Find the least positive $x$ such that the expression $a + bx$ is divisible by $n$, where $a$, $b$, $n$ are assigned
Solving linear congruences by hand: modular fractions and inverses
Will ArcGIS for Desktop run on Windows 10? Will ArcGIS 10 run on the new windows 10 technical preview?  I am setting up an interface on my Mac and there is the free option of downloading the Windows 10 technical preview, some sort of beta version, I'm assuming.   Just wanted to see if 10.1 will run ok on Windows 10 (ignoring the Mac aspect), as this is all I am using my windows interface for? With a macro such as:  \def\naive{na\"{\i}ve}   I find that the space which I would hope to follow it, is absent. So, with  the \naive approach   I get     the naïveapproach   in the output. How do I bring back the space? What does it mean to "align" partitions? I am familiar with what partitions are, but I saw , and realised I didn't know what "aligned partitions" are.  So what does it mean to "align" partitions? What are the benefits, and the downsides? What is the type of string literals in C and C++? What are imaginary numbers? At school, I really struggled to understand the concept of imaginary numbers.  My teacher told us that an imaginary number is a number that has something to do with the square root of $-1$.  When I tried to calculate the square root of $-1$ on my calculator, it gave me an error.  To this day I still do not understand imaginary numbers.  It makes no sense to me at all.  Is there someone here who totally gets it and can explain it?  Why is the concept even useful? Is there a way to format a UTC time into any arbitrary string format I want in java?  Basically I was thinking of having some class take the timestamp and I pass it is string telling it how I want it formated, and it returns the formatted string for me.  Is there a way to do this? How to disable a USB port in Windows (XP) and make it available only for charging? Is it possible to install Office 365 (2013) on Ubuntu 15.04 Vivid Vervet? I would like to install Office 2015/365 on Ubuntu 15.04. I tried to install Office using Wine, but that did not work. Please note that I do not want virtualisation unless it has a -like behaviour, where application windows are treated like regular Ubuntu application windows by the system. I am wondering if I can minimize a multi-variable function one variable at a time. In other words, is it true that:  $min_{x_1,x_2} f(x_1,x_2)=min_{x_1} min_{x_2} f(x_1,x_2)$ Why should the minimal class be avoided? How do I show apt-get package management history via command line? Double booked - User bookmarking question recorded twice In this  one user is shown as having bookmarked  twice:  This doesn't appear to be the same question as:  or  though it's certainly possible that the cause is the same. Add self-answer delay for all users TL;DR:  I believe there are still some issues with self-answers, particularly near-immediate self-answers, which are not addressed by the current system.  This could be remedied by imposing an automated restriction on how soon self-answers will be displayed in the thread.  Allow users to submit self-answers at any time, but do not display them until certain reasonable conditions (a relatively short timeout, or the posting of a competing answer) are met.    History  This thread covers a good deal of the concerns surrounding self-answers, and some mechanisms in place to prevent "bad" self-answers from new users and other abuse of the self-answer system.    As I understand it, the following restrictions apply:   Users with &lt;100 rep cannot self-answer within 8 hours of posting a question. Self-answers cannot be accepted within 48 hours of posting. Self-answers do not provide rep from being accepted. Accepted self-answers are not pinned to the top of the thread.   Problem  This does a good job of preventing users from posting answers which should probably be comments (or not posted at all), allows superior answers to rise above accepted self-answers, and prevents some other abuses of the system.  However, there is a less tangible element of self-answers which this does not address:    Self answers are a disincentive to other users who may otherwise be willing to post more accurate, detailed material stemming from broader or deeper knowledge and/or experience than the asker has.  When someone posts an answer to their own question, it presumably means that the problem which spawned the question is solved to their satisfaction.  This is fine for the purposes of sharing information with the community, but it deters others from providing solutions to the question which may be more complete or accurate since there is not so much likelihood that the self-answerer will accept a competing answer.  Worse, in the case of near-immediate self-answers, this can remove the incentive for other users to gain reputation via up-votes because the asker has an unfair head-start.  Unless everyone is required to view new answers to questions where they have already voted on an answer, most people probably vote on a good answer and never look at the question again.  This can put (potentially) better answers at a disadvantage even when the head-start is within an hour.  Suggested Solution  Add a delay to the posting of self-answers.  The delay should be the least of these:   Until a competing answer has been posted. A reasonable amount of time to allow competing answerers a chance to post, without preventing self-answers outright.  (Suggestion: 2 hours)   To better facilitate this, and avoid completely turning people off from appropriate self-answering, I suggest the delay be handled through automation more than user limitation.  That is, the user should be allowed to submit the self-answer at any time.  But the answer will not actually be displayed to other users until one of the above conditions have been met.  This could also be applied to the existing 8-hour delay for low-rep users.  Example:  T:0 - A user finishes resolving a tough problem, just before he would have gone to SE for assistance, and decides to share his new-found knowledge with the community.  He posts a question describing his problem.  T:5 minutes - The user then posts a self-answer.  There has not yet been another answer posted to the thread.  The user is given a notice describing the restrictions in place regarding self-answers, and the answer is submitted into the database but not displayed to other users.  (Similar to how suggested edits are only displayed to the user suggesting them, until they are approved.)  T:1 hour, 15 minutes - Another user sees the unanswered question, and posts their answer.  Their answer is displayed immediately, and the self-answer is now also displayed.  T:2 hours - Had the second answer not been posted, the self-answer would automatically be displayed after this point. No sound in Ubuntu except at log in I installed Ubuntu 12.04 a month ago and am using it till now. I failed to notice that all this time there was no sound at all while running Ubuntu, even while playing a game in Wine. The weird thing is that only the startup sound comes when I log in (Indian/African drum tone), then comes the utter silence.  I tested both Digital Output (S/PDIF) and the speakers in the sound settings but can hear nothing.  Any help? Well structured URLs vs. URLs optimized for SEO Let $L$ and $R$ be $n \times n$ matrices. I am trying to solve the following minimization problem  $$ L^{k+1} := \arg \min_{L} \lambda \|L\|_{\ast} + \frac{1}{2\mu}\|L-R^{k}\|_{F}^{2} $$ $$ \mbox{s.t.}\ L \succeq 0 $$  where $\|\cdot\|_{\ast}$ and $\|\cdot\|_{F}$ denote the nuclear and Frobenius norms, respectively. Also, $k$ expresses the $k$th iteration when solving an optimization problem successively.  I don't know how to solve this problem. Would you tell me the way? Is it safe to put a clothes washer outdoors? Is dimensionality reduction almost always useful for classification? What does the word "it" mean? Even if determinism isn't true for everything that happens—even if   some things just happen without being determined by causes that were   there in advance—it would still be very significant if everything we   did were determined before we did it. However free you might feel when   choosing      [Thomas Nagel - What does it all mean? p.52]   What does the word "it" mean? I'm struggling to understand the difference between the standard error and the standard deviation. How are they different and why do you need to measure the standard error?