Is a metric space complete?
About compactness and completeness of set $X = \mathbb{R}$ with the metric $d(x, y) = \frac{|x-y|}{1+|x-y|}$
Avoiding getting suspended for voting irregularities? Many times when I read threads, I keep on upvoting for the reason being that if someone has put an effort to write a big answer, s/he/it should get some rewards for it.  I recently saw someone getting suspended for voting irregularities.   So, I was wondering if I use the total amount of votes allowed per day, daily, will I be suspended? Detect the Internet connection is offline? How to detect the Internet connection is offline in JavaScript? I wish to calculate the volumes of a truncated cone whith asymetry over all axes and ellipses as base and top - how do I do that?  I have height and radii of the corresponding ellipses. (I assume correctly I need the geometric means of the 2 radii describing the ellipsis.)  Kind Regards I've recently searched how I could get the application's directory in Java. I've finally found the answer but I've needed surprisingly long because searching for such a generic term isn't easy. I think it would be a good idea to compile a list of how to achieve this in multiple languages.  Feel free to up/downvote if you (don't) like the idea and please contribute if you like it.  Clarification:  There's a fine distinction between the directory that contains the executable file and the current working directory (given by pwd under Unix). I was originally interested in the former but feel free to post methods for determining the latter as well (clarifying which one you mean). The parmesan cheese in pasta recipe is quite expensive.....do we have cheaper alternative??  Are there are cheddar cheese which can replace parmesan cheese? OS: Windows 7. I want install Linux Ubuntu on portable external Hard Drive USB 2.0. I read a variety of methods, but I'm confused by contradictory advices and methods. Actually, installing Ubuntu on anything other than clean PC looks much more complicated than installing Windows. I need to have Ubuntu package + Python 2.7 + C compiler installed. My external hard drive is partially filled, I need to keep all files.   Will Ubuntu run entirely on external hardrive, without writing anythinhg to Windows system folders and to registry?  Can anyone post detailed guide how install Ubuntu on external hard drive? Setting time limit php Why is Tony Stark in the Iron Man suit unaffected by G-forces, inertia and blunt force trauma? Tony's suit is an engineering marvel, and they explain many facets of the technology to help give legitimacy to the special powers, abilities and weapons it has.  I never read the Iron Man comics, but in the movie they really don't have a technological explanation for how he miraculously seems to be unaffected by crushing G-forces of sudden acceleration, the inertia of sudden stops and hair-pin turns, and especially the blunt force trauma from getting smashed in the face with Thor's hammer.  Certainly it appears the suit takes punishment, but Tony always remains unscatched, never a collapsed lung, broken bone or even a bloody nose.  In my infantile understanding of theoretical physics, the same technology that would be used to counter G-forces and sudden blunt force trauma to the body inside would be the very same technology used for  which in my honest opinion would be a much more stunning technological achievement than his heralded Arc Reactor.  Was their ever an explanation proferred for this and if so was it indeed attributed to Anti-Gravity? Now that I'm looking into home automation, I'm thinking about automatically cutting off the fridge power from 3am ~ 5am. Given that modern refrigerators are well insulated, it should be able to withstand 2 hours of non powered cooling.  If I proceed with this project, will I see a big reduction in my monthly electrical bill? The title says it all. I want to resize windows with an right click while holding the alt key, instead of the new default alt+middle click.  I have found no way to enable this behaviour in 13.04. The gconf-Key suggested in this , doesn't seem to exist any longer. With an  of archive/compression file formats, is there a single free/open-source command line tool to rule them all? Perhaps something with a consistent / unified set of flags? (note my  friendly )  I once run into a set of aliases meant to largely simplify the task of compressing/de-compressing files with bindings to tar and other utils, but I can't find this anymore.  Update: How can I configure something like atool to not use unzip to extract zip files (which apparently can't handle files larger than 4GB) and to use gunzip instead?  $ aunpack large_file.zip error:  Zip file too big (greater than 4294959102 bytes) Archive:  large_file.zip warning [large_file.zip]:  1491344848 extra bytes at beginning or within zipfile   (attempting to process anyway) error [large_file.zip]:  start of central directory not found;   zipfile corrupt.   (please check that you have transferred or created the zipfile in the   appropriate BINARY mode and that you have compiled UnZip properly) aunpack: unzip ...: non-zero return-code How long does it take for badges to be awarded? How are they generated? Do badges get calculated in real time, or do they get calculated by an external service? How long does it take for a badge to be awarded, once its requirements are met?  Does Stack Overflow use any external services to do things, like maintenance, e-mailing or badge calculation? Only half of the display works, can I set to display only in that region? I have a Macbook with a cracked screen, only the top left half of the screen works, is there anyway to reduce the screen resolution, keep the DPI the same, and thus have the entire OS visible in the top left section of the screen which works?  The below photo demonstrates what I mean, with parts of the creen totally unusable, it would make sense to be able to display the whole screen in the remaining usable part. Zero-pad digits in string How to remove the “AMD Testing use only” watermark? I've installed the  (beta) following the step in  for Ubuntu Quantal Quetzal. My system is 64 bit and my graphic card is an ATI RadeonHD 6670, this g.c. is Officially Supported (Catalyst &amp; Open Source), you can confirm that from this .  I don't have any problem, except the AMD testing use only watermark. I see the following frame in any stage into the OS (logged, unlloged, etc.) except in the terminals.     I found different versions of how to remove this image, but this change according to the system, so I want an answer from this popular (trusted) site.   How to solve this issue in Ubuntu 12.10 32b? This procedure is different in a 64b system? Pause button started working for Chrome / Youtube, messing with audio player controls Second law of Newton for variable mass systems Frequently I see the expression  $$F = \frac{dp}{dt} = \frac{d}{dt}(mv) = \frac{dm}{dt}v + ma,$$ which can be applied to variable mass systems.  But I'm wondering if this derivation is correct, because the second law of Newton is formulated for point masses.   Furthermore if i change the inertial frame of reference, only $v$ on the right side of the formula $F = \frac{dm}{dt}v+ma$ will change, meaning that $F$ would be dependent of the frame of reference, which (according to me) can't be true.   I realize there exists a formula for varying mass systems, that looks quite familiar to this one, but isn't exactly the same, because the $v$ on the right side is there the relative velocity of mass expulsed/accreted. The derivation of that formula is also rather different from this one.   So my question is: is this formula, that I frequently encounter in syllabi and books, correct? Where lies my mistake. How to overload __init__ method based on argument type? Proving $\sqrt{2}+\sqrt[3]{3}$ is algebraic. Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive? Imagine I have tons of RAM. Let's say 64GB. That's a lot for even gaming PCs. Now the default location of a pagefile in Windows is on the main OS drive, be it HDD or SSD, which are faster in general, but still not as fast as RAM.  Something tells me that disabling the pagefile on the hard drive or creating a virtual RAM drive and letting the pagefile be there could make Windows move all its virtual memory to RAM, and so increase the system's performance, but I'm not very knowledgeable in that area, so that might not be true at all.  I tried both, but I couldn't analyze the results to reach a definite conclusion with my knowledge level in memory things.  Would this work? If not, why?