CTRL + ALT + F1 show nothing I have installed Ubuntu 12.04 on my desktop. I have got NVIDIA 8400GS which is giving me a lot of problems. Ubuntu does not take the drivers automatically and I'm forced to work in 800 x 600. I tried to install additional drivers but it did not do anything rather it gave me an error after installation and I had to reinstall the system.  Now I'm trying to install the drivers manually, but when I go to Console mode and turning off the graphics via Ctrl+Alt+F1, the screen remains black and whatever I type, nothing happens.  How can I fix it?
Why does switching to the tty give me a blank screen? After booting to the GUI in 12.04, I attempt to move to the virtual terminal (or shell, or tty) via Ctrl-Alt-F1 (F1 through F6), and the screen remains blank. I have tried all 6 tty instances and the results are the same. Ctrl-alt-F7 brings me back to the GUI without a problem. Any thoughts?
How can I get the node id the comment is attached to in hook_comment_insert?  I tried the following code:  function mymodule_comment_insert(Drupal\Core\Entity\EntityInterface $entity) {   if ($entity-&gt;bundle() == 'comment_custom' &amp;&amp; $entity-&gt;get('entity_type')-&gt;value == 'node') {      // Below returns empty, because "$entity-&gt;get('entity_id')-&gt;value" is empty.     $node = Node::load($entity-&gt;get('entity_id')-&gt;value);      // No luck with this one too.     $node = \Drupal::routeMatch()-&gt;getParameter('node');    } } Keep items in inventory on death in Minecraft Override iTunes "media" keys (play, pause, etc) for Spotify? Simultaneously merge multiple data.frames in a list How to select distinct field values using Solr? Reading console input in MonoDevelop What is wrong with the following "proof" that $e=1$? Let's analyze this expression   $\lim_\limits{n\rightarrow\infty} (1+\frac{1}{n})^n$  It's the definition of $e$ which, as we know is not equal to $1$. So what is wrong with the following "logic":  As $\lim_\limits{n\rightarrow\infty}(a_{n}b_{n}) = \lim_\limits{n\rightarrow\infty}(a_{n})\times\lim_\limits{n\rightarrow\infty}(b_{n}) $ and $\lim_\limits{n\rightarrow\infty}(1+\frac{1}{n}) = 1$, we can say that $\lim_\limits{n\rightarrow\infty} (1+\frac{1}{n})^n=1^n$, which is equal to $1$.  I know something's wrong there, but the question is - what? Can $R \times R$ be isomorphic to $R$ as rings? Elliptical orbits of planets As we know, the velocity of the planet changes as it orbits around the sun, both in its magnitude and direction. The centripetal acceleration causes the change in the direction of velocity but I want to know what is the tangential force that acts on the planet to change the velocity by its $magnitude$. The answer normally as to why the speed changes is: If  the  force  that  the  Sun  exerts  on  the  planet increases  (as  the  planet moves closer),  then  the acceleration   of  the  planet must  increase,  resulting  in a  higher  orbital  speed,  and vice  versa. But this force is not along the body but towards the sun. So such a force should only change its direction. How to list .txt files with specific content? How do I list all .txt files with their full path that have a word 'Ubuntu' in them. Ignore non-text files. When comparing values you should ignore the case i.e. UBUNTU or ubuNtu or UbUnTu are treated as equal to the search phrase given. Being an aspiring Apple developer, I want to get the opinions of the community if it is better to learn C first before moving into Objective-C and ultimately the Cocoa Framework?  My gut says learn C, which will give me a good foundation. Why should I put a ~ before \ref or \cite? My question is in the title of this post, but extends to other referencing commands like \eqref, \citep, \citet (and the like) as well. Undefined control sequence BibTex This is one of the BibTex entries giving the problem:  @ARTICLE{2015ApJ...808L..36B,    author = {{Bonnivard}, V. and {Combet}, C. and {Maurin}, D. and {Geringer-Sameth}, A. and      {Koushiappas}, S.~M. and {Walker}, M.~G. and {Mateo}, M. and      {Olszewski}, E.~W. and {Bailey}, III, J.~I.},     title = "{Dark Matter Annihilation and Decay Profiles for the Reticulum II Dwarf Spheroidal Galaxy}",   journal = {\apjl}, archivePrefix = "arXiv",    eprint = {1504.03309},  primaryClass = "astro-ph.HE",  keywords = {dark matter, galaxies: dwarf, galaxies: individual: Reticulum II, gamma rays: galaxies, methods: statistical, stars: kinematics and dynamics},      year = 2015,     month = aug,    volume = 808,       eid = {L36},     pages = {L36},       doi = {10.1088/2041-8205/808/2/L36},    adsurl = {http://adsabs.harvard.edu/abs/2015ApJ...808L..36B},   adsnote = {Provided by the SAO/NASA Astrophysics Data System} }   and corresponding bbl file giving the error at compilation is  \bibitem{2009ApJ...697.1071A} {\sc W.~B. {Atwood}, A.~A. {Abdo}, M.~{Ackermann}, W.~{Althouse},   B.~{Anderson}, M.~{Axelsson}, L.~{Baldini}, J.~{Ballet}, D.~L. {Band},   G.~{Barbiellini}, and et~al.} \newblock {\bf {The Large Area Telescope on the Fermi Gamma-Ray Space Telescope   Mission}}. \newblock {\em \apj}, {\bf 697}:1071--1102, June 2009.   My guess is that Kile doesn't like references of the form 2015ApJ...808L..36B since these are the only ones giving the error.    Can somebody hint me to the problem in this? Thank you very much Why can’t the Doctor’s companions understand babies and horses? The Doctor claimed to speak both horse and baby. The reason human companions can understand every language is because the TARDIS translates. So why can't anyone else understand babies and horses? How to show $\lim_{n \to \infty} a_n = \frac{ [x] + [2x] + [3x] + \dotsb + [nx] }{n^2} = x/2$? This question came from the prelim exam I took last month. I have a proof that seems a bit unwieldy to me (posted as an answer), so I'm opening it up to ask if there are other ways of showing this.     Let $x$ be any positive real number, and define a sequence $\{a_n\}$ by   $$ a_n = \frac{ [x] + [2x] + [3x] + \dotsb + [nx] }{n^2} $$   where $[x]$ is the largest integer less than or equal to $x$. Prove that $\displaystyle{\lim_{n \to \infty} a_n = x/2}$. If $0$ is the zero-object $ \Longrightarrow F(0) $ is the zero object when $F$ additive When did Tom Riddle get his new face? Recently I asked about the  pertaining to Voldemorts new face. However I was corrected by ...     Well, I think the confusion comes with mixing movie canon with book canon. In Philosopher's Stone, here's what Harry sees when Quirrell unwraps his turban:           Harry would have screamed, but he couldn’t make a sound. Where there should have been a back to Quirrell’s head, there was a face, the most terrible face Harry had ever seen. It was chalk white with glaring red eyes and slits for nostrils, like a snake.          Philosopher's Stone - page 212 - UK - chapter 17, The Man With Two Faces      So it seems at some point between leaving school, and sticking his face to the back of Quirrel's head possessing Quirrel he got a new face some how.   How did he manage that? Is it some dark magic he applies? Is it from possessing snakes in Albania? How to show the inequality for $\int_{0}^{\pi/4}\tan^n(x) dx$ I can't seem to figure out the inequality option, I substituted n=2 for the answer bit is there any elegant way of getting it? Suppose that $f$ is continous on $[0,1]$ , differentiable on $(0,1)$ , and $f(0)=0$ and  $f(1)=1$.For every integer $n$ show  that there must exist $n$ distinct points $\alpha_1,\alpha_2\cdots,\alpha_n$ in that interval so that    $\sum \limits_{k=1}^n \frac{1}{f'(\alpha_k)} = n $   Is it theorem or i can show it with basic differentiation knowledge .Please give me hint . Why does $\lim_{n \to\infty}a_{n+1} = \lim_{n\to\infty}a_n$? Assume that $\{a_n\}$ is a convergent sequence. How to use the definition of a limit of a sequence to prove that $\lim\limits_{n \to\infty}a_{n+1} = \lim\limits_{n\to\infty}a_n$?