Where can I purchase video codecs for Ubuntu rather than downloading video codecs from an unknown source? I would like to purchase it.
I'm new to Ubuntu. I tried installing it with Windows 8.1, but failed I lost all my files.  I have successfully formatted my PC and installed Ubuntu, but how do I install codecs to play audio and videos files ?
In Ex Machina, can this character survive? Currently, Stack Exchange’s Markdown parser only allows four-space indents to represent code blocks:      // some code     // another line of code    and other Markdown implementations allow for an alternative syntax, that doesn’t require indenting each code line:  ``` // some code // another line of code ```   This is much more convenient to type out. It would be super useful if Stack Exchange could support this syntax.    By extension, this syntax also allow you to specify the source language right after the opening ```:  ```js // some code // another line of code ```   …which would then enable syntax highlighting for that specific language. Although it’s interesting metadata, I don’t think this feature is needed on Stack Overflow, as the syntax highlighting library works pretty well for various languages.  So, even if you would allow this syntax but ignore the ```language, this would greatly improve my productivity on Stack Exchange.  What do you think?  The moderators are currently collecting feedback regarding this feature, so please post a comment with your thoughts. Good idea? Bad idea? Don’t really care? What do you think are the benefits/drawbacks? Experiences? Let them know! Thanks! We have previously determined that  or  can attune to magic items, but one of those is a sapient creature, and the other "always obeys your commands".  A paladin's steed (per the Find Steed spell) is also 'unusually intelligent' and falls within the score range for sapient creatures.  But what about a regular old animal? If my ranger has a wolf companion, can he make that wolf attune to, say, an Amulet of Health? According to the Beast Master archetype, a companion animal "obeys your commands as best it can".  Is spending an hour 'focused only on the item' (as required for attunement) something a beast can manage?  Or what if it's not an Animal Companion, but just a riding horse, a pet dog, a trained magpie?  I know, probably this is going to be down to the DM to determine, but is there any guidance we can use to help decide whether my cat can attune to an item, and whether rubbing it with catnip would help? Here's the context       "Her heart leaping into her throat, she tiptoed into the salon. Such was her astonishment at seeing Mike chatting with her boss that she leaned against the wall, incapable of making another move."   Is this a phrase or what? Could it be used in other forms as well? Let $T(n,x)$ be the nth Chebyshev polynomial of the first kind and let $U(n-1,x)$ the $(n-1)$th Chebyshev polynomial of the second kind. Would any one kindly help show that   1) $n$ is prime iff $T(n,x)$ is irreducible in $\mathbb{Z}[x]$.  2) $n$ is prime iff $U(n-1,x)$, expressed in powers of $(x^2-1)$, is irreducible in $\mathbb{Z}[x]$.   Many Thanks!!    No "ordering" is implied here. The wording of the question was done in similar fashion  as any question in any math/research question. I do not see how a person who is asking for help would be ordering people to help.   Any way back to the topic,  For the first part of the question, I noticed that if n is prime, then T(n,x) satisfies  Eisenstein's Irreducibility Criterion. But I am not sure how to show if T(n,x) is irreducible then n is prime. It would seem that far-away stars are at such a distance that I should be able to take a step to the side and not have the star's photons hit my eye. How do stars release so many photons to fill in such great angular distances? Virtualbox Windows 10 Guest installation is freezing up in 14.04 I've installed VirtualBox using the Software Centre and I'm running a system on Ubuntu 14.04 with 8gb RAM, 64-bit dual core processor.  I want to run Windows 10, I've tried both 64 and 32 bit versions, in virtualbox. However, every time I start up windows 10 it gets to the point where the dots go round in a circle, then it freezes up and crashes back to the virtualbox manager. The only information it gives me is that the virtual machine was aborted.  I've changed the settings around a lot and nothing is working.  Any help would be appreciated.  Oh, and I've run Windows 10 technical preview on this machine before, a while ago  Thanks for any help in advance. How can you find and replace text in a file using the Windows command-line environment? I am writing a batch file script using Windows command-line environment and want to change each occurrence of some text in a file (ex. "FOO") with another (ex. "BAR"). What is the simplest way to do that? Any built in functions? When I am using Tor, and not using the Tor bundle there is a possibility of DNS leaks in certain situations.   What can be done to minimize it? Is it possible to resolve DNS via Tor? How to resolve conflicting distributions in apt-get When doing an apt-get update/upgrade I see that warning  W: Conflicting distribution: https://downloads.plex.tv/repo/deb public InRelease (expected public but got )   I was upgrading to Ubuntu Zesty 17.04 before and do not know how to fix the above. Already have seen ? but there are no suggested fixes for that.  Maybe one of you can give some hints? Thanks! How to apply CSS to iframe? Is it possible to restore a MySql database only using files from Data directory? I have a mysql installed inside a windows virtual machine. The hard drive was crashed and the system is not able to restore all again. But I can have access to entire c: ROOT. So I went to  c:/ProgramData/Mysql/Mysql Server 5.5/data/myDatabaseName    There I can see different files like: .frm, .opt, .trg and .trn. In a regular way, I could run a mysqldump to backup and restore all database from command line, but the system is not able to be restored. So I had to copy all these files and past inside inside the same  directory inside same database in another physical instance.   The issue is some tables are not been recognized by this new instance. So I think copy and past is not enough to restore the database.   What am I missing?    Note: Database has innoDb and Myisam tables. Types in MySQL: BigInt(20) vs Int(20) Bound for the correlation of three random variables There are three random variables, $x,y,z$. The three correlations between the three variables are the same. That is,  $$\rho=\textrm{cor}(x,y)=\textrm{cor}(x,z)=\textrm{cor}(y,z)$$  What is the tightest bound you can give for $\rho$? I can't seem to find an answer to this simple question, which I need for some compliance documentation.    On a default install of CentOS 6.5 (OpenSSH 5.3p1-94.el6), after how long of being idle will a user's SSH session be terminated?  I believe the following can be set to increase the idle timeout, but they are commented out by default.  $ grep -i alive /etc/ssh/sshd_config #TCPKeepAlive yes #ClientAliveInterval 0 #ClientAliveCountMax 3   Also, is there a command to dump a list of the current sshd settings?  I don't see anything in man sshd. Why does an overridden function in the derived class hide other overloads of the base class? How do you prove that these four definitions of the operator norm are equivalent? $$\begin{align*} \lVert A\rVert_{\mathrm{op}} &amp;= \inf\{ c\;\colon\; \lVert Av\rVert\leq c\lVert v\rVert \text{ for all }v\in V\}\\ &amp;=\sup\{ \lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert\leq 1\}\\ &amp;=\sup\{\lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert = 1 \}\\ &amp;=\sup\left\{ \frac{\lVert Av\rVert}{\lVert v\rVert}\;\colon\; v\in V\text{ with }v\neq 0\right\}. \end{align*}$$ Ubuntu 20.04 Font and UI elements too big on login I'm running Ubuntu 20.04 on an ASUS X99-E-10G WS w/ an NVIDIA 1080Ti and an LG 4k 32&quot; monitor which persistently gets recognized as 27&quot;. When I log in, the text of certain UI elements is ~2x the normal size. After I go to settings/universal access and turn large text on and then off again, everything is the normal size I expect. Screenshot after logging in  After turning &quot;large text&quot; on  After turning &quot;large text&quot; off  How do I get the conditions I have after cycling the &quot;large text&quot; feature to be present immediately after booting? I have the 440 version of NVIDIA's drivers installed. This is a question from Stromberg related to Steinhaus' Theorem:     If $A$ is a set of positive Lebesgue measure, show that $A + A$ contains an interval.   I can't quite see how to modify the Steinhaus proof though. When I open a window to air out the room, how does the smell disperse? Let's say I'm in a room with some kind of noxious stink, possibly of flatulent nature.  The quickest way to right the world that comes to mind is to open a window.  When I open a window, how do the stank particles leave the room?