ubuntu 16.04.3 - when trying to do:   sudo apt-get update    This is what I get:  Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done The following packages have been kept back:   libegl1-mesa libgl1-mesa-dri libinput10 libmirclient9 libwayland-egl1-mesa libxatracker2   linux-headers-generic linux-headers-virtual linux-image-virtual linux-virtual 0 upgraded, 0 newly installed, 0 to remove and 10 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y Setting up mysql-server-5.7 (5.7.19-0ubuntu0.16.04.1) ... ERROR: Unable to start MySQL server: 2017-09-04T11:14:27.542500Z 0 [ERROR] unknown variable 'validate_password_check_user_name=1' 2017-09-04T11:14:27.546320Z 0 [ERROR] Aborting Please take a look at https://wiki.debian.org/Teams/MySQL/FAQ for tips on fixing common upgrade issues. Once the problem is resolved, run apt-get --fix-broken install to retry. dpkg: error processing package mysql-server-5.7 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server:  mysql-server depends on mysql-server-5.7; however:   Package mysql-server-5.7 is not configured yet.  dpkg: error processing package mysql-server (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.       Errors were encountered while processing:  mysql-server-5.7  mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1)
My overall upgrade went well, but I am left with a critically lingering issue of mysql-server not being able to install itself, and nothing I am trying gets it to work.  This is the error I see when trying to install/reinstall it:  Setting up mysql-server-5.7 (5.7.11-0ubuntu6) ... Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details. invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing package mysql-server-5.7 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server:  mysql-server depends on mysql-server-5.7; however:   Package mysql-server-5.7 is not configured yet.  dpkg: error processing package mysql-server (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.                    Processing triggers for systemd (229-4ubuntu4) ... Processing triggers for ureadahead (0.100.0-19) ... Errors were encountered while processing:  mysql-server-5.7  mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1)   I've tried completely removing it, though doing so attempts to install MariaDB because of dependencies (?). Any suggestions on what I can do to fix this would be most welcome.  EDIT: Looks like I'm not the only one:
Is the Higgs boson an elementary particle? If so, why does it decay? The  is an excitation of the Higgs field and is very massive and short lived. It also interacts with the Higgs field and thus is able to experience mass.   Why does it decay if it is supposed to be an elementary particle according to the standard model? Variance of sample mean. Let $X_1, X_2, \ldots X_n$ be random variables with mean $\mu$ and variance $\sigma^2$. We define the sample mean $\bar{X} = \sum_{i = 1}^n X_i$.  I am having trouble understanding why the variance of $\bar{X}$ is $\sigma^2 / n$.  Here is what I worked out thus far:  $$\begin{gather} \sigma_\bar{X}^2 = E((\bar{X} - \mu)^2) = E(\bar{X}^2 - 2\bar{X}\mu + \mu^2) = E(\bar{X}^2) - 2\mu E(\bar{X}) + E(\mu^2) = E(\bar{X}^2) - \mu. \end{gather}$$  However, I'm not sure what to do with the $E(\bar{X}^2)$. In Star Trek, does the original die in teleportation? I am just curious.  If I am teleported is the original me dead and the teleporter just makes another copy of me there[at destination]? Where to locate "sockets" I am new to this, so sorry if its obvious. I am running a Debian server and installing the likes of UWSGI, NGinx etc on there. The configurations keep talking about pointing to "sockets".  In the build options I seem to be able to specify where the sockets for each program go. By default it looks like most of them go in /tmp (not all of them).  Is this a good place for them to go? I'm trying to keep things as organized as possible but just bunging them in /tmp doesn't seem like the best option. I'm looking for a specific scifi book that I read years ago, I only partially remember the story, and I don't remember the author or the title.  What I remember of the story is:   An alien race picks up a signal from humans that includes instructions on how to make their own humans (genetic instructions). The humans grow up knowing they are created and are taught by the alien race. They are eventually given resources to build a ship, and go looking for their origins. They eventually find the solar system, but nobody answers. They find some stations orbiting earth and find that the station is very old, so old in fact that humans have long been extinct and other creatures have reached local space, and have been looking around the station as an archeological dig. I think they refer to two developed races from earth, but one developed from rats.   If anyone know what story this is, and can point me at it, its been driving me crazy for at least 15 years, and I think it's actually been much longer, since I can't remember when I read it. I have a user control that I load into a MainWindow at runtime. I cannot get a handle on the containing window from the UserControl.   I have tried this.Parent, but it's always null. Does anyone know how to get a handle to the containing window from a user control in WPF?  Here is how the control is loaded:  private void XMLLogViewer_MenuItem_Click(object sender, RoutedEventArgs e) {     MenuItem application = sender as MenuItem;     string parameter = application.CommandParameter as string;     string controlName = parameter;     if (uxPanel.Children.Count == 0)     {         System.Runtime.Remoting.ObjectHandle instance = Activator.CreateInstance(Assembly.GetExecutingAssembly().FullName, controlName);         UserControl control = instance.Unwrap() as UserControl;         this.LoadControl(control);     } }  private void LoadControl(UserControl control) {     if (uxPanel.Children.Count &gt; 0)     {         foreach (UIElement ctrl in uxPanel.Children)         {             if (ctrl.GetType() != control.GetType())             {                 this.SetControl(control);             }         }     }     else     {         this.SetControl(control);     } }  private void SetControl(UserControl control) {     control.Width = uxPanel.Width;     control.Height = uxPanel.Height;     uxPanel.Children.Add(control); } Can I enable the Windows 7 Start menu in Windows 10? I've upgraded from Windows 7 to Windows 10 and now I only find this new slower Start menu with all the tiles in it   (picturesource: )  Can I enable the older Windows 7 one again which suites my needs more? If $f(x + y) = f(x) + f(y)$ showing that $f(cx) = cf(x)$ holds for rational $c$ For $f:\mathbb{R}^n \to \mathbb{R}^m$, if $f(x + y) = f(x) + f(y)$ for then for rational $c$, how would you show that $f(cx) = cf(x)$ holds?  I tried that for $c = \frac{a}{b}$, $a,b \in \mathbb{Z}$ clearly  $$ f\left(\frac{a}{b}x\right) = f\left(\frac{x}{b}+\dots+\frac{x}{b}\right) = af\left(\frac{x}{b}\right) $$ but I can't seem to finish it, any help? I'm trying to identify a science fiction series on UK TV during the 70s, but I can only recall the following:   A party of adults and children. There was a woman with a telepathic bond to her cat: she could look into its eyes to see what it had seen. Time travel was involved. I think it may have been inadvertent or uncontrolled time travel. On one occasion the party encountered an Elizabethan seaman who demanded to know if Elizabeth was still queen. They party replied "err... yes" because they didn't want to have to explain time travel. So I am using  package for code examples. But there is a problem. When I copy the code examples from the final PDF document, they are usually not the same - the indentation is gone, there are random spaces after parenthesis, etc. Does anyone know how to make sure that the code that I copy from the final document is the same as I wrote it in the LaTeX document?  Here is what I mean. Compile this document:  \documentclass[12pt,oneside]{memoir}  \usepackage{listings} \usepackage[T1]{fontenc} \usepackage{xcolor} \usepackage{textcomp}  \definecolor{codebg}{HTML}{EEEEEE} \definecolor{codeframe}{HTML}{CCCCCC}  \lstset{language=Awk} \lstset{backgroundcolor=\color{codebg}} \lstset{frame=single} \lstset{framesep=10pt} \lstset{rulecolor=\color{codeframe}} \lstset{upquote=true} \lstset{basicstyle=\ttfamily} \lstset{showstringspaces=false}  \begin{document}  This code example prints out all users on your system:  \begin{lstlisting}[language=c] #include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;string.h&gt;  #define MAX_LINE_LEN 1024  int main() {     char line[MAX_LINE_LEN];     FILE *in = fopen("/etc/passwd", "r");     if (!in) exit(EXIT_FAILURE);      while (fgets(line, MAX_LINE_LEN, in) != NULL) {         char *sep = strchr(line, ':');         if (!sep) exit(EXIT_FAILURE);         *sep = '\0';         printf("%s\n", line);     }     fclose(in);     return EXIT_SUCCESS; } \end{lstlisting}  \end{document}   Now compile it, open it, select and copy the code example and paste it in a text editor. Here is the result I get:  # include &lt;stdio .h&gt; # include &lt;stdlib .h&gt; # include &lt;string .h&gt; # define MAX_LINE_LEN 1024 int main () { char line [ MAX_LINE_LEN ]; FILE *in = fopen ("/ etc / passwd ", "r"); if (! in) exit ( EXIT_FAILURE ); while ( fgets (line , MAX_LINE_LEN , in) != NULL ) { char * sep = strchr (line , ':'); if (! sep ) exit ( EXIT_FAILURE ); * sep = '\0 '; printf ("%s\n", line ); } fclose (in ); return EXIT_SUCCESS ; }   Jeez! What's this... The indentation is gone. There are spaces in included headers &lt;stdio .h&gt;, there are spaces after parenthesis [ MAX_LINE_LEN ].  Anyone knows how to fix this? I'd like the code examples in my book to be copy/paste-able into a text editor so people can try them out easily. How to setup synctex with vim, pdflatex and an open-source PDF-viewer under Linux? I would like to create a virtual device in Android Studio but I can't because hardware acceleration is disabled.  I went to the BIOS and there are two option :  AMD-SVM AMD-IOMMU   Both are enabled.  I also downloaded the HAXM installer from the SDK manager and tried to run it from the   C:\Users\%user%\AppData\Local\Android\Sdk\extras\intel\Hardware_Accelerated_Execution_Manager  with intelhaxm-android file.  I got an error telling me :   This computer does not support Intel Virtualization technology VT X or it is exclusively used by Hyper V. HAXM cannot be installed. Please ensure that hyper V is disabled in windows feature   It makes sense that I can't activate Intel Virtualization technology because I have AMD Ryzen 7 2700U.  With my previous computer it worked just fine but I had an Intel processor.  Some tutorials online suggested to enable windows Hyper-V feature but it's only available for windows 10 pro.  Does anyone know a way to activate hardware acceleration with AMD processor and without Hyper-V feature? Windows registry entries for default explorer view Why uniform closure $\mathscr{B}$ of an algebra $\mathscr{A}$ of bounded complex functions is uniformly closed? Let $\mathscr{A}$ be an algebra of bounded complex functions. (Or if necessary, continuous and domain of functions is compact)  Definition:  $\mathscr{B}$ is uniformly closed iff $f\in\mathscr{B}$ whenever $f_n\in \mathscr{B} (n=1,2,\cdot)$ and $f_n\rightarrow f$ uniformly.  $\mathscr{B}$ is the uniform closure of $\mathscr{A}$ iff $\mathscr{B}$ is the set of all functions which are limits of uniformly convergent sequences of members of $\mathscr{A}$.  ============  Let $\mathscr{B}$ be a uniform closure of $\mathscr{A}$.  How do i prove that $\mathscr{B}$ is uniformly closed in ZF?  Does Stone-Weierstrass theorem require choice since it is critical to prove Stone-Weierstrass Theorem? Trig sum: $\tan ^21^\circ+\tan ^22^\circ+\cdots+\tan^2 89^\circ = \text{?}$ As the title suggests, I'm trying to find the sum $$\tan^21^\circ+\tan^2 2^\circ+\cdots+\tan^2 89^\circ$$ I'm looking for a solution that doesn't involve complex numbers, or any other advanced branch in maths. The solution can involve techniques such as induction, telecoping, etc, but preferably only ideas from precalculus, e.g. trig identities, polynomials, etc.  EDIT: I know that the sum is a rational number. How to generate a 2D array data structure in tikz? I need to illustrate a 2D array data structure in my document. This is a picture I found on the internet. I want something similar.    I also want to show the memory layout in the illustration. Something like this:   Can someone help me with drawing them in Tikz? Thanks in advance.  MWE  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{tikz} \usetikzlibrary{matrix,backgrounds}  \begin{document} \begin{tikzpicture}[font=\ttfamily, array/.style={matrix of nodes,nodes={draw, minimum size=7mm, fill=green!30},column sep=-\pgflinewidth, row sep=0.5mm, nodes in empty cells, row 1/.style={nodes={draw=none, fill=none, minimum size=5mm}}, row 1 column 1/.style={nodes={draw}}}]  \matrix[array] (array) { 0 &amp; 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 &amp; 6 &amp; 7 &amp; 8 &amp; 9\\   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;  \\}; \node[draw, fill=gray, minimum size=4mm] at (array-2-9) (box) {};  \begin{scope}[on background layer] \fill[green!10] (array-1-1.north west) rectangle (array-1-10.south east); \end{scope}  \draw (array-1-1.north)--++(90:3mm) node [above] (first) {First index}; \draw (array-1-10.east)--++(0:3mm) node [right]{Indices}; \node [align=center, anchor=south] at (array-2-9.north west|-first.south) (8) {Element\\ (at index 8)}; \draw (8)--(box); % \end{tikzpicture} \\ \begin{tikzpicture}[font=\ttfamily, array/.style={matrix of nodes,nodes={draw, minimum size=7mm, fill=red!30},column sep=-\pgflinewidth, row sep=0.5mm, nodes in empty cells, row 1/.style={nodes={draw=none, fill=none, minimum size=5mm}}, row 1 column 1/.style={nodes={draw}}}]  \matrix[array] (array) {  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp; \\  &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;  \\}; % \end{tikzpicture} \\ \begin{tikzpicture}[font=\ttfamily, array/.style={matrix of nodes,nodes={draw, minimum size=7mm, fill=blue!30},column sep=-\pgflinewidth, row sep=0.5mm, nodes in empty cells, row 1/.style={nodes={draw=none, fill=none, minimum size=5mm}}, row 1 column 1/.style={nodes={draw}}}]  \matrix[array] (array) {  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp;  &amp; \\  &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;   &amp;  \\}; % \end{tikzpicture} \end{document} Basic If/Then in Python Parser of ArcGIS Field Calculator? How does a wheelie work? So I've been trying to create a mathematical model for an electric motorcycle and began to wonder about the maximum possible torque that could be supplied to the rear driven wheel without having the bike begin to lift up on one wheel.  I found ways to calculate this value online; however, the basic concept as to how the bike actually lifts escapes me.    My problem started when I began to think about what axis the bike will rotate about when it is doing the wheelie.  My first intuition was that the frame and front wheel, together, rotate about the rear axle.  But when I drew a free body diagram of the frame/front wheel system just at liftoff (see below) I made note that the only forces acting about the rear axle, point O, is the force of weight.  This means that an increase in applied torque and subsequently, the applied force Fa, should not effect the rotation about the rear axle.  I know that the applied force on the back wheel is indeed correlated with the propensity for a bike to wheelie, so I considered that the axis of rotation I was choosing was wrong.  If we take the free body diagram above and sum the moments about the center of mass, we would find that an increased applied force would in fact cause the solid body to rotate.  The problem with this understanding is that during rotation, the center of mass of the drawn system should actually rises relative to the surface the bike is moving across.  If the bike were to be truly rotating about its center of mass, then the back wheel would begin to dip below the surface of the road like you might see in a glitchy video game.    So I suspect that the bike is in fact rotating about the back axle, but I don't understand why, please help!  edit: I added the external torque from the back wheel to the frame, which would allow the bike to rotate about the back axle  edit 2:  I suppose that the torque acting on the frame via the engine should not effect the rotation as the movement of a motorcycle can be perfectly replicated by applying a force at the back axle.  A third possible axis of rotation might be the lowest point of the back wheel. Could someone explain the muon $g-2$ experiment problem? Where to start learning Linear Algebra? I'm starting a very long quest to learn about math, so that I can program games. I'm mostly a corporate developer, and it's somewhat boring and non exciting. When I began my career, I chose it because I wanted to create games.  I'm told that Linear Algebra is the best place to start. Where should I go?