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How to install software or upgrade from an old unsupported release?
How can I draw a tangent ending smoothly in a circle? I'm trying to draw a tanget on a circle, but I'm not happy with the result I get from the tangent option.    particularly, I'd like to have the lines ending smoothly in the circle. The problem is shown enlarged here:      Here is the code for this mininmal example  \documentclass{standalone} \usepackage{tikz} \usetikzlibrary{calc}  \begin{document}   \begin{tikzpicture}[thick]     \node[draw,circle,xshift=2.2cm] (big) [minimum size=25mm] {};     \node[draw,circle] (small) [minimum size=2mm] {};     \draw (small.south) -- (tangent cs:node=big,point={(small.south)});     \draw (small.north) -- (tangent cs:node=big,point={(small.north)},solution=2);    \end{tikzpicture} \end{document}   I'd greatly appreciate any advice allowing me to do this! No notification (+15) for accepted answer If integral is zero and function is continuous and non negative, then what about the function? Let   $$f(x) = (x-1)(x-2)(x-3)(x-4)(x-5),\quad -\infty&lt; x&lt;\infty.$$   The number of distinct roots of equation   $$\frac{d}{dx}f(x) = 0$$   is exactly ?     The only method that I know is to multiply and then find the derivative of function then apply Sturm's theorem but it seems vague when you have to solve the question in 3 to 5 minutes . So you are requested to suggest a plausible alternative approach. When is $\mathbb{F}_p[x]/(x^2-2)\simeq\mathbb{F}_p[x]/(x^2-3)$ for small primes? I saw many saying that the latest version of Ubuntu 16.04 includes an opensource driver for ATI. I have an HP laptop with AMD 6770m + Intel HD 3000 hybrid graphics and wants to install Kubuntu on it. I created a bootable USB drive of Kubuntu 16.04 and booted from it just to check everything works perfectly (I don't want to install it separately and ruin bootloader as of now). But my laptop is getting too hot and the battery is not lasting for more than 30 mins. Also the brightness control is not working at all and it stays high always.   How can I get hybrid graphics on Kubuntu/Ubuntu working well? I am ready to turn off the ATI card since I am not going to play any games on Linux. I just need the Intel graphics + Cool Laptop + Good battery Life + Brightness control.  My BIOS setting for switchable graphics mode is FIXED. Do I need to change it to DYNAMIC?  UPDATE  I wasn't able to make things work in 16.04 so installed 14.04 LTS along with the AMD Catalyst driver. Now everything works perfectly fine. Below are the steps.   Clean install Ubuntu 14.04 LTS Install the fglrx catalyst drivers using “Additional Drivers” window. This will enable us to switch graphics Restart Ubuntu FAN Noise Fix - Refer this  and install i8kutils Brightness Control - Check this     is the official documentation for AMD/Intel hybrid graphics Choosing power supply, how to get the voltage and current ratings? Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device. Very difficult integral (for me) Could someone point me to an online resource where I can look up  $$ \int_{-\infty}^\infty \int_{-\infty}^\infty \int_{-\infty}^\infty \frac{\cos(\vec k\cdot\vec x)}{\sqrt{|\vec k|^2+m^2}}\,dk_1\,dk_2\,dk_3$$  where $\vec k$ and $\vec x$ are 3-vectors, and $m$ is a constant.  Also, if you know how to do it step by step and want to show off your fancy integration, that would also be very helpful.  Thanks ;) Suppress Fancy header and footer on first page only. I'd like to do something like this to tick a checkbox using jQuery:  $(".myCheckBox").checked(true);   or  $(".myCheckBox").selected(true);   Does such a thing exist? How to center text vertically within a textbox in Photoshop Escape velocity from long ladder How to take a site offline using Drush? How to get the day, year, hours, min Individually from date format "yyyy-MM-dd'T'HH:mm:ss.SSSZ"? Using Drupal 7.14 with the PHP filter on I have the following in a Basic Page content type:  &lt;?php if ($is_mobile == TRUE):?&gt; &lt;div class="fb-like-box" data-href="http://www.facebook.com/a page" data-width="710" data-height="600" data-show-faces="false" data-border-color="#73AA4B" data-stream="true" data-header="false"&gt;&lt;/div&gt; &lt;?php else: ?&gt; &lt;div class="fb-like-box" data-href="http://www.facebook.com/a page" data-width="900" data-height="600" data-show-faces="false" data-border-color="#73AA4B" data-stream="true" data-header="false"&gt;&lt;/div&gt; &lt;?php endif; ?&gt;   I get the error message:  Notice: Undefined variable: is_mobile in eval() (line 1 of D:\websites\modules\php\php.module(80) : eval()'d code).  I sort of understand - I'm trying to grab a variable from the Drupal system but is there any way to do this? Maybe using Tokens? Multivariable Delta Epsilon Proof $\lim_{(x,y)\to(0,0)}\frac{x^3y^2}{x^4+y^4}$ --- looking for a hint Prove that $|\log(1 + x^2) - \log(1 + y^2)| \le |x-y|$ I need to show that $ \forall x,y \in \mathbb R, |\log(1 + x^2) - \log(1 + y^2)| \le |x-y|$  I tried using concavity of log function: $\log(1 + x^2) - \log(1 + y^2)=\log(\frac{1 + x^2}{1 + y^2})=\log(\frac{x^2y^2}{(1 + y^2)y^2}+\frac{1}{1 + y^2}) \ge \frac{2(\log(x)-\log(y))}{1+y^2}$  Also the middle value theorem: $0&lt;\frac{\log(1 + x^2) - \log(1 + y^2)}{x^2-y^2} &lt;1$  But both attempts has not led too far. Allow applications downloaded from anywhere in macOS Sierra In previous versions of the OS in the security pane, you are provided an option of:    But in this version there is no option anywhere:    Is there a way that I can turn on anywhere? (via Terminal maybe?) Android App sometimes loses answer drafts For the recently reported production (January 2017) of metallic hydrogen in the laboratory - what is the evidence exactly? My google news page has burst forth the news that metallic hydrogen has been produced in a laboratory using a diamond anvil cell. Only  mentions (at this particular moment) that it has been called into question at - at least - premature. That can be read about in Nature:   Here I only want to ask about the evidence. Is it only the sudden change in visual appearance change as recorded in a camera on top of the microscope, at a specific temperature and pressure? That it "looks shiny?" Or is there actually more direct data than that?  note: I am not asking if the data is sufficient or not, nor if it is convincing, or metallic or not. Just a narrowly defined question about the extent of the observations that have lead to the proposal that a metallic state was achieved.     above: potentially three states of hydrogen as viewed in a diamond anvil cell, from .