ubuntu gnome 16.04 freezes after login
Graphics issues after/while installing Ubuntu 16.04/16.10 with NVIDIA graphics
Emulate "double" using 2 "float"s Prove that for any square matrix, an invertible matrix B exists, so that BA is triangular I'm given a matrix A, its dimensions are n x n.  I am required to prove that an invertible matrix B exists, such that the product of the matrices BA is triangular.  Any help? Ubuntu 16.04 LTS Virtualbox 5.0.40 ubuntu r 115130  Today after upgrading to kernel 4.13.0-26 guest vbox machines started to crash whole ubuntu. just hard poweroff is working.  If I startup with kernel 4.10.0-42 everything works fine.  what may be the problem ? When can we use 'much' in affirmative clauses? Is there a missing definite article before caliph in 'the group's leader, XYZ, as (the) caliph'? When will my device get the Android 5.1 update (Lollipop)? Android 5.1 (Lollipop) was officially announced on March 9th, 2015.  You can review the high-level changes at the announcement on the official .  Of course, not all devices will get this update right away and others won't get it at all. Each manufacturer and carrier often choose to add their custom modifications which tend to delay the official release.  When will each device get Android 5.1, either officially or unofficially, if ever?  See also: So, if we have a large pipe which is constricted in the middle, the fluid in the middle section  will move faster. Why is it so? What dictates that liquid that an X amount of it must pass on the other side regardless of the size of the encasement?  The only reason I could think about is because that the initial pressure which causes the movement somehow is being transferred to a smaller area, but that makes no sense. Install software from packages, or build it from source? Assume $f:A\to A'$ is a function, $B\subset A'$, $C\subset A'$, and $f^{-1}(B\cap C)=\emptyset$  How can we see that $f^{-1}(B)\cap f^{-1}(C)=\emptyset$? Derivative of function with 2 variables I've leart in Calculus 1 that the derivetive of $f(x)$ is:  $$\lim_{h\to0} \frac{f(x+h) - f(x)}{h}$$.  suppose $f(x,y)$ is a function with 2 variables,  does $$f'(x,y) = \lim_{h\to0} \frac{f(x+h, y+h) - f(x,y)}{h}$$ ?  If not , what is the derivetive of function with 2 variables? "Show desktop" keyboard shortcut in Mac OS X I am using a MacBook Pro with Mac OS X 10.5. Is there a similar function to "show desktop" (shortcut is WIN+D) on a Mac?   It should hide all applications and show a clean desktop. What is the "correct" way of embedding text into math mode? Lets say I have something like:   \[ Let x = number of cats \]   (This is a contrived example, but pretend we are actually inside a long align environment block...) "Let" and "number of cats" need to be written like normal text, while x= needs to be math type text.  I've seen this:  \[ \mbox{Let } x = \mbox{ number of cats} \]   and this:  \[ \textrm{Let } x = \textrm{ number of cats} \]   They seem to produce equivalent output, but I'm not sure which is the "correct" one. Also, they are not ideal in that the extra space needs to be placed inside the text mode block, otherwise it is ignored as math mode and butts the text right up against the math.  Ideally there would be some command which allowed embedding text into an equation, which correctly inserted leading and trailing space around the block as required without adding space inside the text block.  How does one do that "correctly"? What is a word/phrase for using a term for a popular special case instead of a generic term? Can a quasiclassical electron wave packet in elliptic orbit be formed from bound hydrogen-like eigenstates? Position probability densities of eigenstates of hydrogen-like systems have axial symmetry, so that the wavefunction too much resembles the circular orbits in Bohr's model. I'd like to have a demonstration of correspondence principle, where an electron would be localized to look somewhat like a classical particle, and move in an elliptic (non-circular) orbit around a nucleus.  It seems though that if we try to make a wave packet too localized, then it'll disintegrate (get scattered by the nucleus) too fast to see anything resembling an elliptic orbit. OTOH, if we take it too spread out, it'll have to be quite far from the nucleus so as to avoid hitting it, and thus it'll have high total energy, which may appear to be above ionization threshold (at least partially), after which it'd be quite hard to analytically calculate evolution of the wave packet.  Thus my question is: is it possible to form a more or less localized wave packet, which would (on average) move in an obviously-elliptic orbit (major/minor axes ratio of 4:3 or higher), and only require bound states to fully represent it? If yes, then what properties (FWHM, apocenter, angular momentum etc.) should it have for this to be possible? How do I undo the most recent local commits in Git? How can I accept the Microsoft EULA agreement for ttf-mscorefonts-installer? I was browsing through the apt folder to try my proxy settings and I was unable to find the apt.conf file in Ubuntu 11.04. Is there any alternative file for it?  Adding proxy settings to 99-synaptic in apt.conf.d does not help as it gets overwritten everytime I restart the system. When wouldn't I use LASSO for model selection? I just installed Ubuntu 16.10 on my desktop and have a USB deathadder. The problem is I can't see where the cursor actually is because it appears only in the top left of my screen. The mouse still moves but the cursor graphic doesn't follow I am trying to define an rgb color. More specifically I want to create this color    which in rgb mode it's (98,190,177).  I tried to define this color using the following code  \documentclass{standalone}  \usepackage{tikz}  \begin{document}  \definecolor{tank}{rgb}{0.098,0.190,0.177}  %\definecolor{tank}{rgb}{98,190,177}  \begin{tikzpicture}   \coordinate (tank) at (0,0);   \draw[red, fill=tank] (-2,0.5)--(-0.5,1)--(0.5,1)--(2,0.5)--(2,-0.5)--(0.5,-1)--(-0.5,-1)--(-2,-0.5)--cycle;  \end{tikzpicture} \end{document}   but the output is totally different from what I am trying to achieve    I also tried to use \definecolor{tank}{rgb}{98,190,177} but I get no color at all. How to properly define an rgb color?