Prove $\frac{|a-c|}{\sqrt{(1+a^2)(1+c^2)}}\leq\frac{|a-b|}{\sqrt{(1+a^2)(1+b^2)}}+\frac{|b-c|}{\sqrt{(1+b^2)(1+c^2)}}$
Metric $d(x,y)=\frac{|x-y|}{\sqrt{1+x^2}\sqrt{1+y^2}}$ on $\mathbb{R}$
I don't know much about this,  But I've some of the questions on which some user has answered (not helpful answer) also but I want to delete those questions, but whenever I go to delete that question. It is prompting with     What does it mean? Can someone tell me what would be the action taken by Stack Exchange if I delete more questions? Can I stay overnight [15-hour layover] in Haneda airport without a Japan visa? I’m a Filipino citizen. My flight goes from Vancouver to Manila via Tokyo Haneda. I will arrive in Japan at 6pm then depart at 9am the next day. I'm not planning to go out of the airport during my layover, so I don't see a need to have a transit visa. However, I called the Consulate-General of Japan here in Canada, and they asked me to get a transit visa.  Then I called the Ministry of Foreign Affairs in Japan and asked them the same question.. at first, they told me I don’t need a visa as long as I stay inside the airport, but when I told them that the Consulate-General of Japan in Canada asked me to get a visa, they also asked me to get one.  I'm so confused. I would like to know your knowledge or experience regarding this. I think this question is already answered anywhere, but I couldn't find a solution with my search terms :/ .  So I got this model and I only want to smooth out the cylinder parts, but not the extruded edges.  So here is my original model, I think it's kinda clear what should be smoothed out, it is supposed to become a rifle scope.    This happens with the normal smooth button, but I already tried it with a Bevel modifier and subdivison surface aswell.    Solution: Edge Split Modifier with Smooth: My computer no longer boots Windows or the installed operating system. Instead, I may get this error:  PXE-E61: Media test failure, check cable -or- Check cable connection!  PXE-M0F: Exiting PXE ROM.   and/or one of the following messages or similar:  Operating System not found  No boot device available- No bootable devices--strike F1 to retry boot, F2 for setup utility  No bootable device -- insert boot disk and press any key  No Boot Device Found. Press any key to reboot the machine  Default Boot Device Missing or Boot Failed  Reboot and Select proper Boot device or Insert Boot Media in selected Boot device   What does this mean and what can I do?     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details. Map a function across a list conditionally 'Search on Yammer' link in search center refiners I have a heavily branded site I'm working on and can't find where the "Search on Yammer" link is being populated from. It appears within the search refiner/filter web part in the left column but none of the display templates reference this.   I'd like to be able to customize the link, placement on the page, etc. without resorting to jQuery to move elements around the page.     And the markup coming through looks like this. The refiners themselves come through a series of display templates but the Yammer link is nowhere that I can see in any of them.   &lt;div webpartid="f09e98eb-6dc3-4a9b-8dbf-65d0fbc7b7c3" haspers="false" id="WebPartWPQ4" width="100%" class="ms-WPBody " allowdelete="false" style=""&gt;     &lt;div class="ms-ref-ctrl"&gt;         &lt;div class="ms-ref-refiner"&gt;             &lt;div id="Container"&gt;                 &lt;h2 class="ms-displayInline"&gt;                     &lt;a class="ms-ref-name ms-displayInlineBlock ms-srchnav-link-selected ms-link" href="javascript:void(window.open(                     'https://www.yammer.com/search?trk_event=o365_search&amp;amp;search='+                     encodeURIComponent(Srch.ScriptApplicationManager.get_current().queryGroups.                     Default.dataProvider.get_currentQueryState().k),'_blank'));" title="Open a new tab to search for this on Yammer"&gt;Search on Yammer&lt;/a&gt;                 &lt;/h2&gt;             &lt;/div&gt;         &lt;/div&gt;     &lt;/div&gt; &lt;/div&gt; &lt;div componentid="ctl00_SPWebPartManager1_g_f09e98eb_6dc3_4a9b_8dbf_65d0fbc7b7c3_csr" id="ctl00_SPWebPartManager1_g_f09e98eb_6dc3_4a9b_8dbf_65d0fbc7b7c3_csr"&gt;             ... refiners populated through display templates ... &lt;/div&gt; Regular Expression: Numeric range What is the weight equation through general relativity? In PostgreSQL is the row ordering preserved in functions and CTEs? How do I drop an object to the sand? Compiling LaTeX document empties .bbl file I'm trying out biblatex for the document I'm compiling, using the biber backend on my miktex distribution. Everything, including biber, should be up to date, assuming the MiKTeX repository currently holds the latest versions of everything.  This is what the biblatex documentation (p. 101) says about how often I have to run biber to update my .bbl file:     Whenever a reference to a work which has not been cited before is   added, this procedure must be repeated. This is also the case if the   last reference to a work which has been cited before is removed   because some citation labels may change in this case.   So if I make changes to my document (which is a very common activity in the process of writing a document), but leave the citations unchanged, I should not have to re-run biber before compiling the changes. However, every time I compile my document, regardless of the compiler or documentclass, the .bbl file is emptied. Consequently, the next time I compile the document without running biber, the bibliography is removed (seeing as the .bbl file contains nothing), and all my citations are broken. For this reason, I have to run biber before every time I compile the document, which largely counters the benefit of externalizing the bibliography in the first place.  How can I make the compilers stop overwriting my .bbl file and make everything behave as described in the biblatex manual?  Upon investigating the contents of the auxiliary files, I found that the .bbl file (after running biber, before compiling) begins with the following lines:  % $ biblatex auxiliary file $ % $ biblatex bbl format version 2.3 $   Does the biblatex version 2.8 still mark the .bbl files as version 2.3? If not, could this be the problem? And if so, why does my 2.8 version of biblatex (partly) behave as version 2.3?  Any help solving this problem would be much appreciated. I am starting to see a lot of people claiming that convential current is 'wrong' because Franklin made an error when he first started investigating electrostatics, and that later scientists didn't bother correcting the mistake, but preferred to keep the 'convention' (here is a classic example: )  I always thought he didn't get it wrong. He said that current is positive in the direction that positive charge flows, and vice-versa. He of course had no way to know which side of two sticks behind rubbed actually gained or lost mass. So he wasn't wrong. What were you taught?  P.S. I can't help but feel we are lucky that he got it 'backwards', because clearly many people are confused about electrostastics (including the author of that text book!) and believe electricity has to involve electrons (an unfortunate name... why couldn't they have been named negatrons...) This might be a bizarre but crucial question, can I fully trust leaving my laptop in repairs (Genius Bar) while they have full access to it ?  I recently went to the genius bar to get my display fixed, and apparently they asked for my laptop's password just in case they need some "testing" after they're done. Can't they do that as a guest account ?  I got sensitive information on my laptop such as passport copies etc, as well as passwords saved in Safari's keychains for my bank account, paypal, amazon etc ..  The service is due later on today, shall I change my password and ask them to contact me directly if they need something specific ?? They're going to fix in 3 hours so I'll be in the mall whilst they finish. "Thought you'd never ask" is "I thought you'd never ask" with "I" omitted. "Hope this helps" is "I hope this helps" with "I" omitted.   In English grammar, normally every sentence should have a subject, right?   My first thought is that these two examples are so often used that they are like set phrases. But these are not really set phrases. You can alter the words after "thought" and "hope".  Another possible explanation is the tendency to drop the subject if it is the first person pronoun. It seems that in many languages, such as Spanish, Italian and Japanese, the first person subject is usually omitted. Maybe English is going the same way? (Not exactly the same, since in Italian, verb forms change according to the person, so the subject is not necessary to understand who one's referring to.)  And, apparently, such omission is more common in spoken English than in written English.  Are there more examples of such first person subject omission? How frequent is it? Is Dirichlet function Riemann integrable? "Dirichlet function" is meant to be the characteristic function of rational numbers on $[a,b]\subset\mathbb{R}$.   On one hand, a function on $[a,b]$ is Riemann integrable if and only if it is bounded and continuous almost everywhere, which the Dirichlet function satisfies.  On the other hand, the upper integral of Dirichlet function is $b-a$, while the lower integral is $0$. They don't match, so that the function is not Riemann integrable.  I feel confused about which explanation I should choose... Hibernate @Enumerated mapping I have recently installed Ubuntu 14.04 LTS on my laptop Sony Vaio VPCEA16FG. I have been getting system freezes (everything including display, mouse, keyboard stops working and I have to do a restart with the power switch) and there are random popups of "System program problem Detected"  On startup my screen is all splashed with black and white pixels and a System program problem detected message.  My video card info:    01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Madison [Mobility Radeon HD 5650/5750 / 6530M/6550M What is the name of the depiction of concentration with raised eyebrow called? Delete all files to which no corresponding file with another extension exists My goal is to find a Linux command sequence, which deletes some files if a special condition is fulfilled:  All files with the extensions .cut or .cut.bak in the current directory shall be removed, IF there is no file having the same name, but extension .rec or .mpg in the current directory.  Background: I am developing a tool for a Linux-based PVR, that allows cutting of recorded programs. For each recording (extension .rec or .mpg) the segment markers are stored in a .cut-file with the same name. When some recording gets moved/renamed/deleted, then the corresponding cut-file remains orphaned and shall be deleted. I already have implemented the removing of those useless cut-files in C. But I am wondering, whether there may be a (simple) system based solution. In this case it could be run via 'system' and &amp; in the background, which would make my application more responsive...  I already asked a similar question for the recursive case (browsing also into subdirectories), . There has been a (nearly) perfect answer by kos - but unfortunately it removes too many files, so it is not usable, and I was not able to figure it out... But the same idea can be used here, IF it is possible to parse and pipe the result of 'ls' linewise... HTTP request parameters are not available by request.getAttribute()