How to clear everything in Mathematica?
How do I clear all user defined symbols?
PDF of function of X I'm learning about functions of random variables and am trying to work out an example I made up. If $y = \sin(x)$ and $x$ has domain $[0, 4\pi]$, is the following the correct expression for the pdf of $y$: $$\begin{align*} f_Y(y) &amp;= \frac{d}{dy}F_Y(y)\\ &amp;= \frac{d}{dy}[F_X(2\pi) - F_X(\pi) + F_X(4\pi) - F_X(3\pi)]\\ &amp;= \frac{d}{dx}F_X(2\pi)\left|\frac{dg^{-1}(y)}{dy}\right| - \frac{d}{dx}F_X(\pi)\left|\frac{dg^{-1}(y)}{dy}\right| + \frac{d}{dx}F_X(4\pi)\left|\frac{dg^{-1}(y)}{dy}\right| - \frac{d}{dx}F_X(3\pi)\left|\frac{dg^{-1}(y)}{dy}\right|\\ &amp;=f_X(2\pi)\left|\frac{1}{\sqrt{1-0}}\right| - f_X(\pi)\left|\frac{1}{\sqrt{1-0}}\right| + f_X(4\pi)\left|\frac{1}{\sqrt{1-0}}\right| - f_X(3\pi)\left|\frac{1}{\sqrt{1-0}}\right|\\ &amp;= f_X(2\pi) - f_X(\pi) + f_X(4\pi) - f_X(3\pi)\\ \end{align*}$$ Improve alignment of "Learn more" button in "Newest badge" popup The popup when you click on your newest badge in your user profile has a &quot;Learn more&quot; button, but its alignment is suboptimal; it's too close to the top of its container:  It looks better with a 4px top margin: C++ guarantees that variables in a compilation unit (.cpp file) are initialised in order of declaration. For number of compilation units this rule works for each one separately (I mean static variables outside of classes).  But, the order of initialization of variables, is undefined across different compilation units.  Where can I see some explanations about this order for gcc and MSVC (I know that relying on that is a very bad idea - it is just to understand the problems that we may have with legacy code when moving to new GCC major and different OS)? Extra slash added to the chat room URLs in the side bar Did this character lose a limb in “The Force Awakens?” Inspired by  which states limb loss as a recurring theme, I started thinking about the final lightsaber battle. After watching The Force Awakens the second time, I was not sure if      Kylo Ren   lost a limb or just lost his lightsaber. We definitely see      Rey slash at Ren’s right hand.   So knowing that context:      Did Kylo Ren actually lose his arm/hand? Blackboard bold characters The blackboard bold font in the AMSFonts package only has capital letters.  I sometimes wish to use a blackboard bold "1", for which I can use \usepackage{bbold}. But this changes the entire blackboard bold font, and I like the original AMSFonts versions of the capital letters better.  Is there a simple way for me to get \mathbb{1} from one package and the blackboard bold capitals from another? Show that $(\mathbb{Q}^*,\cdot)$ and $(\mathbb{R}^*,\cdot)$ aren't cyclic I'm reading a book about abstract algebra, but I'm having trouble solving this excercise: "Show that $(\mathbb{Q}^*,\cdot)$ and $(\mathbb{R}^*,\cdot)$ aren't cyclic"  Where $(\mathbb{Q}^*,\cdot)$ is the group of nonzero rational numbers under multiplication and $(\mathbb{R}^*,\cdot)$ is the group of nonzero real numbers under multiplication.    Here is my attempt for the first.  Suppose $(\mathbb{Q}^*,\cdot)$ is cyclic, then $\mathbb{Q}^*=\langle\frac{p}{q}\rangle=\{(\frac{p}{q})^n,n\in\mathbb{Z}\}$, where $p$ and $q$ are coprime.  $\frac{2p}{q}$ is also in $\mathbb{Q}^*$ so it must be equal to $(\frac{p}{q})^n$ for some $n\in\mathbb{Z}$.  To solve $\frac{2p}{q}=(\frac{p}{q})^n$, I take a logarithm of both sides and end up with $1+\log_\frac{p}{q}(2)=n$, since $n$ is an integer $\log_\frac{p}{q}(2)$ must be an integer too, but it is possible only when $\frac{p}{q}=2^{\frac{1}{k}}, k\in\mathbb{N}$, (i.e. $\frac{p}{q}$ is a k-th root of $2$), but $k$ must be $1$ for $2^\frac{1}{k}$ to be rational so $\frac{p}{q}=2$ contradicting the hypothesis of $p$ and $q$ being coprime.    However I don't know whether this is a proper proof and the same reasoning cannot be applied to $\mathbb{R}^*$, I'd like you to just give me an hint towards a proof, without telling me the whole proof, if possible. How get eigenvectors without phase jump? Earlier, I voted to close  as off-topic.  The question has since been closed.  There is an , but it didn't show up in the list when I selected "off-topic".  The options were:   Meta Stack Overflow Server Fault Super User Webmasters Programmers   Questions:   Should Wordpress appear in this list? Are there any other sites that should appear in the list?   Should all non-beta sites appear in that list by default? When you click on the Opportunities tab, (assuming you haven't modified standard salesforce layout), you see a "Recent Opportunities" list. At the top of the list, there is a "New" button.     Is there a way to hide the "New" button displayed on this page? I have tried disabling the button on the "Opportunity List View" Search Layout[Setup -> App Setup -> Opportunities -> Search Layouts], but it does not remove the button from this particular view. Remove array element based on object property How to know what program is listening on a given port? I suspect a program is listening on port 8000 on my machine.  When I run the following command, I get this error:  &gt; python -m SimpleHTTPServer # Lots of python error socket.error: [Errno 98] Address already in use   If I use another port (8000 is the default), the web server runs fine.  If I run wget localhost:8000 from the command line, it returns 404 Not Found.  What can I do (or what tools are available) to find what program is listening on port 8000, and from there where that program is configured? Working on a future method to post values to external web service. But since there is a limit of 50 callouts per invocation, I am getting error "Too many future calls : 51". Cases are loaded into salesforce from external ETL in bulk. So is there a way to workaround this error.   Class  public with sharing class caseTrigger {      //method invoked by trigger after insert     public void CaseInsert(List&lt;Case&gt; caseIns){           list&lt;Id&gt; caseIds = new list&lt;id&gt;();             List&lt;Case&gt; caseList = [Select id from case WHERE Id IN :caseIds];                 for(Case c : caseList){                     if(c.Status != 'closed'){                         caseIds.add(c.id);                     }                          if(f.caseId_User.size()&gt;0){PostCases(caseIds);}      }     //postCases (future method)     @future(callout = true)     public static void PostCases(List&lt;Id&gt; Ids){         //prepare Json to post to webservice    } } If $\cot A+\cot B+\cot C=\sqrt3$ then prove that the triangle is equilateral triangle.   Trial: I can counter check that this is true as $\cot 60+\cot 60+\cot 60=3 \frac{1}{\sqrt3}=\sqrt3$.Here I also know that $A+B+C=180$. But I am unable to show it. Please help. It is my understanding that I can disable my touchscreen by adding Option "Ignore" "on" to this file                                /usr/share/X11/xorg.conf.d/10-evdev.conf   Section "InputClass"           Identifier "evdev touchscreen catchall"           MatchIsTouchscreen "on"           MatchDevicePath "/dev/input/event*"           Driver "evdev"           EndSection   so it would look like this   Section "InputClass"           Identifier "evdev touchscreen catchall"           MatchIsTouchscreen "on"           MatchDevicePath "/dev/input/event*"           Driver "evdev"           Option "Ignore" "on"           EndSection   What would happen if I simplied changed MatchIsTouchscreen to "off"?   Section "InputClass"           Identifier "evdev touchscreen catchall"           MatchIsTouchscreen "off"           MatchDevicePath "/dev/input/event*"           Driver "evdev"           EndSection   Would this disable my touchscreen? Proving that $(3n)!$ is divisible by $n! \times (n + 1)! \times (n + 2)!$ if $n$ is greater than 2 Who killed Ra's Al Ghul first, Batman or Arrow? My friend recently received a new digital drawing tablet (Wacom Intuos Pro). Among other features, there is a hole that resembles a charm hole found on mobile phones:    Other parts of the package (e.g. pen) do not have such holes, so it isn't possible to attach them using a band. What is the purpose of this hole? Is it just for attaching various charms and such? Does $G\oplus G \cong H\oplus H$ imply $G\cong H$ in general? Short Story about interminable rain on Venus