Solve $AX^2 + BX + C = 0$
Is there a unique solution for this quadratic matrix equation?
Why does a monopole not radiate energy in electodynamics? How to make a sound once a process is complete? I have started a long process through a terminal. Is it possible to make the Ubuntu terminal make a sound once the process is complete? This way, I don’t need to keep checking, but will instead be notified through a sound. Is it possible to assign a base class object to a derived class reference with an explicit typecast in C#?.  I have tried it and it creates a run-time error. Why do two bodies of different masses fall at the same rate (in the absence of air resistance)? I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time.  According to Galileo, two bodies of different masses, dropped from the same height, will touch the floor at the same time in the absence of air resistance.  BUT Newton's second law states that $a = F/m$, with $a$ the acceleration of a particle, $m$ its mass and $F$ the sum of forces applied to it.  I understand that acceleration represents a variation of velocity and velocity represents a variation of position. I don't comprehend why the mass, which is seemingly affecting the acceleration, does not affect the "time of impact".  Can someone explain this to me? I feel pretty dumb right now :) jsp:useBean scope Combine rows / concatenate rows I have messed up my sudoers file and I want to change the permission on it.   When I login in recovery mode, I cannot run the command chmod as it is read-only option.  I tried mount -o remount,rw / in recovery mode. Didn't work for me:  Err : Ext4-fs remount. Opts errors=remount-ro    How can I boot into recovery mode and with read-write option? Why isn't temperature frame dependent? In (non-relativistic) classical physics, if the temperature of an object is proportional to the average kinetic energy ${1 \over 2} m\overline {v^{2}}$of its particles (or molecules), then shouldn't that temperature depend on the frame of reference - since $\overline {v^{2}}$ will be different in different frames?  (I.e. In the lab frame  $K_l = {1 \over 2} m\overline {v^{2}} $, but in a frame moving with velocity $u$ relative to the lab frame, $K_u =  {1 \over 2} m \overline {(v+u)^{2}}$). How can I change the font of the top bar without changing the shell theme? I am using Ubuntu GNOME 17.04. I want to change the font of the GNOME top bar from the default font by Adapta to Fira Sans. I already have all the fonts, I just want to change the font of the top bar so it doesn't look out of place compared to everything else. Are there rules for falling in water vs. diving vs. just jumping in for various depths of water? Just realized that in DMing 5e I have unconsciously used a falling-in-water rule-of-thumb that I inherited from somewhere (maybe 2e or AD&amp;D or maybe even Pathfinder). The ruling I've been using is as follows:   No damage for 20 feet of falling. Half-damage next 20 feet. Normal damage beyond that.   Realizing there should be a Strength (Athletics) for "swimming" (in context, "diving") to take even less damage with a proper dive in sufficiently deep water, I started to look for specifics on that. Am I just missing it somewhere? (Also didn't find it searching this stack.)  Are there clear 5e rules for both jumping and diving in water of various depths? My C# application is returning 0xE0434352 to Windows Task Scheduler but it is not crashing What lens characteristics are important in star photography? When should titles like "captain" or "admiral" be capitalized? Please excuse the contrived example below, but I am wondering if this example is properly capitalised? I'm assuming that capitals are used when addressing someone directly, but lower case is used elsewhere. Can someone give some rules on this?      The captain walked into the room.    "Hi, Captain," said the admiral.   "Hi, Sir," replied the captain.   "Call me Admiral."   "Hi Admiral."   The captain and admiral stepped forward.   "Prime Minister, this is Captain Jones," said Admiral Brown.   "Pleased to meet you," said the prime minister. Why can't I install Ubuntu or Wubi on a Windows Dynamic Disk? I've been trying to install 12.04 for a while now, I'm running on Windows 7 and I already made the partition (it's dynamic). I've tried booting from a disc and also the Windows installer. I haven't tried used any repair-boot programs or anything. Every time I tried to load from either, I get an error:  command=C:\windows\sysnative\bcdedit.exe /set {03f9077f-661f-11e1-845a-d08b36406c3d} device partition=U;  retval=1  stderr=An error has occured setting the element data. 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In the sentence below, the bracketed sic would obviously denote that the punctuation preceding it was an error &mdash; that is, a semicolon should supplant the comma. Has anybody ever seen this usage, and would you support it?     The sun is high, [sic] put on some sunblock. Is GNOME Terminal a type of non-login shell? How to allow page break inside a float environment? I'm using new float enviroment to show some examples in my document. This  enviroment contains tcolorbox which provides a gray background. The main text in the enviroment is a mixture of plain text and code blocks (in lstlisting env). Each float should have it's own caption and label.  In style file:  \usepackage{newfloat} \DeclareFloatingEnvironment[name={Example}]{suppfigure}   In the main document:  \begin{suppfigure}[!h] \caption{Some code example}\label{suppfigure1} \begin{tcolorbox}[arc=0mm, left=1pt, right = 1pt, boxrule=0mm,colback = {shadow-gray}]   Text  \begin{lstlisting}  int i = 0;  \end{lstlisting}  Some more text  \begin{lstlisting}  String.Format("{0,10:0.0}", -123.4567);   \end{lstlisting}  \end{tcolorbox}  \end{suppfigure}   How can I allow page break inside the suppfigure to extend my example to multiple pages?