I was puzzling over this question that a friend suggested to me. I have come up with no definite answer. What I thought was that:   $x/x$ is $1$ and  $x/0$ is UNDEFINED (or some people say it's $\infty$)   To explain this you need some weird quantum mathematics. When I scoured the internet for answers, all I could find was exactly what I found myself. Does anyone have a definitive answer (even if it's just definitely impossible).
I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it.
Which answer is correct?       Tony _______to have children until his little daughter was born. After   she won his heart, he decided he wanted a big family.       A. didn't want.   B. hadn't wanted.   This is a multiple choice question from the Understanding and Using English Grammar Workbook 3rd edition by Betty Azar. To me, both answers are correct as I cannot see the diffrence. Please show me the wrong option to delete. How do I define custom web.config sections with potential child elements and attributes for the properties? The web applications I develop often require co-dependent configuration settings and there are also settings that have to change as we move between each of our environments. All our settings are currently simple key-value pairs but it would be useful to create custom config sections so that it is obvious when two values need to change together or when the settings need to change for an environment. What's the best way to create custom config sections and are there any special considerations to make when retrieving the values? Logo Pack - What should I include? What files should i put in a logo pack to give to clients? Should I put small, medium and large version of my logo as well as the vector file. How can I make up for weak grades while applying for a masters? I feel I've received poor grades in my bachelor's degree in Mechanical Engineering - Second Class Second Division as per UK grading system. Having finished my bachelors in the UK I wish to enroll into a masters program in Systems or Mechanical Engineering in the US. I am currently employed by a logistics company in Dubai.   How can I improve my chances of getting into a grad school in the US with what I consider as poor grades? What other factors can strengthen my application? Does $E = mc^2$ apply to photons? Photons are massless, but if $m = 0$ and , then $E = 0c^2 = 0$. This would say that photons have no energy, which is not true.  However, given the formula $E = ℎf$, a photon does have energy as $ℎ$ is a non-zero constant and photons with a zero frequency do not exist.  What am I missing here, or does the famous formula not apply to photons? Where to find or how to make a frame like  below picture with optional width and height? The question I want to ask is related to the answer of this question:  .   My aim is to separate my bibliography into two parts : one part for a personnal bibliography, and a second one for the regular bibliography.  To do that, I use the technique of the post I cited :  \documentclass{article} \usepackage[T1]{fontenc} \usepackage[french]{babel} \usepackage[style=alphabetic,maxnames=6,natbib=true]{biblatex} \bibliography{biblatex-examples}  % Variants of each could be added \newcommand{\firstname}{Donald~E.} \newcommand{\lastname}{Knuth}  \DeclareBibliographyCategory{byname}  \DeclareIndexNameFormat{byname}{% Test could be refined   \ifboolexpr{ test {\ifdefstring{\lastname}{#1}}            and test {\ifdefstring{\firstname}{#3}}               } {\addtocategory{byname}{\thefield{entrykey}}} {}}  \AtDataInput{%   \indexnames[byname]{author}}  \begin{document}  \section{Knuth's books}  \begin{refsection}  \nocite{*}  \printbibliography[category=byname,heading=none]  \end{refsection}  \section{Not Knuth's books}  \printbibliography[notcategory=byname,heading=none] \end{document}   The problem is that only the second bibliography appears, and when I remove the refsection, then all the bibtex entries of my input files are printed, separated as they should.  EDIT: the aim is to have all publications (even the ones not cited) by author knuth in the first section and all the other cited publications in the second one. Can't finish registration in Stackoverflow.ru I have an account on Stack Overflow and also on Russian Stack Overflow. I can ask questions on Russian Stack Overflow, but it always displays the phrase "Finish registration". I have tried logging in by different methods — Facebook, Google, etc. — but it still says that my registration is not finished. Can someone help me with it? or explain what I should do there to finish the registration?  P.S: I can't write questions in Meta Russian Stack Overflow because it says that my registration is not finished.  P.S.S: I have already tried "Click the "register" link at the top of the page." it brings to the login page with the phrase "Finish signing up by using any of the following options:". I have already tried all options there. I also can't merge them because they already linked. Calculating MEAN and STANDARD DEVIATION confussed Quoted headings are rendered properly on preview but not when posted With markdown, you can use some dashes for headings. For example, this: Hello ---- this is some other text  renders as this: Hello this is some other text This is fine and works well. When I want to quote that text is when the problem arises, since this Markdown: &gt; Hello &gt; ---- &gt; this is some other text  When written down shows well in the preview but not when posted:  Hello this is some other text   As an example, see an screenshot of the preview:    and a screenshot of the posted content, where the ---- becomes a &lt;hr&gt;:  Note a similar bug I also reported: . Towards the end of , it's revealed that Borden accomplishes his Transported Man trick by using his twin brother, Fallon, as a double. It then becomes clear that he has been doing this in his personal life as well as on stage - each brother leads 'half a life', sometimes appearing as Borden and sometimes as Fallon. This is how he completes the illusion: one Borden goes into the first door, the other Borden emerges from the second door a moment later. Angier doesn't know how Borden does the trick, and doesn't believe Borden uses a double despite being told as much by Cutter. He follows what he believes to be a clue in Borden's notebook and travels to Colorado to meet Nikola Tesla, who Angier believes can build a machine that can help him perform the trick. Angier believes that Tesla built a similar machine for Borden. However, the final pages of the notebook reveal that Tesla was merely a red herring, designed to get Angier out of Borden's way for a long time. Tesla, it turns out, had never built such a machine before. At this point, Tesla agrees to build Angier's machine anyway. Instead of building a machine that transports matter, he builds one that duplicates it. Angier uses this machine in his act, but in order to avoid having to deal with multiple clones (the &quot;prestige materials&quot;), one of them must die as part of the act. This all makes sense, so far, but I find it hard to believe that Borden's use of the word 'Tesla' as the key to his cipher is random. It's too coincidental that he sends Angier on a wild goose chase, but Angier returns with a working machine. A film that is otherwise so tightly plotted shouldn't rely on coincidence to move the narrative forward, so there must be something else going on. Is it possible that Borden cloned himself using Tesla's machine? Given I have Drupal 9 composer installation with composer-patches plugin and given a contrib module with a stable v8 release, but no v9 release (not even dev branch) and given that contrib module has a working v9 patch in the issue queue  is there any method to install that module + patch in composer? Even if I manually add both, the package and patch, to my composer.json, I still can't require or update this module with composer due conflicting versions. I really want to avoid duplicating /contrib code into my project's /custom codebase. My current workaround is:  forking that module to my own, private git repo applying patch there creating a new composer.json in my private git, and changing the package vendor to my custom_private_vendor adding my private git as VCS repo in the D9 project's composer.json and then composer require custom_private_vendor/contrib_module  This fulfills my goal of not duplicating the contrib module in my project's custom codebase, but every time I do this I feel the urge to wash my dirty hands. Is there something more elegant like composer require drupal/contrib_module --apply-patch-first or can I somehow target drupal.org's git with a specific patch included? With slapd.conf you could globally disable anonymous binding and require authentication with the following static directives:  disallow bind_anon require authc   How can I achieve the same global settings, but using the new cn=config live configuration method? Is there a way to kill a process tree using the terminal?  By killing a process tree, I mean killing all descendants of a process along with the process it self.  I tagged this question htop because I am using that utility a lot these days and it would be cool if there was an easy way to kill a process tree inside htop (something better than just selecting all the processes in the subtree). Difference between cp -r and cp -R (copy command) Does "It snowed hard Monday" require an "on"? I came across an English learner writing     It snowed hard Monday.   After saying that it didn't snow on Friday and Saturday.  It didn't quite feel right to me.  I'd be okay with     It snowed hard.   or     It snowed Monday.   Is it okay for there to be two things ("hard" and "Monday") modifying the snowing without an "on" breaking things up a bit? halt, poweroff, shutdown, reboot don't require root? For some reason, I can run halt, poweroff, shutdown, and reboot as a regular user without root. How can I fix this? Is it something to do with user groups, or is it a seting somewhere? Take the following two lines of code:  for (int i = 0; i &lt; some_vector.size(); i++) {     //do stuff }   And this:  for (some_iterator = some_vector.begin(); some_iterator != some_vector.end();     some_iterator++) {     //do stuff }   I'm told that the second way is preferred. Why exactly is this? Why does pressing a transform hotkey not display the axes on the selected object? I open Blender 2.80 (official release, not a beta or RC) and get the new scene with the usual 3 objects present (camera, light and cube). I select the cube, press 't' for the tools menu and click on the Move tool. The usual 3 axis glyph appears at the cube's origin as expected. But if I use the hotkey 'g' to activate the move transform instead of selecting the tool from the menu with the mouse this glyph does not appear. The exact same problem exists if I use the a hotkey for rotate or scale as well. Why? Is there some clickable checkbox setting hidden somewhere that could have disabled this? These may be separate questions, but the following MWE:    \usepackage{pdfpages} ...   \addcontentsline{lot}{subsection}{\ref{tab:UserRoles} \textbf{User Roles}}   \includepdf[pages={-}, pagecommand={\label{tab:UserRoles}}, offset=0in -1in, addtolist={9, table, {The User Roles table}, tab:UserRoles}]{UserRolesTable}   ...   has several unexpected behaviors.   I get the following warning:  Package pdfpages Warning: There's something wrong with the entries of `addtolist'. Not all entries were processed. Check `addtolist' [in the MWE]."    Probably due to the \label not being bound to the inserted pdf (in a table environment), my inserted PDF is numbered using the section, and not the expected "Table X" value.   The manually-inserted LoT line (which also uses the section number rather than the incremented table number) is not formatted like the other lines in the LoT - the number lines up, but the table caption itself is not aligned with the others in the list.   The source PDF has no errors and displays correctly in the output PDF.  PDFLaTeX -> BibTex    MWE:  \documentclass[11pt,letterpaper,twoside,final]{article} \usepackage{pdfpages} \begin{document} \listoftables \begin{center} \textbf{Table \ref{tab:UserRoles} - The User Roles Table} \addcontentsline{lot}{subsection}{\ref{tab:UserRoles}  \textbf{User Roles}} % manual entry in ToC  \includepdf[pages={-}, pagecommand={\label{tab:UserRoles}}, offset=0in -1in, addtolist={9, table, {The User Roles table}, tab:UserRoles, lot}]{UserRolesTable} \end{center} \end{document}