i had used linux once when i was 8 back in 2001 and i used to love it as i played the games that came with the OS, then i left linux until recently since i have been hearing about all this new linux hype so i decided to give it a try.  I have used this OS since one semester now, It lives upto its hype and i am seriously in love with it and i had downloaded wine and have been playing games on it even tho all my games do not work "I'll remain patient and hope it soon becomes better"  Now the only Issue with the operating system is that the games i used to play was slower, then i went to settings and details and noticed that the laptop was using Intel instead of Nvidia GPU and optimus was not supported. I understand that there might be some devs here and experts so could any one write a tutorial for serious noobs it would help me and all the new people starting to use linux.  Also i wonder why ubuntu devs do not integrate Wine into the OS ?.  "Sorry for my english and also if i had asked a question that already had been answered as i didn't find any of them fit to work for my laptop, i bricked the OS multiple times"  P.S i also always get an error when i boot the OS and unity shows.
I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me?
When do I use the PHP constant "PHP_EOL"? When is it a good idea to use ?  I sometimes see this in code samples of PHP. Does this handle DOS/Mac/Unix endline issues? Given three matrices $A$, $B$ and $C$ such that $ABA^T C$ is a square matrix, the derivative of the trace with respect to $A$ is:  $$ \nabla_A \operatorname{trace}( ABA^{T}C )  = CAB + C^T AB^T $$  There is a proof . However, I was not able to understand the second line of the proof. it says something like this:  $$ \nabla_A \operatorname{trace}( ABA^T C )= \nabla_\bullet \operatorname{trace}(f(\bullet)A^{T}C) + \nabla_\bullet \operatorname{trace}(f(A) \bullet^T C) $$  Where  $f(A) = AB$  I tried searching the proof or any hint using google, but I couldn't fine anything. Could anyone please help me with this second line. I cannot sleep. I am obsessed with this proof. Relationship between balloon size and pressure I see numerous websites talking about how a small balloon is at higher pressure than a big balloon. This is a fun counter-intuitive factoid... unless it isn't a fact at all.  Young-Laplace gives  $$T = \Delta p \frac R2 $$  Which means that for a given tension, increasing the radius does decrease the pressure. But why would the tension be constant? A latex balloon is like a 2D spring, right? So the tension in a inflated spherical balloon should be proportional to the surface area, correct?  $$T \propto R^2 $$  But this gives  $$\Delta p \propto R$$  Which means the bigger the balloon, the higher the internal pressure. Which, again, would be the normal intuition - but it would burst the bubble of some simplified explanations. (har har) Why Did Anakin Skywalker Believe that Turning to the Dark Side of the Force Would Save Padmé? Just as the question asks: Why did Anakin come to believe that Padmé could be saved if he embraced the Dark side of the Force? Padmé clearly didn't believe it. Why was Anakin so driven to save Padmé through the dark side? User’s Guide vs Users’ Guide I’ve been looking over what has been posted regarding the use of ’s.   I used to be a Technical Writer (years ago). The title of one of our training documents was Users’ Guide.  Once, a coworker said every time he saw that title he expected users to start coming.    Never made any sense to me, but I have to admit that the majority of us didn't understand the use of s’ in place of ’s.  What is the difference? Active login not recognized on Super User Proof of property of abelian group I want to show that $\forall x$,$y\in G$, $(xy)^2=x^2y^2 \iff G $ is an abelian group.  Proof of the backward direction seems easy enough:  Assume $G$ is an abelian group. Then consider $(xy)^2=(xy)(xy)$. By associativity, $(xy)(xy)=xyxy$. Since $G$ is abelian, $xyxy=xxyy=x^2y^2$.   Proof of the forward direction I attempt by contrapositive:  That is, assume $G$ is not an abelian group. Then, consider $(xy)^2=xyxy$ as above. Yet, $xyxy\neq xxyy=x^2y^2$ since we no longer have commutativity.  Is this proof by contrapositive completely correct? Use Complete Induction of set theory to prove $\frac{1}{\sqrt{1}} + \frac{1}{\sqrt{2}} + \frac{1}{\sqrt{3}} + ... + \frac{1}{\sqrt{n}} > \sqrt{n}$. Proove by the Complete Induction for every $n\in \mathbb{N}, n \geq 1$ $$\frac{1}{\sqrt{1}} + \frac{1}{\sqrt{2}} + \frac{1}{\sqrt{3}} + ... + \frac{1}{\sqrt{n}} &gt; \sqrt{n}$$.  I know only the basis - $\frac{1}{\sqrt{1}} \geq \sqrt{1}$.  But, I dont know how to do the change from the regular induction to the induction of Set theroy(Complete Induction). Extracting only the BibTex records relevant to the paper My colleague asked me to write a page for a paper he writes. I wrote the page in LyX, compiled it to LaTeX, and sent him the TeX files. Then he reminded me that I forgot to send the .bib file with all the references.  But, my .bib file is huge - it contains over 1000 references (I have a global BiBTeX file for all my papers). The page I wrote uses only about 20 of them.  Is there an automatic way to extract from the bib file, only the records relevant to the current paper? I have been thinking about ways of teaching electronics and I'm wondering if the following is true...  For starters, when we talk about voltage as energy per unit charge, is this energy manifest simply as the kinetic energy of the electron?  So, all other things being equal, will the electrons coming out of a 4 volt battery will have twice the velocity of electrons coming out of a 1 volt battery because of ${1 \over 2}mv^2$?  This would seem to imply that the voltage drop across different parts of the circuit is essentially a comparison of the electron speeds at those points.  Furthermore doesn't this imply that the electrons are nearly halted by the time they reach the positive terminal of the battery? This makes intuitive sense to me, it seems pedagogically sound, and it provides an explanation for how electrons "know" to give up their energy across the circuit -- electrostatic repulsion communicates later resistances to earlier parts of the circuit.  How much of the above is correct? The one things that makes me suspicious is that, in this picture, electron density at the positive terminal of the battery is very high, and repulsive forces would prohibit this. On the other hand, if the Joules per Coulomb are not coming from kinetic energy, then what? The field? But wouldn't that just dissipate as light?  Something is wrong but I don't know what. Bullied boy given immense powers by an alien race who destroys the human race Looking to identify a short story I read in a sci-fi anthology as a child, about an angry, bullied somewhat misanthropic boy who is given immense near-omnipotent powers by an alien intelligence. I read this in English, sometime in the late 1990s/early 2000s. He goes on to use this power to destroy the human race, which causes him to age terribly in a very short amount of time. At the end of the story he is a lonely old man stripped of the powers he held briefly, and is alone on an isolated Earth. The aliens then proceed to invade Earth. Ignoring programming style and design, is it "safe" to call delete on a variable allocated on the stack?  For example:     int nAmount;    delete &amp;nAmount;   or  class sample { public:     sample();     ~sample() { delete &amp;nAmount;}     int nAmount; } What does kill 0 do actually? In the man page, it says:  kill [ -s signal | -p ] [ -a ] [ -- ] pid ...  pid... Specify the list of processes that kill should signal.  Each pid can be one of five things:           0      All processes in the current process group are signaled   And I tried like this in bash:  $ man kill &amp; [1] 15247 $ [1]+  Stopped                 man kill $ kill 0 $ ps 15247 pts/41   00:00:00 man   Here 0 is used as pid. As I understood, kill 0 will kill all processes in the current process, which includes pid15247. However, it didn't do anything in this example. Does anyone have ideas about how to use it? How can I run a command after boot? I would like to run the simple shell command echo 1 &gt; /proc/sys/kernel/sysrq at each boot, to enable the sysrq keys. When in boot should this be done, and where should I put a script to do it? Cycles not rendering image or movie clip used as background in the viewport How do you get \mathbb{1} to work (characteristic function of a set)? Using competitors domain with different ending to boost traffic Can you use Magic Initiate to cast a spell you already know, and still learn another spell? I have a wizard PC who wants to gain the feat Magic Initiate and use free 1st level spell to use mage armour once a day. He already knows Mage armour, so:   Can he use the Feat to gain a free casting of Mage armour once each day? Should he get another 1st level spell but not get to freely cast it once a day? Why is part of my model not being rendered? Blank question bodies in Android app Version 1.0.58  When viewing questions that contain multiple code blocks, the question is blank for a few screens. Answers and comments are OK.   I tried clearing application data, and rebooting they phone, no change. Mobile sites work perfectly.   Example:      Also, now that I posted the pictures and links, this question also went blank