem appears again, please report an error to the developers.  Details E:Unable to parse package file /var/lib/apt/lists/ppa.launchpad.net_tsvetko.tsvetkov_trusty-backports_ubuntu_dists_xenial_main_binary-amd64_Packages (1),  E:Unable to parse package file /var/lib/apt/lists/ppa.launchpad.net_tsvetko.tsvetkov_trusty-backports_ubuntu_dists_xenial_main_binary-i386_Packages (1),  E:Unable to parse package file /var/lib/apt/lists/ppa.launchpad.net_tsvetko.tsvetkov_trusty-backports_ubuntu_dists_xenial_main_binary-all_Packages (1),  E:Unable to parse package file /var/lib/apt/lists/ppa.launchpad.net_tsvetko.tsvetkov_trusty-backports_ubuntu_dists_xenial_main_i18n_Translation-en (1),  W:You may want to run apt-get update to correct these problems,  E:The package cache file is corrupted


I know this has probably been asked before, but I couldn't find it with Google.   Given   Linux Kernel No configurations that change $HOME bash   Will ~ == $HOME be true?


I want to disassemble a broken hair dryer (just to see what's inside), but I just found out it uses a weird tamper-proof screw I had never seen in my life. Trying to google for it doesn't help much; I still could not find its official name.  It's like a standard flat screw, where the central part has not been cut, and looks like this from above:    It looks a bit like an "H", so I tried looking for "H screw" and got a  Google , but I find very few of them, and they look mostly related to watches.  I find it appalling that Philips (the hair dryer manufacturer) needs to put such tamper-proof protection on such a common household appliance, but I suppose they have their legal reasons to do so. However, without knowing the name of the screw, I can hardly find where to buy a screwdriver for it!  If there is an official name for this screw, please enlighten me. I found a  on the Internet, but it seems to be small and related to watches. My screw is a "standard small appliance size".


Questions about radially open sets topology.

I'm understanding this topology through doing an exercise.  We say that a subset $U \subseteq \mathbb{R}^{2}$ is radially open if if for every $x \in U$ and every $u \in \Bbb R^2$ with $||u||=1$, there is an $\epsilon>0$ such $x+su \in U$ for every $s \in (- \epsilon, \epsilon)$. I already proved these sets are a topology for $\mathbb{R}^{2}$.  First question (this was not asked for the exercise) is how can I visualize this strange topology. I got a picture for my book but still don't catch it up.  Second question, if $T_{e}$ is the usual topology for $\mathbb{R}^{2}$ and $T_{r}$ is the radially topology, how do I prove that $T_{e} \subseteq T_{r}$ and $T_{r} \not \subset T_{e}$. As I dont understand the image of this topology I cannnot figure out the first contention also for the second I have only find here confusing examples.  Last question, I want to prove that for every circumference in radially plane has discrete topology as topological subspace. I think this was asked once and they always explain that this intersection gives the center of the circumference but dont really understand the steps to conclude this.  Any help will be aprecciated. Thanks!


I've been doing jmeter tests and have had a few OutOfMemoryExceptions, so I've bumped up the heap memory in JMeter. But now it seems I can't run anymore tests as it says I'm using 94.9% of 14Gb.  When I use df -h it says dev/sda1 is full  I was wondering if anyone can help me? I think it has to do with the JVM from the jmeter


Building the connection between cosine similarity and correlation in R

According to some articles (e.g. ) correlation is just a centered version of cosine similarity. I use the following code to calculate the cosine similarity matrix of the column vectors of a matrix X (slightly modified from ):  cos.sim <- function(ix)  {   A = X[,ix[1]]   B = X[,ix[2]]   return(t(A)%*%B/sqrt(sum(A^2)*sum(B^2))) }    n <- ncol(X)  cmb <- expand.grid(i=1:n, j=1:n)  C <- matrix(apply(cmb,1,cos.sim),n,n)   My question  Which modifications of the code above are needed to get the correlation matrix cor(X) instead of the cosine similarity matrix. I guess the changes are minimal but I can't see them at the moment.


What are some good techniques to make a rounded/beveled hole in a non-flat surface? e.g. something like the :    The Boolean Modifier and the Knife project tool work well, but they create uneven topology that is difficult to bevel.    Image from the blender wiki


How do I clean my boot partion using a live cd

I have an upgrade install of Ubuntu 16.04.1 which will not load the desktop, when I attempt some of the solutions I get an error gzip: stdout: No space left on device. My /boot partition is 449 MB and has many old kernel versions. I am currently using a Live CD while searching for solutions, how can I free up some space on the /boot partition?  Here is the output of a ls command on the mounted boot partition in a live cd session:   abi-3.13.0-67-generic abi-3.13.0-68-generic abi-3.13.0-70-generic abi-3.13.0-71-generic abi-3.13.0-73-generic abi-3.13.0-74-generic abi-3.13.0-76-generic abi-3.13.0-77-generic abi-3.13.0-79-generic abi-3.13.0-83-generic abi-3.13.0-88-generic abi-3.13.0-91-generic abi-3.13.0-92-generic abi-4.4.0-31-generic config-3.13.0-67-generic config-3.13.0-68-generic config-3.13.0-70-generic config-3.13.0-71-generic config-3.13.0-73-generic config-3.13.0-74-generic config-3.13.0-76-generic config-3.13.0-77-generic config-3.13.0-79-generic config-3.13.0-83-generic config-3.13.0-88-generic config-3.13.0-91-generic config-3.13.0-92-generic config-4.4.0-31-generic grub initrd.img-3.13.0-67-generic initrd.img-3.13.0-68-generic initrd.img-3.13.0-70-generic initrd.img-3.13.0-71-generic initrd.img-3.13.0-73-generic initrd.img-3.13.0-74-generic initrd.img-3.13.0-76-generic initrd.img-3.13.0-77-generic initrd.img-3.13.0-79-generic initrd.img-3.13.0-83-generic initrd.img-3.13.0-88-generic initrd.img-3.13.0-91-generic initrd.img-3.13.0-92-generic initrd.img-4.4.0-31-generic lost+found memtest86+.bin memtest86+.elf memtest86+_multiboot.bin System.map-3.13.0-67-generic System.map-3.13.0-68-generic System.map-3.13.0-70-generic System.map-3.13.0-71-generic System.map-3.13.0-73-generic System.map-3.13.0-74-generic System.map-3.13.0-76-generic System.map-3.13.0-77-generic System.map-3.13.0-79-generic System.map-3.13.0-83-generic System.map-3.13.0-88-generic System.map-3.13.0-91-generic System.map-3.13.0-92-generic System.map-4.4.0-31-generic vmlinuz-3.13.0-67-generic vmlinuz-3.13.0-68-generic vmlinuz-3.13.0-70-generic vmlinuz-3.13.0-71-generic vmlinuz-3.13.0-73-generic vmlinuz-3.13.0-74-generic vmlinuz-3.13.0-76-generic vmlinuz-3.13.0-77-generic vmlinuz-3.13.0-79-generic vmlinuz-3.13.0-83-generic vmlinuz-3.13.0-88-generic vmlinuz-3.13.0-91-generic vmlinuz-3.13.0-92-generic vmlinuz-4.4.0-31-generic


Let $f$ be a function $f:\mathbb{R}\rightarrow \mathbb{R}$ such that $f(x)f''(x)\leq 0$ for all $x\in \mathbb{R}$.

Let $f$ be a function $f:\mathbb{R}\rightarrow \mathbb{R}$ such that the derivative $f'(x)$ and all its successive derivatives exist everywhere and also $f(x)f''(x)\leq 0$ for all $x\in \mathbb{R}$. Let $\alpha$ and $\beta$ be two consecutive roots of $f(x)=0$. Prove that $f'''(\gamma)=0$ for some $\gamma \in(\alpha,\beta)$  I feel that the problem may not be true  I have been able to draw the curve of such a function..


Group of order 35 must have a normal subgroup of order 5 or 7 or both without using Sylow’s theorems

This was a previously asked question that only had answers referring to Sylow's theorem, which is not something I can use here. Let $G$ be a group, $|G|=35.$ We know that $G$ must contain an element of order $5$ and an element of order $7$.  (1) Prove that $G$ must have a normal subgroup of order $5$ or of order $7$ or both.   (2) Deduce that $G$ is isomorphic to $C_{35}$.  (1) Attempt: It is shown earlier in the question that if $\Omega$ is the set of subgroups of $G$ isomorphic to a subgroup $H\leq G,$ and $G$ acts on $\Omega$ by conjugation, then $$\text{Stab}(H)=G \iff H\; \text{is a normal subgroup}.(*)$$ Assume for contradiction $G$ has no normal subgroups of order $5$ or $7$. Take $g_1,g_2$ as order $5$ and order $7$ respectively, then $\langle g_1\rangle$,$\langle g_2\rangle \leq G$ are not normal. Now by $(*)$ we can find an element in $G$ such that conjugating $\langle g_1\rangle$ by it gives a subgroup of $G$, isomorphic to but distinct from $\langle g_1\rangle$. By Lagrange's theorem then, and noting the intersection of subgroups is a subgroup, these two order $5$ subgroups must have trivial intersection Similarly we can find two order $7$ subgroups with trivial intersection. And it is clear too that all non-identity elements in all four of these subgroups, of which there are $20$, are distinct. This leaves $14$ non-identity elements outside of these subgroups, but I am stuck here. I think if $G$ has no order $35$ element then noting the only non-negative integer solution to $4p+6q=14$ is $p=2,q=1$ shows that we can distribute these elements into two new distinct order $5$ subgroups and one new order $7$ subgroup, but I can't see how this would help. I'm sure I can complete this as a counting argument but I'm not sure where to go.


Does an input exist in cycles to measure how much light is hitting the object?

Say, I have a sphere, and I want the bright side to be one texture/shader and the dark side to be another texture/shader.  Is there any way to vary this based simply on how much light is hitting it?  I've done some work with dot products, but the best result I have involved a seem in the sphere where the test pattern changes abruptly; furthermore, there are a lot of assumptions about where everything is, among other problems.  Basically, I'm looking to change the material based on the shading itself (ie, if there were a single color, the changes to that color that cycles makes to describe the object is what I want to base the changes on.)  I'd post my work, but it's getting obscenely complicated and it only looks good from certain angles - (none of which are the camera angles, that was one of the cross products.)  Thanks in advance.


TexShop will not compile without trashing aux files after every error

I have a couple of LaTeX files with the same problem. If I produce an error, fix it, and then try to compile a pdf, I get the following error.  )Runaway argument? {{ ! File ended while scanning use of \@newl@ablel. <inserted text>                 \par l.90 \begin{document}   If I then click on the console or trash my .aux file, it compiles fine. Any thoughts on what is going on and how to prevent this annoying extra step?


Steam saying I am missing "libc.so.6", even though it is in my libraries folder

I a question like this has been asked before, but none of the solutions I found have worked, and I think my problem is different, because it's more like Steam not detecting the library. Exact error message:     You are missing the following 32-bit libraries, and Steam may not run: libc.so.6   When I try run sudo apt-get install libc6:i386, it returns this:  Reading package lists... Done Building dependency tree        Reading state information... Done libc6:i386 is already the newest version (2.23-0ubuntu3). You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  gcc-5-multilib : Depends: libc6-dev-i386 (>= 2.11) but it is not going to be installed  libc6-dev-x32 : Depends: libc6-dev-i386 (= 2.23-0ubuntu3) but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   I have tried apt-get -f install, which returns this error:  dpkg: error processing archive /var/cache/apt/archives/libc6-dev-i386_2.23-0ubuntu3_amd64.deb (--unpack):  trying to overwrite '/usr/include/bits', which is also in package libc6-dev-amd64:i386 2.23-0ubuntu3 Errors were encountered while processing:  /var/cache/apt/archives/libc6-dev-i386_2.23-0ubuntu3_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   It looks like my problem is that the file is there, but for some reason it is not detected by Steam.


How can an ISO be mounted in the terminal in the way that Ubuntu mounts an ISO by double-clicking the ISO file?

In Ubuntu 16.04, if I double-click on an ISO file, Ubuntu gets the volume ID, then mounts that ISO at a directory at /media/$USER/ with the volume ID as the name of the directory. It does this without any request for root permissions.  I want to replicate this behavior in the terminal. I don't want to go first parsing the output of isoinfo -d -i data.iso, then granting root permissions to the user so that they then run mkdir in /media/ followed by running the mount command etc. I want to replicate what Ubuntu is actually doing and I want to replicate it without asking the user for root permissions.  How might this be done?


I used this and others in my Codeigniter website,  ⇾   I encode and decode using HTML entities.  I declared this:   <meta charset="utf-8">   in my header but I kept getting this  â‡¾    any solution?


Is there a command line way to install Telegram?

I have tried this:  sudo add-apt-repository ppa:atareao/telegram sudo apt-get update sudo apt-get install telegram   But no gain it provides an older version of Telegram. So I thought to ask a new question on how to install the latest version of Telegram in Ubuntu 16.04


How does dark matter halo outside a galaxy help to explain galaxy rotation curve?

How does a   outside a galaxy help to explain a ?  Suppose for simplicity we use a model of a star rotating about a more massive star in a fixed circular orbit. For another star at larger radius, the velocity should be smaller but observationally for spiral galaxies, the opposite happens (moves at even more speed or at least at the same speed as the closer star).  People hypothesize that dark matter halo may be present “surrounding” the system (i.e., halo exists outside the system) to account for such observation. I feel that exactly the opposite should be the case that is, dark matter halo should be inside the galaxy rather than outside. Reason being, if dark matter is outside the galaxy then the effective gravitational pull on the rotating star towards the center will be reduced due to outward attraction on the star exerted by dark matter existing outside. Thus, its speed of rotation should be reduced; but we observe the opposite. So how does dark matter halo "surrounding" a galaxy help to explain galaxy rotation curve? Where am I making mistake in argument?


Prove $\tan\big(\frac{\pi}{2} -\theta \big) = \cot \theta$

$$\tan\left(\frac{\pi}{2} -\theta \right) =  \cot \theta$$  I can prove this by changing into $\cos$ and $\sin$  But I want to know if it is possible to prove it using relation given below. If not why ? $$\tan\left(\frac{\pi}{2} -\theta \right) =\frac{ \tan\frac{\pi}{2} -\tan\theta}{1+ \tan\frac{\pi}{2}\tan\theta} $$


Which is more appropriate to use?      I graduated at Harvard university    Or     I've graduated at Harvard university


Can I assign a lambda to itself without infinite recursion?

I am trying to solve a  and one thing I didn't realize earlier came up: public class Kata {     private static int y(int x) => 2 * x + 1;     private static int z(int x) => 3 * x + 1;      private static int self(int x) => x;      public static int DblLinear(int n)     {         Func<int, int> lowerBound = self;         Func<int, int> upperBound = self;          int result = 1;          for (int i = 1; i <= n; ++i)         {             lowerBound = (x) => y(lowerBound(x)); // [1]             upperBound = (x) => z(upperBound(x)); // [2]         }          ...     } }  My intention was to calculate y(y(y(y(... (x)))) and z(z(z(z(... (x)))) iteratively, but lowerBound and upperBound do not appear to function as actual variables; they work more like delegates here. When I run the program, a StackOverflowException is thrown. Is there any way I can accomplish this?


Should I use multi-label classification?

I have a classification problem with 2 classes (positive and negative). Usually, in such classification problems, all the samples will be labelled either 'positive' or 'negative'. In my dataset, some of the samples possess a combination of both positive and negative characteristics. Formally, if the dataset is $x$, then,      $x=x_1 \cup x_2 \cup x_3$   where $x_1$ is the set of all positive samples, $x_2$ is the set of all negative samples and $x_3$ is the set of samples that contain the characteristics of both the classes. As far as I could think of, this situation could be handled in 2 ways,   Ignore $x_3$ (samples that contain characteristics of both classes) and treat the problem as a traditional binary classification. Label the samples in $x_3$ with both labels (positive & negative) and consider this as a multi-label classification problem.   I wish to follow the second option, as it is more natural choice. The reason being, ignoring some samples from the dataset gives me a feeling of manipulating the dataset artificially which may affect the performance of the classifier in the real world scenario. In this context, I have the following questions,   Is it correct to treat this a multi-label classification problem. If so, is the intuition which is explained in the previous paragraph correct? Is there any other learning paradigm that can handle this scenario? If so, please provide reference to relevant literature.


Null Pointer Exception when using PDF Viewer Lib

I encounter the following error when I using the AndroidPdfViewer library. and this is my encounter the error:  FATAL EXCEPTION: main                                                                      Process: app.com.application, PID: 16559                                                                      java.lang.NullPointerException: Attempt to invoke virtual method 'com.github.barteksc.pdfviewer.PDFView$Configurator com.github.barteksc.pdfviewer.PDFView.fromStream(java.io.InputStream)' on a null object reference                                                                          at app.com.application.activity.Main2Activity$RetrievePDFStream.onPostExecute(Main2Activity.java:65)                                                                          at app.com.application.activity.Main2Activity$RetrievePDFStream.onPostExecute(Main2Activity.java:38)   My Code :  public class Main2Activity extends Activity {  String URL_PDF = "http://192.168.1.103/android_login_api/PDF/1G.pdf";     PDFView pdfView;      @Override     protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main2);      // view pdf from url     new RetrievePDFStream().execute(URL_PDF);  }   private class RetrievePDFStream extends AsyncTask <String, Void, InputStream>{      @Override      protected InputStream doInBackground(String... strings) {          InputStream inputStream = null;          URL url = null;          try {              url = new URL(strings[0]);          } catch (MalformedURLException e) {              e.printStackTrace();          }           try {              HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();              if (httpURLConnection.getResponseCode()==200){                   inputStream = new BufferedInputStream(httpURLConnection.getInputStream());              }          } catch (IOException e) {              return null;          }          return inputStream;      }        @Override      protected void onPostExecute(InputStream inputStream) {          pdfView.fromStream(inputStream).load();      }      }  }   Please guide me to fix the problem, Thank You. I also had another question: is it possible to use this method Volley instead of AsyncTask?


Do you say I´ll arrive in the first week of July? or on the first week of July?


Failed to log in: the authentication servers are currently down for maintenance

So once a month I'm having this problem where I can't connect to any servers with 1.8 but I can with 1.9, this makes it so I can't play on the servers that are only for 1.8.  How can I fix this?


Unable to send email using "SMTP Authentication Support" module

I was working on a project where i  used "SMTP Authentication Support" module to send emails. The authentications i provided were my personal gmail account details, It was working fine. Now when i am entering the site admins account details its displaying "Unable to send e-mail. Contact the site administrator if the problem persists." error. It also says that "SMTP Error: Could not authenticate." Can anyone let me where i am going wrong.


Proof by induction involving symmetric groups

I am aware that i have posted this question before, but the comments i received did not really help silly old me. So i would appreciate it if someone can walk me through some parts of the problem. I have revised my attempt from the previous post, accounting for the comments i have received as i understood them.     Let $n>1$ be a natural number. the m-cycle   $\sigma=(a_1,a_2,a_3,\dots,a_m)$ denotes a permutation in $S_n$ where   $\sigma(a_1)=a_2,\sigma(a_2)=a_3,\dots, \text{ and }\sigma(a_m)=a_1$.      Prove by induction on $k \geq 1$ that if $k+i\equiv j (mod\text{ m})$, then $\sigma^k(a_i)=a_j$   whenever $1\leq i \leq m$ and $1\leq j \leq m$.   Pained Attempt :  Let $n>1$ be a natural number. the m-cycle $\sigma=(a_1,a_2,a_3,\dots,a_m)$ denotes a permutation in $S_n$ where $\sigma(a_1)=a_2,\sigma(a_2)=a_3,\dots, \text{ and }\sigma(a_m)=a_1$.  [Base Step]  For the base case,$k=1$, assume that $1+i\equiv j (mod\text{ m})$ and prove that $\sigma^1(a_i)=a_j$ whenever $1\leq i \leq m$ and $1\leq j \leq m$.   Since $1+i\equiv j (mod\text{ m})$ then $j \equiv 1+i (mod\text{ m})$ and $m | j-(1+i)$ hence $j = mh+i+1$ for some $h \in \Bbb{Z}$.   [case:$1 \leq i \lt m$]  Since $j=mh+i+1$ then $a_j=a_{mh+i+1}$. By assumption $\sigma(a_{mh+i})=a_{mh+i+1}=a_j$.  I am not sure how to proceed further here..  I thought: With $1 \leq i \lt m$ and mh+i+1 being constrained to lie between 1 and m given the definition of the m-cycle, this implies that h must be 0 (?).Therefore $\sigma(a_{m(0)+i})=a_{m(0)+i+1}=a_j$ and $\sigma(a_{i})=a_{i+1}=a_j$ as required (?)  ...this feels iffy.  [case: $i=m$]  Since $j=mh+i+1$ then $a_j=a_{mh+m+1}$ and $a_j=a_{m(h+1)+1}$ . By assumption $\sigma(a_{m(h+1)})=a_{m(h+1)+1}=a_j$.  I am not sure how to proceed further either..  Any help would be much appreciated.


How to construct a continuous function from a non compact metric space to R that is unbounded?

There is a theorem that states that every continuous function from a compact metric space to R is bounded however, the converse is not true, but I am not sure how to construct such a function. My idea is to start with a countable subcover that has no finite subcover. Since we can enumerate each subcover U1, U2, U3..., I was thinking of mapping each element in the subcover equal to its index, but I'm not sure if this function is continuous.


Does anyone know a book about Rune Casters/Masters?

When I was in America, I began reading a book series. It was a fantasy fiction series about some people who could use other peoples attributes, like their beauty or their intelligence by tattooing a rune on the pair  (so one person would have the rune to take beauty and someone else would have the rune to give beauty and someone would cast a spell or something?)  There were also people who thought it was wrong to take from other humans so they took their attributes from dogs. (Like sight, strengh, speed, smell etc)  It's been bugging me for years and any searches for "rune casting" or "rune masters" just turns up books on how to read runes. Any one got any ideas?


Alignment hoirzontal instead of vertical

I'm working on an assignment for school and we're supposed to make a script that counts to 100 in blocks of 10. So you would get number 1 to 10 in row 1, from left to right. In row 2 you'd get 10-20, from left to right, and so on.  I've wrote some part of the script but I can't figure out how to allign it from left to right, instead of top to bottom. This is what I've got so far:  def number(count):  while count!=11:     print(count)     count=count+1; number(0)


jQuery - setting the selected value of a select control via its text description

I have a select control, and in a javascript variable I have a text string.  Using jQuery I want to set the selected element of the select control to be the item with the text description I have (as opposed to the value, which I don't have).  I know setting it by value is pretty trivial. e.g.  $("#my-select").val(myVal);   But I'm a bit stumped on doing it via the text description. I guess there must be a way of getting the value out from the text description, but my brain is too Friday afternoon-ed to be able to work it out.


When using redirect() in Flask, HTML is written to Console

So I've been working in Flask and ran into an irritating problem. I'm creating a website and using the redirect function the website doesn't switch pages. Each place I'm attempting to go to can render_template() when not called via redirect. Here's my code (yes, the hashed_password isn't hashed and I should probable redirect to next, but these are are problems for another day):  @app.route('/logIn',methods=['Get', 'Post']) def logIn():     _name = request.form['inputName']     _password = request.form['inputPassword']     # _hashed_password = bcrypt.hashpw(_password, bcrypt.gensalt( 12 ))     _hashed_password = _password      conn = mysql.connect()     cursor = conn.cursor()     cursor.execute("SELECT * FROM tbl_user WHERE user_name = '" + _name + "'")      user = cursor.fetchone()     print(user[0])      if len(user[2]) is not 0 and user[3] == _password:          active_user = User(user[0])         login_user(active_user)         return (redirect(url_for('home')))     else:          return json.dumps({'message': 'Username or Password not correct'})   @app.route('/Home') @login_required def home():     return render_template("home.html")   This all works with a html and js background. The HTML doesn't have any code, only contains the button to be clicked (though if it'll help I can post the html). The JS looks like this for the login button:  $(function() {     $('#btnLogIn').click(function() {          $.ajax({             url: '/logIn',             data: $('form').serialize(),             type: 'POST',             success: function(response) {                 console.log(response);             },             error: function(error) {                 console.log(error);             }     }); });   });  Finally, the output spits back the html for the Home page, the one I want to be rendering in the browser (this is the output):  <!DOCTYPE html> <html lang="en">   <head>     <title>Python Flask Bucket List App</title>       <script src="static/js/jquery-3.3.1.min.js"></script>       <script src="static/js/logout.js"></script>   </head>    <body>    <form class="form-signout">        <button id="btnLogOut" class="btn btn-lg btn-primary btn-block" type="button">Log Out</button>    </form>   </body>  </html>   I've been looking everywhere. Also, adding /Home after the local host domain calls the same GET as the one called after clicking the button and successfully loads the page. If anyone knows how to do this with loading the "next" url, that would be even better.


Create desktop map explorer application using QGIS?

I need to create a map/data-explorer application that works offline (no internet connection), and I am trying to find out if anyone has developed desktop applications with QGIS similar to how one might ?


Granting access to all tables for a user

I'm new to Postgres and trying to migrate our MySQL databases over.  In MySQL I can grant SELECT, UPDATE, INSERT, and DELETE privileges on a low privileged user and enable those grants to apply to all tables in a specified database.  I must be missing something in Postgres because it looks like I have to grant those privileges for each table one at a time.  With many databases and hundreds of tables per database that seems like a daunting task just to get off the ground.  In addition, once a database is in operation, adding tables happens frequently enough that I wouldn't want to have to grant permissions each time unless absolutely necessary.  How is this best accomplished?


I have a Schengen visa but my UAE Residence visa cancelled. Can I still travel then?

I'm a Philippine passport holder.  I have applied recently for a Schengen and UK visa and was approved.  Unfortunately before my travel dates came my UAE residence needs to be cancelled as I was terminated.    Can I still travel to Europe since I have a visa with them and be back to UAE on a visit visa.  Will all these be possible to do?


PHP and sql query coding utf 8 german letters

I have problem with getting records from database when I have words with German letters in SQL query, when I do it in phpAdmin it gives 88 rows with results, when I want to execute the same query but in php code it gives me bool(false). In db I use utf8_bin. What is wrong? $getPapers = mysql_query("SELECT * FROM swt_pubs WHERE column LIKE '%Aß%' ORDER BY id DESC LIMIT 10"); echo $getPapers; while ($papers = mysql_fetch_object($getPapers)) {     echo "string";     echo convertToUTF8($papers->content); } var_dump($papers);?>  Results which I get:  Resource id #6 bool(false)  Edit 1: I have this coding of page: <meta http-equiv="Content-Type" content="text/html;charset=utf-8">  Edit 2: function convertToUTF8 ($string)         {         return str_replace ('Ã„', '&#196;',                str_replace ('„', '&#132;',                str_replace ('“', '&#147;',                str_replace ('–', '&#150;',                str_replace ('', '&#173;',                     str_replace ('È', '&#200;',                         str_replace ('É', '&#201;',                             str_replace ('Ö', '&#214;',                                 str_replace ('Ü', '&#220;',                                     str_replace ('ß', '&#223;',                                         str_replace ('ä', '&#228;',                                             str_replace ('è', '&#232;',                                                 str_replace ('é', '&#233;',                                                     str_replace ('ö', '&#246;',                 str_replace ('ü', '&#252;',                     str_replace ('@', '&#64;',                         str_replace ('Ã?', '&#220;',                             str_replace ('\"', '"',                             str_replace ("\'","'",                                 ersetzeBbCode ($string)                                     ))                                 ))                             )                         )                                                                 )                                                             )                                                         )                                                     )                                                 )                                             )                                         )                                     )                                 )                             )              ))             );         }


Identification of the polynomial given symmetric relations

Let $p(x)$ be an eighth degree polynomial. Given that:  $p(1) = 1$, $p(2) = 1/2$, $p(3) = 1/3$, .... $p(9) = 1/9$  Find the value of $p(10)$. I tried to approach this by taking $h(x) = p(x) - 1/x$ but then $h(x)$ won't be a polynomial. I tried to manipulate the equation but I failed to find anything helpful. I have found a relation between the coefficients and some values; 9 equations and 9 variables but it would be too cumbersome to solve.   Some guidance would be appreciated. Thanks! (Sorry for the poor title; if anyone can improve it please do so)


How to open Internet Explorer in "desktop mode" and not the "Windows UI mode" in Windows 8.1

I just needed a new laptop and Windows 8 came with it...  One of the issues we're frustrated most about is those applications that open in the "Windows UI" mode (formerly known as Metro-style). Such as Internet Explorer.  We hate the "Windows UI" mode for Internet Explorer because we   Don't see tabs Can't just close it normally (I know, there are other ways, but we prefer the close icon) Internet Explorer switches to "suspended" mode when toggling applications which causes audio to stop running   I don't seem to be able to start Internet Explorer in "desktop mode", while there are supposed to be two modes possible (see  and ).  Internet Explorer is still the default browser.  I read in other questions ( and ) that Metro style is only possible when it's the default browser. But I actually can't succeed in the reverse: Is desktop mode possible at all when Internet Explorer is the default browser?.


Why do no moderators appear under the moderators tab on Meta Stack Exchange?

When I click on the "moderator tab" at the user page on , I get an empty list. This is not the case on other SE-sites (I have tried Biology SE, Stack Overflow and Academia SE).  Screenshot:   I get the same result using both Firefox 38.0.5 and Internet Explorer 11.


Why are filenames that start with a dot hidden? Can I hide files without using a dot as their first character?

Initially I thought it was a coincidence, but now I see there's even  for it: all hidden file names start with a dot. Is this a convention? Why was it chosen? Can it be changed? Or in other words (as a related question @evilsoup suggested that implies the answer to a bunch of others): can I hide files without renaming them (using . as the first character of their name)?


Calculate limit or prove it does not exist

$$  \lim_{x\to \pi}\frac{\cos(\frac{x}{2})}{\pi^2-x^2}  $$  I thought to change $x$ with $t$ like this:  $$  \lim_{t\to 0}\frac{\cos(\frac{t+\pi}{2})}{\pi^2-(t+\pi)^2}  $$  Now I'm not sure how to continue.. Also I'm not allowed to use l'hopital rule or derivative at all. Thank you


Exchangeable Swing Element - how to implement?

I am faced with the following situation: My GUI needs a Panel with some special methods (Adding a message to display, adding an image...). Easy so far. Now, this element is supposed to be exchangeable from the outside! One version has a pink background, one has a purple one, one is upside down, to name some random examples. My basic idea was to define an abstract class extending JPanel,  with the required methods defined as abstract methods as well. The question that now keeps me stuck is: where do the implementations belong? I cannot have a jar implement an abstract class from the main apllication, and then have the application use that jar. That idea alone sounds totally broken!  So, how do I solve this properly? I feel like I am missing something obvious here...  EDIT: Plugin is the word I was missing! Marked this as duplicate, the linked answer tells me exactly what I was lookign for :)


We want to visit Canada on a short-term visitor visa for tourism. We are a family of 4 but we have a family friend traveling with us. I will financially support all 5 of us. While applying for the VISA online and filling the questionnaire, it asks for additional family members traveling with me and their documents so shall I include our family friend in the same list? If not, how do we process it otherwise?  I am not sure how it works with Canada but all 5 of us applied for a USA VISA in the same way in a single application. I just had to mention the people traveling with me, we applied as a group and went for interview together. We were granted the VISA successfully.


We know that sunlight or light incident from sun on earth is white in color or have all frequencies of light in visible electromagnetic spectrum. However I have read that sun is a yellow medium star, and satellite pictures indeed show it is $yellowish-orange$ in color. Why is this case that sun is deemed as a yellow star but have white light incident from it? Is it due to our atmosphere or something else?


What features should one look for when selecting a flash?

I have been thinking of getting a flash to improve my low light photography (particularly indoors). However, there seem to be a number of different models available at similar price points (budget of INR 8,000-12,000 ~$150-250). What features and functionality should I look for to choose a suitable flash?  I'm using a Canon 550D with the 18-55mm IS & 55-250mm IS lenses. Metz seems to be one of the brands easily available in India (beside the OEM flashes). Currently, I am considering the Metz 36 AF-5, 44 AF-1 and 50 AF-1, which seem to be considerably cheaper than their Canon counterparts.


I need to prove that there are infinitely many numbers  of the form $x = 111....1$ such that $31\mid x$  what I tried - I wrote x as   $\sum_0^{n-1} 10^i$  I know that $(10,31) = 1 $  now I'm stuck .. any help will be appreciated


Restricting the awk output of df sum to 2 decimal points

I have a script to calculate the cumulative capacity in all the servers.  for i in `cat servers` do ssh user@$i "df -t xfs --total | grep total"; done > capout.txt awk -vDT="Capacity" '         {sum2 += $2          sum3 += $3          sum4 += $4          sum5 += $5         } END     {GIGA=2^30           print DT,"\t" sum2/GIGA,"\t" sum3/GIGA,"\t" sum4/GIGA ,"\t"  sum3/sum2*100         }' capout.txt >> capacity.csv   Script works fine and i am getting the output as below.  Capacity   1047.43         439.4   608.032         41.9502   However i do not want to have the 3 trailing decimal points, I just need to restrict to one or two decimal points here.


What is tilda character in c# constructor?

In doing a code review I came across this:  public class ClassTilda {     ~ClassTilda(){             //code     } }   Why is this building and what is that tilda?  Can you provide a reference?


How to replace Contains() with IndexOf()

I'm using the following line of code to match search word in my data list. But Contains is case-sensitive if I search for "search" it doesn't match with "Search" or "seArch".  What are my alternatives to Contains? How Can I replace it with IndexOf?  IEnumerable<Compound> allCompounds = _context.Compounds.ToList(); IEnumerable<Compound> filteredCompounds; if (!string.IsNullOrEmpty(param.sSearch)) {     filteredCompounds = allCompounds              .Where(c => c.CompoundName.Contains(param.sSearch)                          ||                          c.RI.Contains(param.sSearch)                           ||                          c.MolecularWeight.Contains(param.sSearch)                          ||                          c.MolecularFormula.Contains(param.sSearch)                          ); }


I bought myself a RAM memory upgrade. Specifically (Corsair Ddr3 8gb 1600mhz Cmso8gx3m1b1600c1). My laptop is Dell Lattitude E6440. Would it fit? Been reading that my laptop takes ddr3L, but this is just ddr3. Just noticed it :7. So will it even work? I heard the main difference is voltage, right?  Thanks, EB.


Let S be the set of all real numbers in the interval (0; 1) whose decimal expansions contain only 0's, 4's and 8's. Prove that S is uncountable.

I just prove $$S_1=\{0.4,0.8\}$$ $$S_2=\{0.04,0.08,0.44,0.48,0.84,0.88\}$$ ... So I can calculate the number of elements in $S_n = 2 \times 3^{n-1}$  I just prove it is countably infinite.


Design patterns or best practices for shell scripts

Does anyone know of any resources that talk about best practices or design patterns for shell scripts (sh, bash etc.)?


Oneboxing a onebox from a different chat server generates a weird URL

So if you try to onebox a onebox from a different chat server, . Basically, it generates this URL:    Now, obviously that isn't right. I've also tested this , and I'm assuming it's broken on chat.SO too. Can this be fixed?


Diagonal entries are zero, others are $1$. Find the determinant.

$\det\begin{vmatrix} 0 & \cdots & 1& 1 & 1 \\ \vdots & \ddots & \vdots & \vdots & \vdots \\ 1 & \cdots & 1 & 1 & 0 \end{vmatrix}=?$  Attempt:  First I tried to use linearity property of the determinants such that $$\det\binom{ v+ku }{ w  }=\det\binom{v  }{ w  }+k\det \binom{ u }{ w  }$$  $v,u,w$ are vectors $k$ is scalar.  I have tried to divide it into $n$ parts and tried to compose with sense but didn't acomplish.  Second I tried to make use of "Row Reduction" i.e. adding scalar multiple of some row to another does not change the determinant, so I added the all different rows into other i.e. adding $2, 3,4,\dots,n$th row to first row and similarly doing for all rows we got   $$\det\begin{vmatrix} 0 & \cdots & 1& 1 & 1 \\ \vdots & \ddots & \vdots & \vdots & \vdots \\ 1 & \cdots & 1 & 1 & 0 \end{vmatrix}=\det\begin{vmatrix} n-1 & \cdots & n-1& n-1 & n-1 \\ \vdots & \ddots & \vdots & \vdots & \vdots \\ n-1 & \cdots & n-1 & n-1 & n-1 \end{vmatrix}=0$$  The last determinant is zero (I guess) so the given determinant is zero?  I don't have the answer this question, so I am not sure. How to calculate this determinant?


$\mathbb{R}P^4$ and $\mathbb{R}P^6$ do not admit fields of tangent $2$-planes

See the related question . This is the second part of question 4-C in Milnor and Stasheff's book on characteristic classes. In the solution to the first part, we rely on the fact that having a field of tangent $1$-planes allows us to split the tangent bundle into a direct sum. It doesn't seem like this should be true for a field of tangent $2$-planes (otherwise the question wouldn't just be asking about $P^4$ and $P^6$), so I'm not sure exactly where to start.  edit: actually, since $P^n$ can be given a Riemannian metric, any subbundle should be a Whitney summand; this doesn't answer the question as to why they only ask for $P^4$ and $P^6$ though, so I'm still confused.


But I don't want "reduced advertising" when I get 200 Rep!

One of the "benefits" of earning 200 rep points is that fewer ads are displayed to you. Instead of seeing three zones (Leaderboard Top, Leaderboard Bottom, and Sidebar), you see only one (Sidebar).  Now I put "benefits" in quotes because I personally don't consider less advertising (especially on SO) to be beneficial. Of course, as the "ad guy", I really don't care because the loss of impressions are statistically negligible, but as a member I feel that I'm missing out on something.  We work hand-in-hand with each sponsor to make sure their ads are high quality and relevant, and we won't even talk to companies with a product/service that we know is a poor fit. And now that there's no more AdSense, that's the only thing we see.  There are so many awesome products/services that I've found through relevant ads, most of which solved problems I didn't even realize I had (or were solvable). , for example, has very recently "changed my life". And of course, there's no other way I'd find out about these, because I don't spend a whole lot of time reading reviews, etc.  So long story short... I think the "reduced advertising" thing should be changed to work as follows:      On the User Profile page, there would be a Checkbox that reads "Show Reduced Advertising". The Checkbox remains hidden until the member reaches 200 rep. Upon reaching 200, the box gets automatically checked.   Basically, it would work exactly the way it did before, except you get the option to turn off reduced advertising.  And yes, of course I'm biased. But still, Good ads are are a Good Thing.


I am working with time series, which is not stationary. I apply the differencing and log transformation to make my data stationary.  I forecast one year ahead forecast and check the accuracy of the model by retransforming it into its original form, but fail to obtain the required result. I can explain my question with the help of a simple example:     data <- c(10.45,45.6,33.67,32.12,76.34,12.3,23.5,13.76,35.78,98.45,77.88)     ac <- diff(log(data))     ad <- 10.45 + diffinv(exp(ac))  so ad= c(10.45000 ,14.81364, 15.55201, 16.50598, 18.88269, 19.04381, 20.95438, 21.53991, 24.14020,26.89174, 27.68280)


Lets say I have a siccative object that’s attached to a rope and it’s moving in a vertical circular motion around some circumcenter. If along the motion the rope will happen to reach maximum tension, intuitively it’ll tear, but will it? If it’ll tear the object will proceed at the direction of its velocity? Thanks for assuring that, and if it’s wrong thanks for correcting me


How to substring a number out of a string field using Python field calculator in ArcGIS?

Using ArcGIS Desktop 10.7 I want to substring numbers as text out of a string field into a new string field with field calculator so that I can use them for layer symbology. The field contains highway names such as 'I- 280' and 'State Rte 25' and I want only the '280' and '25' for a new field. Is there a Python conditional statement I can use that will substring the number regardless of digit length, placement (end or between text, eg, "State Rte 25 Bus")?


Apache could not reliably determine server

Apache cannot fully determine domain name when I tried restarting after install.  I get this error;  $ sudo /etc/init.d/apache2 restart Restarting web server config apache2 apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName.   Why am I seeing 127.0.1.1? I have tried saving ServerName localhost into my /etc/init.d/apache2 but it keeps redirecting me to Google search page every time I type phpmyadmin.  Will appreciate any expert help.


Why is DNS apparently involved in typing "dir" on Windows 10?

For complicated reasons, I have been forced to make an identical copy of cmd.exe and rename it to cmd-2.exe, which I put a shortcut to in the Taskbar. The reason is purely to have them "grouped" in different "taskbar groups", and nothing else.  Sometimes, I forget about this, and to open a new cmd.exe, I simply middle-click that Taskbar icon to open a new cmd.exe. Then I type a command such as "dir", and then it spits out a bunch of nonsense, including:  DNS bad key.   This only happens if I accidentally use the cmd-2.exe. Not if I open the "real" cmd.exe. So it's not a "practical" problem.  However, I wonder why that message is ever printed at all. It's apparently failing to do some kind of DNS lookup or something? Why is DNS involved at all with me typing "dir" to list files in my local computer? I have no network set up, no "cloud drives", nothing like that whatsoever. It scares me that (apparently) there are DNS queries being made when I type "dir".  Or maybe "DNS bad key" refers to something completely unrelated to the Domain Name System? I don't know what a "bad key" would even be in that context...


A nonsplit short exact sequence of abelian groups with $B \cong A \oplus C$

A homework problem asked to find a short exact sequence of abelian groups $$0 \rightarrow A \longrightarrow B \longrightarrow C \rightarrow 0$$ such that $B \cong A \oplus C$ although the sequence does not split. My solution to this is the sequence  $$0 \rightarrow \mathbb{Z} \overset{i}{\longrightarrow} \mathbb{Z} \oplus (\mathbb{Z}/2\mathbb{Z})^{\mathbb{N}} \overset{p}{\longrightarrow} (\mathbb{Z}/2\mathbb{Z})^{\mathbb{N}} \rightarrow 0$$ with $i(x)=(2x,0,0,\dotsc)$ and $p(x,y_1,y_2,\dotsc)=(x+2\mathbb{Z},y_1,y_2,\dotsc)$.  My new questions:   Is there an example with finite/finitely generated abelian groups? If the answer to (1) is negative, will it help to pass to general $R$-modules for some ring $R$?


Frying fish without it falling to shambles

How on earth do I pan fry fish without it turning to hell?  For the fish: Stainless steel pan Oil heated until it sizzles when droplets of water are thrown in Plain fish, skin side down first Try and flip, it falls apart...    Any advice on this?


Can circumcision cause childhood masturbation?

Before I start, let me say I hope this question isn't marked as seeking personal medical advice because I'm not asking for medical advice, and even though I talk about my personal experiences, I just want to know if circumcision can lead to early childhood masturbation.  I was circumcised when I was about 3 or 4 and I can't remember at which age I started masturbating so my guess is that it started right after that (very early). For as long as I can remember, I've always had a sensetive penis and I think that led to early masturbation. I could always feel slight stimulation whenever I lied down towards the bed.  Also I wonder if this has anything to do with being "cut tight".


Testing in Python - how to use assertRaises in testing using unittest?

I am trying to do a simple test in Python using unittest, to see if a class throws an exception if it gets an unsuitable input for the constructor. The class looks like this:  class SummaryFormula:     def __init__( self, summaryFormula):         self.atoms = {}         for atom in re.finditer( "([A-Z][a-z]{0,2})(\d*)", summaryFormula):             symbol = atom.group(1)             count = atom.group(2)              if pocet != "":                 self.atoms[ symbol] = int(count)             else:                 self.atoms[ symbol] = 1   My test is following:      class ConstructorTestCase(unittest.TestCase):       def testEmptyString(self):         self.assertRaises(TypeError, ukol1.SummaryFormula(), "testtest")      if __name__ == '__main__':       unittest.main()   All I want is the test to fail, meaning that the exception of unsuitable input for constructor is not handled.   Instead, I get an error: __init__() takes exactly 2 arguments (1 given).   What am I missing? What is the second argument I should specify?  Also, what type of Error should I use to handle exception that an input not matchable by my regexp was passed to the constructor?  Thank you, Tomas


Why do the Avengers struggle so much against Thanos in "Endgame", when they managed to resist him in "Infinity War" in a supposedly worse situation?

When Thanos fights the Avengers in Infinity War, he always has the Power Stone because that's the first he collected. So he has been fighting with increased power, yet some of the Avengers were able to resist him. However, in Endgame the same people are fighting him all at once, but can barely resist. In Infinity War, Wanda was destroying the Mind Stone with one hand, while pushing Thanos back with the other hand. And she actually did destroy that Infinity Stone with one hand, so she was using so much energy on that mission and wasn't fighting back Thanos in full power. But in Endgame, even using both her hands, she is not strong enough to push him back for more than 3 or 4 seconds. In Infinity War, Captain America, merely a human with strong muscles, can fight Thanos (who had just thrown a moon on Iron Man!) and resist against his punch for some seconds. Meanwhile, Captain Marvel uses her photon blast and superhuman strength to fight him hand-to-hand. Remember that she can carry a spaceship on top of her head all the way from nowhere in space to Earth, and can destroy spaceships just by flying really fast towards them, and doesn't get killed while doing so. Which is faaaaar more that what Steve is capable of, but Thanos throws her like an apple. Or the moon he threw on Tony. My point is, . But we've seen in Infinity War that some heroes can stand against him while he has the Power Stone. Yet in Endgame, they are no match for Stone-free Thanos. P.S. I did not ask why Thanos is strong. Read the question before marking it as duplicate, please.