Lets say I'm using atan2 to get the angle between two vectors.  atan2 gives a value in radians. I convert it to degrees using a built in function in Java. This gives me a value between 0 and 180 degrees or between 0 and -180 (the nature of atan2).  Is there a way to convert the value received with this function (after it's been converted to degrees), to the standard 360-degree-system, without changing the angle - only the way it's written? It would make it easier for me to work with.  Thanks
I know that atan2 gives me the absolute angle of any vector. But it doesn't give a value from 0 to 360 degrees. Instead, it gives a value (if I'm not mistaken), between 0 and 180, or between 0 and -180. For example, instead of giving angle 270, it will say -90.  This is a little confusing for me. Let me try to describe how I think this works, and please tell me if I'm correct. Actually, I'll draw it.    Is this correct? I'm having a little trouble understanding this. Thanks
Prove that if a number $n > 1$ is not prime, then it has a prime factor $\le \sqrt{n}$. Difference between StringBuilder and StringBuffer I'm currently developing a script for Blender to handle Mesh Frequency Decomposition.  The script is nearly complete, but i need one more thing: The SciPy library to compute eigenvalues and eigenvectors.  Following the installation instructions on , I'm able to install it as well as Numpy. Numpy works fine, but I can't even import SciPy:  Traceback (most recent call last): File "/CAF_FD.py", line 4, in &lt;module&gt; ImportError: No module named 'scipy' Error: Python script fail, look in the console for now...   By the way, I'm working on Linux 64 bit and I've installed SciPy and Numpy with my package manager.  Edit: When I try to use SciPy with a terminal prompt, it works. Why is the product of all units of a finite field equal to $-1$? Suppose $F=\{0,a_1,\dots,a_{q-1}\}$ is a finite field with $q=p^n$ elements. I'm curious, why is the product of all elements of $F^\ast$ equal to $-1$? I know that $F^\ast$ is cyclic, say generated by $a$. Then the product in question can be written as  $$ a_1\cdots a_{q-1}=1\cdot a\cdot a^2\cdots a^{q-2}=a^{(q-2)(q-1)/2}. $$ However, I'm having trouble jumping from that product to $-1$. What is the key observation to make here? Thanks! vertical alignment of text in tikz node The output from the following script \documentclass{article} \usepackage{tikz} \usepackage{graphicx} \begin{document} \begin{tikzpicture}   \node(title)[text width = 0.25\textwidth, text height = 3 cm, draw]{title};   \end{tikzpicture} \end{document}  is  How can I vertically align the text in the node? Specifying the text depth as in \node(title)[text width = 0.25\textwidth, text height = 1cm, text depth = 1 cm, draw]{     title line 1\\     title line 2\\     title line 3};  Does not result in the text being vertically centred. If I close (is delete an option ?) my Gmail account, will somebody be able to register using my email address and read my mails?  I want to close my Gmail account but I don't want anybody to impersonate me with my old address.  Same question with Yahoo! Mail. Do they allow addresses to be re-used? Why does the default Object.toString() include the hashcode? How to solve: -bash: : cannot execute binary file I have a file named b1 that contains assembly language. I am trying to execute the file on OSX using   $ ./b1   I get the following error:   -bash: ./b1: cannot execute binary file   I've looked at other similar questions, but to no avail. I'm definitely using a 64 bit architecture.   Here are output of relevant info:  $ file b1 b1: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped $ uname -a Darwin Anthonys-MacBook-Pro.local 13.0.0 Darwin Kernel Version 13.0.0: Thu Sep 19 22:22:27 PDT 2013; root:xnu-2422.1.72~6/RELEASE_X86_64 x86_64   Edit:   Ran as b1 which ended up terminating with:  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/as: fatal error in /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../libexec/as/x86_64/as Getting always extra button on display .. 1 button dont have any ID I am having problem while looping.  I am always getting an extra button. Please help.   {this.state.items.map(myitems1 =&gt; {     return (        &lt;div key={myitems1.Id}&gt;            &lt;span&gt;{myitems1.Item_x0020_Name}&lt;/span&gt;            &lt;button onClick={e =&gt; this.dosometing(myitems1.Id)}&gt;Offline&lt;/button&gt;        &lt;/div&gt;     ); })}   I can see the collection has only three (3) values, But I am getting 4 buttons on screen.   Getting always extra How are large amounts of money expected to be made during the early parts of the Waterdeep: Dragon Heist adventure? What is the best way to animate the camera path? I'm modeling a car driving along a road(speeds up, slows down, and stops at traffic lights to wait till the lights turn green, etc.) What is the best way to animate the camera path for the following scenario?   The camera starts moving from point A, and it takes 500 frames to get to point B. 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Also     I expect the account to be closed [?] 12th of May   . What preposition should be there? I think about by or due. Also if I want to ask someone a question: What date was your account closed [missing preposition?] What do I set the 'Opens with...' property to in order to get the system to run .bat files again (when they are double-clicked)?  Somehow my boss convinced his workstation that the handler for .bat files was supposed to be Word. Now, when double-clicking .bat files, they're opened up in Word. Here's the scenario...    if (entry.Properties["something"].Value != null)   attribs.something = entry.Properties["something"].Value.ToString();   While effective and working correctly, this looks ugly to me.  If I don't check for a null before performing the ToString() then it throws an exception if the property was null.  Is there a better way to handle this scenario?  Much appreciated! set of almost complex structures on $\mathbb R^4$ as two disjoint spheres The set of almost complex structures on $\mathbb R^{2n}$ is given by $$ M_n = \frac{GL(2n,\mathbb R)}{GL(n,\mathbb C)} = \mathcal C_+ \sqcup \mathcal C_-,$$ taking into account that $\det = \pm 1$ gives two disjoint sets.  How do we show that $M_2=S^2 \sqcup S^2$? Moreover, I'm a bit confused by dimensions: how does $\dim_{\mathbb R}M_2=8$ relates with the latter decomposition?  This is exercise 1.2.1 from the book Complex geometry by Huybrechts. Summation of series $\sum_{n=1}^\infty \frac{n^a}{b^n}$? How can we evaluate this series  $$\sum_{n=1}^\infty \frac{n^a}{b^n}?$$  Here $a$ and $b$ are positive integers. If $b=1$ then series will be diverging, in other cases, it will be converging, but how to find this sum?  Isn't there a simple solution which doesn't involve Stirling numbers? How can I use wget to get files recursively if the username contains an @? Firstly my main goal is to try and get FTP files recursively in Centos.  However the actual FTP login contains an @ which ruins the syntax.  Is there some way to place the username in "double quotes" or some such equivalent such that I can use @in the username? The buttons on the modal dialog box for leaving a page with unsaved changes are confusing If you are editing a question and decide to close the tab/window/whatever, SO opens up a dialog box asking you if you are sure. The buttons for this dialog are "OK" and "Cancel". However, what these map to is not entirely obvious. It would make more sense to change them to action words describing what they do. For example, it could be "Close this Question" and "Stay Here". This would eliminate the need to explain which button does what in the dialog itself and require less work from the user. Why do Kurama and Gyuki appear as chakra while other bijuu don't? In Naruto, Kurama (the Nine-tailed bijuu) appears as chakra, as does Killer B's bijuu, Gyuki.      Other bijuu, however, don't appear that way. What is different between them? Consider the smallest number in each of the $n\choose r$ subsets (of size $r$) of $S=\{1,2,\ldots,n\}$... Consider the smallest number in each of the $n\choose r$ subsets (of size $r$) of $S=\{1,2,\ldots,n\}$.Show that the arithmetic mean of the numbers so obtained is ${n+1}\over{r+1}$. I have no idea, how to solve it.It would be better if the solution has bijection. Please help!