how can i convert a 9.5 gb mkv file to mpg or avi with avconv?
Is FFmpeg missing from the official repositories in 14.04?
I'm working on this problem from Elementary Analysis by Ross which is intuitive when sketched but keeps stymieing me when I try to write it out.  Let $f$ be a continuous function on $[a,b] \subset \mathbb{R}$. Define $f^\star (x)$ as:  $$ f^\star(x) = \sup \{f(y)\mid a \leq y \leq x \} $$ Prove that $f^\star$ is a continuous increasing function on $[a,b]$.  Things I've figured out: (these are mostly trivial)   $f$ is uniformly continuous on $[a,b]$. Since $[a,b]$ is closed and bounded there exists some $c \in [a,b]$ such that $f(c) \geq f(x)\ \forall x \in [a,b]$. (In words: the supremum is actually attained.) If $c \in [a,b]$ is as above, then $f^\star$ is constant (and hence continuous) on $[c,b]$ (which is possibly a singleton).   This seems completely obvious when you actually draw a continuous function but translating that to a formal proof eludes me... Prove 24 divides $u^3-u$ for all odd natural numbers $u$ At our college, a professor told us to prove by a semi-formal demonstration (without complete induction):   For every odd natural: $24\mid(u^3-u)$   He said that that example was taken from a high school book - maybe I din't get something, but I really have no idea to prove that without using complete induction.  Any idea of smart demonstration?  Thanks for your help. (Excuse my bad English.) Why does 1+++2 = 3? How does Python evaluate the expression 1+++2?  How many ever + I put in between, it is printing 3 as the answer. Please can anyone explain this behavior  And for 1--2 it is printing 3 and for 1---2 it is printing -1 Why is it "come" rather than "go" ? Translation of words according to babel language I've got a template that is to be used in french or english, is there a name in babel defining the "of" of "page x of yy" than I want to translate automaticaly to "page x sur y"  If not, is there a way of setting a name according to language selected in babel. Do not load Facebook-based avatars directly from the Facebook CDN Users who register for their account via Facebook get  as their default avatar. However, the avatar is not copied to SE servers or Imgur, and thus the original URL is kept. This URL compromises the privacy of the user as it contains their Facebook user ID which everyone can easily extract and then view the profile.  The image is also not visible at all to those who have Facebook blocked for their own privacy (by extensions such as Ghostery or browser features ), or due to network policy (e.g. some work and school networks block Facebook).  With the new avatar system, it would be much better if the Facebook photo was stored like a manually uploaded avatar to avoid this problem. Disable or prevent multitouch in Activity How do I keep my character centred on screen? does not appear to actually define what a rigid shape is. Rather it defines 'same shape' and 'rigid transformations' without giving any definitions of what is necessary and sufficient for a shape to be considered rigid.  For instance, I've seen the following image:    I understand intuitively why the triangle is rigid and quadrilateral is non-rigid. It is also my understanding that inserting a single diagonal connection into the quadrilateral would make the shape rigid? However, given the following image (labeling the shapes $S_1$, $S_2$ and $S_3$ in sequence left to right):    If $S_1$ had a single diagonal connection AB, it would be possible to flip ADB over axis q to obtain a shape similar to $S_2$ with the addition of connection AB (my explanation may not be the greatest). This shape is clearly not the same as $S_1$, so how can we say $S_1$ with a single diagonal connection CD is rigid? I feel I am unclear on what the definition of rigidity actually is. Producing .bbl file with Lyx and JabRef How do I produce the .bbl file required for arXiv using JabRef for bibtex and Lyx? Extract substring in Bash Even though JRE 8 is installed on my MAC OS Yosemite, the error - " No Java Runtime present,requesting to install " How do I save a file with managed_file in a theme? I'm developing a theme that it requires to have a header image on the front page, so I have this.  casper.theme  function casper_form_system_theme_settings_alter(&amp;$form, &amp;$form_state) {  $form['theme_extra']['front_page_background_image'] = array(     '#type' =&gt; 'managed_file',     '#title' =&gt; 'Front Page Background Image',     '#description' =&gt; 'Add background image for the front page',     '#required' =&gt; FALSE,     '#weight' =&gt; -4,     '#upload_location' =&gt; file_default_scheme() . '://theme/backgrounds/',     '#default_value' =&gt; theme_get_setting('front_page_background_image' , 'casper'),     '#upload_validators' =&gt; array(         'file_validate_extensions' =&gt; array('gif png jpg jpeg'),     ),  ); }   However, after it, while the file been missing and after some reading, I find out that is because managed_file does not save your image permanent.   There are similar questions:    is specified to Drupal 7.  is using "file" type instead of managed_file. I already tried something similar to what the Mayo theme is doing, but I was not able to successfully figure it out.   How can I save my image permanently? Inverse metric in linearised gravity Proofs involving $ (A\setminus B) \cup (A \cap B)$ Give short arguments for each part below to complete the reasoning. Please do not use Venn diagrams.     a. Prove that $A = (A\setminus B) \cup (A \cap B)$.   (Hint: You should prove that $(A\setminus B)\cup (A\cap B) \subseteq A$ and vice-versa)      b. Prove that $(A \setminus B) \cap (A \cap B) = \emptyset$   (Hint: Try a proof by contradiction for this statement.).    I'm not too sure exactly where to start on this. Both statements make sense logically, but I don't know how exactly to prove them. Can anyone point me in the right direction? Motion Tracking objects that go out of frame and re-enter later I am motion tracking a video in which the camera turns away from one scene and then shortly returns to it. However, the segments that went off-screen lose their track and do not continue tracking once the camera returns. I am wondering if there is a manual way to tell a segment where and when to continue looking for it's tracking target. Is this possible to do? What happened to /etc/apt/apt.conf? 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. How to *disable* automatic reboots in Windows 10? Windows 10 lets you 'schedule' a reboot for later. I want to disable it.  Evidently Windows scheduled itself for a reboot last night when I wasn't looking and just closed everything I had been working on the night before.  I reboot on the regular; I don't need Windows to do that for me.  Can I disable it completely? I don't mind if it downloads everything, and then says "hey, you should reboot," but it should never reboot itself, ever.  I'm using the "Pro" edition of Windows 10. Is there a word that contains all the vowels? "Jealousy" contains most of the vowels but lacks 'i'. Is there a word in the English language that contains every vowel (and preferably 'y')? I recieve the below error when I am trying to call a Custom Lightning Component in a Visualforce page that is used in Communities.    Unrecognized Content-Security-Policy directive 'reflected-xss'.   logo180.png Failed to load resource: the server responded with a status of 404 (Not Found)   CommunityHomePage:1 Uncaught SyntaxError: Unexpected token w in JSON at position 0     at JSON.parse ()     at XMLHttpRequest.xhr.onreadystatechange (lightning/lightning.out.delegate.js?v=ZCuyRUYzK_kAf4cKCIeS2A:143)   My Component  &lt;aura:component controller="LeadController" implements="forceCommunity:availableForAllPageTypes"&gt;     &lt;aura:attribute name="theLead"          type="Lead"          default="{ 'sobjectType': 'Lead',                    'Rating__c': 2,                    'Company': '',                    'FirstName': '',                    'LastName': '',                    'Email': '' }"/&gt;     &lt;form&gt;          &lt;ui:inputText value="{!v.theLead.Company}" label="Company" class="input"/&gt;         &lt;ui:inputText value="{!v.theLead.FirstName}" label="First" class="input"/&gt;         &lt;ui:inputText value="{!v.theLead.LastName}" label="Last" class="input" /&gt;         &lt;ui:inputEmail value="{!v.theLead.Email}" label="Email" class="input" /&gt;         &lt;ui:button label="Save" press="{!c.save}"/&gt;     &lt;/form&gt; &lt;/aura:component&gt;   My Lightning App is   &lt;aura:application access="GLOBAL" extends="ltng:outApp" implements="forceCommunity:availableForAllPageTypes"&gt;     &lt;aura:dependency resource="c:CommunityChatter"/&gt; &lt;/aura:application&gt;   My VF Page is  &lt;apex:page standardController="Lead"&gt;     &lt;apex:includeScript value="{!$Site.BaseUrl}/lightning/lightning.out.js"/&gt;     &lt;script&gt;         $Lightning.use("c:MyLightApp", function() {             $Lightning.createComponent(                 "c:CommunityChatter",                 {},                 "theLead",                 function(cmp) {                     console.log("Component created!");                     console.log(cmp);                 });             });     &lt;/script&gt;      &lt;div id="theLead"&gt;&lt;/div&gt; &lt;/apex:page&gt;