How to run a method from other class properly?
Access NSMutableArray from another class - Objective C
For some reason, I have a server that if ssh into another server...you don't need to enter the  password.  How is this done? Can someone give me step by step instructions please? Phase shift of 180 degrees of transversal wave on reflection from denser medium Can anyone please provide an intuitive explanation of why phase shift of 180 degrees occurs in the Electric Field of a EM wave, when reflected from an optically denser medium?  I tried searching for it but everywhere the result is just used.The reason behind it is never specified. Why does the reputation need to be publicly displayed? What is the probability one card from each suit will be represented when 5 cards are dealt? Why don't I get $e$ when I solve $\lim_{n\to \infty}(1 + \frac{1}{n})^n$? What happens when a familiar from the Find Familiar spell "dies"? Colors differ in the dual monitor I use a dual monitor.  The colors appear entirely different on the new monitor than they do on my laptop.  When you are selecting colors etc, to be included in a website design, it totally freaks me out.  Is there no software solution that finds how the settings of one of the monitor is and puts that to the second one?  Otherwise what all settings do I need to change manually on the second monitor to make it appear as it does on the laptop?  Thanks in advance. Sometimes I have asked a question which got no answers, but is answered in the comments to the question.  How should I handle these questions? I can't accept an answer, so it is never an accepted question.  For example this one:   (ok here the answer in the comments is from me, but nevertheless I also have others of them) How do lexical closures work? While I was investigating a problem I had with lexical closures in Javascript code, I came along this problem in Python:  flist = []  for i in xrange(3):     def func(x): return x * i     flist.append(func)  for f in flist:     print f(2)   Note that this example mindfully avoids lambda. It prints "4 4 4", which is surprising. I'd expect "0 2 4".   This equivalent Perl code does it right:  my @flist = ();  foreach my $i (0 .. 2) {     push(@flist, sub {$i * $_[0]}); }  foreach my $f (@flist) {     print $f-&gt;(2), "\n"; }   "0 2 4" is printed.  Can you please explain the difference ?    Update:   The problem is not with i being global. This displays the same behavior:  flist = []  def outer():     for i in xrange(3):         def inner(x): return x * i         flist.append(inner)  outer() #~ print i   # commented because it causes an error  for f in flist:     print f(2)   As the commented line shows, i is unknown at that point. Still, it prints "4 4 4". System Settings icons missing in 14.04 What editors/IDEs are available for easing the process of writing TeX/LaTeX documents? Please state some useful features like code completion, spell checking, building final DVI or PDF files, etc.  This question is undergoing a systematic refurbishment, see  on Meta. If you’d like to see another editor feature covered here or to take care of an editor that’s not covered yet, share your ideas in that meta question.  List of editors Links to answers. How do I properly clean up Excel interop objects? I'm using the Excel interop in C# (ApplicationClass) and have placed the following code in my finally clause:  while (System.Runtime.InteropServices.Marshal.ReleaseComObject(excelSheet) != 0) { } excelSheet = null; GC.Collect(); GC.WaitForPendingFinalizers();   Although this kind of works, the Excel.exe process is still in the background even after I close Excel. It is only released once my application is manually closed.  What am I doing wrong, or is there an alternative to ensure interop objects are properly disposed of? Let $x_n$ be a sequence of the type described above. It is not monotonic in general, so boundedness won't help. So, it seems as if I should show it's Cauchy. A wrong way to do this would be as follows (I'm on a mobile device, so I can't type absolute values. Bear with me.) $$\left|x_{n+1} - x_n\right| \leq \frac{1}{n^2}.$$ So, we have $$ \left|x_m -x_n\right| \leq \sum_{k=n}^{m} \frac{1}{k^2}$$ which is itself Cauchy, etc., etc. But, of course, I can't just use absolute values like that. One thing I have shown is that $x_n$ is bounded. Inductively, one may show $$ \limsup_{n \to \infty} x_n \leq x_k + \sum_{k=n}^{\infty} \frac{1}{k^2},$$ although I'm not sure this helps or matters at all. Thanks in advance.  Disclaimer I've noticed that asking a large number of questions in quick succession on this site is often frowned upon, especially when little or no effort has been given by the asker. However, I am preparing for a large test in a few days and will be sifting through dozens of problems. Therefore, I may post a couple a day. I will only do so when I have made some initial, meaningful progress. Thanks. How to add a realistic flare How do I turn the little emission sphere into a realistic flaring sun. (This piece is animated with all the planets rotating and revolving) Textcase, Listings, and Tilde Consider the following MWE:  \documentclass{scrreprt}  \usepackage{textcase}  \RequirePackage{listings} \usepackage[american]{babel}  \begin{document}     \MakeTextLowercase{A~B} \end{document}   LaTeX fails with the error  ! Undefined control sequence. &lt;to be read again&gt; az                      b l.9     \MakeTextLowercase{A~B}  ?    The error seems to lie in the combination of MakeTextLowercase, the listings package and the tilde. Whenever I remove any of these three components, everything works fine. Does anyone have a clue where the problem is? Where did the world go? I was playing on my main world when my laptop ran out of power.  I found a charger and woke it up, but Minecraft had crashed.  Now, it doesn't appear in the world selection screen!  I have verified that it still exists in the Minecraft folder, and the directory contents look to be in order.  Does Minecraft save an internal flag somewhere when it crashes hard?  If so, how do I reset it? Random number generation and probability Windows 8 Setting an image on the login screen In Windows 8.1 when you log in there's the prelogin screen that has an image you can change, but then there's also the login (password entry) screen that as far as I can see is just a solid color.  How could I replace that with an actual picture? (ie, if I wanted a company logo to be displayed in the large space underneath the password entry box. Bibtex style for "Statistics and Computing" I would like to create a bibtex style which answers the requirements of Statistics and Computing journal. How could I do that? Here is an example of how the bibliography should look like:  Journal article: Hamburger, C.: Quasimonotonicity, regularity and duality for nonlinear systems of partial differential equations. Ann. Mat. Pura Appl. 169, 321–354 (1995) Book: Geddes, K.O., Czapor, S.R., Labahn, G.: Algorithms for Computer Algebra. Kluwer, Boston (1992) Book chapter: Broy, M.: Software engineering — from auxiliary to key technologies. In: Broy, M., Denert, E. (eds.) Software Pioneers, pp. 10–13. Springer, Heidelberg (2002)  In the text, the references should be as follows:  Negotiation research spans many disciplines (Hamburger 1995).  Thank you for your help! About 'start' and 'begin' Are 'begin' and 'start' interchangeable? Both &quot;This is a new start&quot; and &quot;This is a new beginning&quot; work, right? Then during games, they say &quot;Let's start&quot;, but I never heard &quot;Let's begin&quot;. So is there supposed to be a difference? And then one guy said this &quot;They could not begin to start a conversation&quot;. What is this supposed to mean? Is it correct?