We’ve got plenty of time. We don’t need to/needn’t hurry Do "don’t need to" and "needn’t" mean the same or not? This is a question from an English test:     We’ve got plenty of time. We ... hurry.         don’t need to   needn’t      What's the right answer?
"He needn't say" / "He doesn't need to say" When I studied English at school (in Italy, more than 35 years ago), we were taught a rule according to which one should say, e. g., "He needn't (need not) say", but NOT "He doesn't need to say".  If I'm not mistaken, it was explained to us that the rule holds good with the following limitations:  1) only in the negative form: thus, "He needn't say", but "He needs to say", and "Does he need to say?";  2) only in the present tense: thus, "He needn't say", but "He didn't (won't, wouldn't, etc.) need to say";  3) only when an infinitive follows: thus, "He needn't see a doctor", but "He doesn't need a doctor".  But, if I google "doesn't need to", I find 125,000,000 occurrences.  I was wondering: does the rule hold good more for British than for American English?  Also, perhaps it isn't an absolute rule, and both constructions ("He needn't say" and "He doesn't need to say") are possible.  Is the rule at least a good description of the circumstances when we CAN (but needn't necessarily) use this construction?  Thank you very much, for this and the other answers.
Should "move-to-chat" be provided on demand (as a button perhaps)? When comments get too chatty the move-to-chat feature asks if you'd like to move it out. But this often happens after the fact and thus doesn't prevent it.   I propose that:   Move-to-chat be provided as a button along side so that a user who knows their question or conversation may become drawn out may elect to preempt and take the conversation "off-line" Can the category of chain complexes be realized as a functor category? As the title says, is there some sort of category $\mathsf{C}$ which can be thought of as the "walking chain complex", so that the category of chain complexes in some other category $\mathsf{A}$ can be realized as $\mathsf{A}^\mathsf{C}$ (or perhaps some subcategory thereof)? How to print original variable's name in Python after it was returned from a function? I have enum and use the variables like myEnum.SomeNameA, myEnum.SomeNameB, etc.  When I return one of these variables from a function, can I print their names (such as myEnum.SomeNameA) instead of the value they returned? Why is pruning not needed for random forest trees? Breiman says that the trees are grown with out pruning. Why? I mean to say that there must be a solid reason why the trees in random forest are not pruned. On the other hand it is considered very important to prune a single decision tree to avoid over fitting. Is there some literature available to read for this reason? Of course the trees may not be correlated but there still will be a possibility of over fitting. I heard using 'could' is for politeness. When I request something, should I say "Can you please" or "Could you please"? Does the latter sound over-polite and pretentious? Using subcaption package but subfigures end up stacked rather than side by side I'm trying to put two jpegs side by side using the subcaption package, but the images are consistently stacking on top of each other rather than side by side. All the solutions I've found simply state that the pictures have to be small enough to actually be side by side but I've tried making them smaller, too small even and they stay stacked. My code looks like this:  \begin{figure}[H] \centering \begin{subfigure}{0.5\textwidth} \centering     \includegraphics[width=0.3\linewidth]{inclusion.jpg}     \caption{inclusions}     \label{fig:inclu} \end{subfigure}  \begin{subfigure}{0.5\textwidth} \centering     \includegraphics[width=0.3\linewidth]{deform}     \caption{grain deformation}     \label{fig:deform} \end{subfigure} \caption{filler text} \label{fig:manmade} \end{figure}   Help would be greatly appreciated. Quick directory navigation in the bash shell How do I check the Database type in a Rails Migration? Prove that 1/2 + 1/4 + 1/8 ....... = 1 I've often heard that instead of adding up to a little less than one, 1/2 + 1/4 + 1/8... = 1. Is there any way to prove this using equations without using Sigma, or is it just an accepted fact? I need it without Sigma so I can explain it to my little sister.  It is not a duplicate because this one does not use Sigma, and the one marked as duplicate does. I want it to use variables and equations. An idempotent operator is compact if and only if it is of finite rank I am not a native English speaker, I usually hear “something caught my eye” but never “something caught (both) my eyes”. This seems pretty strange to me.  Cambridge Dictionaries Online provide these examples but without any explanation        (i) to get someone's ​attention:   A ​sudden ​movement ​caught my ​eye.        (ii) to get someone's ​attention, ​especially by ​looking at them:   I ​tried to catch the waiter's ​eye, so we could ​order.        (iii) to be ​attractive or different enough to be ​noticed by someone:   It was the ​unusual ​colour of his ​jacket that ​caught my ​eye.   Why is only one eye ‘caught”? Doesn't something catch our sight? We normally see with both eyes, not with one. Why can we flag/vote a question on Meta as duplicate of another question which has no accepted/upvoted answers? When we flag/vote-to-close a question as a duplicate on Stack Overflow, and that potential duplicate doesn't have any upvoted or accepted answers, we are alerted that we can't use that question as a duplicate and can't continue. This same check does however not seem to apply to Meta questions. Why not? How to delete file(s) in secure manner? Is there a way to make sure that a deleted file can not be recovered?   As you know, deleting a file by pressing shift-del or using trash doesn't mean that file is gone forever. It resides somewhere in the computer.  In day to day life, law enforcement or thieves use recovery programs to reveal our private data or something else.   They can recover all data that resides on hard disk, in RAM, and even USB.  To protect us from these people, what should one do? Which program should one use?  Note: I don't want an answer like first use a recovery program then erase that file with shred. With just one program, I want to erase all unused/deleted files on my computer. "pros and cons", "black and white", "ups and downs". Always in a fixed sequence, is there a word or phrase for these? Is there a word or phrase for two nouns or adjectives joined by a conjunction (usually "and") in a fixed sequence?        alive and well           fast and furious   hat and gloves   pen and pencil   law and order   wit and wisdom   salt and pepper   bacon and eggs   horse and carriage   Adam and Eve   ladies and gentlemen   loud and clear   heads or tails   yes or no   dead or alive Errors and Residuals I have this input:  sdkxyosl 1 safkls 2 asdf--asdfasxy_asd 5 dkd8k  jasd 29 sdi44sw 43 asasd afsdfs 10 rklyasd 4   I need this output:  sdi44sw 43 dkd8k  jasd 29 asasd afsdfs 10 asdf--asdfasxy_asd 5 rklyasd 4 safkls 2 sdkxyosl 1   So i need to sort the lines by the last column.  I don't know how many columns are in one line.  I just can't figure it out, how to do it. I don't have "perl powers". I just have ~average scripting powers with sed, awk, cut, etc..   Does somebody know how to do it? $f$ a real, continuous function, is it measurable? Let $f: \mathbb{R} \to \mathbb{R} $ be a continuous function. I need to show that is a measurable function.   I tried working with the definition:  Let $f: X \to \mathbb{R}$ be a function. If $f^{-1}(O)$ is a measurable set for every open subset $O$ of $\mathbb{R}$, then $f$ is called a measurable function.  Since $f^{-1}(O)$ also lies in $\mathbb{R}$, I think it is sufficient to show that every subset of $\mathbb{R}$ is measurable. But is this possible?   So far I concluded that $\mathbb{R}$ itself is measurable, since $$\mu(A) = \mu(A \cap \mathbb{R}) + \mu(A \cap \mathbb{R}^c) = \mu(A) + \mu(\emptyset) = \mu(A).$$ How do I need to approach? How to make clickable links and cross-references in pdfs produced by LaTeX? How can I make things link url references, my index, table of contents, and cross references clickable links in documents produced by LaTeX? I generally use pdflatex to produce my documents. ASP.NET MVC 3 localization with DisplayAttribute and custom resource provider Evaluate $\lim\limits_{n\to\infty}\frac{\sum_{k=1}^n k^m}{n^{m+1}}$ By considering:  $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^1}{n^{2}} = \frac 1 2$$ $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^2}{n^{3}} = \frac 1 3$$ $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^3}{n^{4}} = \frac 1 4$$  Determine if this is true: $$\lim_{n\to\infty}\frac{\sum_{k=1}^n k^m}{n^{m+1}} = \frac 1 {{m+1}}$$  If it is, prove it.  If it is not, evaluate $\lim\limits_{n\to\infty}\frac{\sum_{k=1}^n k^m}{{m+1}}$.