I want to visualize constructing (sliding & press fitting) a few multiplex panels into a table or stool. The shapes of these panels can be provided in SVG or DXF. The svg is . I tried to extrude that shape using  (skipping the inkscape part).  I only seem to be able to extrude the borderlines of the elements not the surface of the element, also the holes don't look like holes. I made sure that the SVG-paths are closed, but still not the desired output.

I'm having a big problem with the bezier curves in Blender. I'm trying to fill up the curves, but I can't. I have already seen some videos from YouTube, that say that I have to click on the 2D button.    But when i click on the 2D button, this is what it happens.    I thought it was a problem with the camera, but:    What am I doing wrong?


I have struggled to find a solution to be able to clip an OpenStreetMap (OSM) raster layer but still run functions using plugins such as ORS Tools. I would like to clip OSM with an overlaying vector layer, but not for aesthetic purposes. I have seen solutions where you convert the OSM raster layer into an image, but this would get rid of information contained in the original layer. With my clipped OSM layer I would like to be able to run a route analysis / network analysis of the roads in my study area. The reason for clipping the OSM is because there are certain stretches of roads that I want the plugins to avoid when calculating the shortest route. Plugins for QGIS such as ORS Tools and TravelTime allow network analysis but I believe they do this (please correct me if I am wrong) by using road and route data through their own databases. Is there a way I can clip an OSM layer (or something similar) in QGIS and then be able to calculate the shortest route between two points using only the roads on this newly clipped layer? If you know of a solution for Esri I would be happy to give that a go too.

In QGIS I am analysing the flooding of road networks. I have created a vector line layer of all the stretches of roads in my study area where high risk flood extent areas intersect them. I now want to see which deprived areas would be most impacted by calculating the shortest route to essential services (avoiding these flooded roads). I have polygon layers of regions of deprived communities and point layers of hospital locations. Is there a plugin or function in QGIS that allows me to calculate the shortest route (and the time it takes, if possible) to the nearest hospital from the edge of a polygon, avoiding these flooded roads (line layer)?


I just wondering how modems work.   I know the process of "modulation" and "demodulation".  So I wanto know is "demodulation" are simple revese of "modulation" in real world.  The PC can got an IP address when connect as type 1  What will happen when I connect them like type 2?     type 1 :      [PC] ================= [router]      type 2 :      [PC] === [m] ------- [m] === [router]      [m] : modem(exactly same)      === : Ethernet cable      --- : DSL cable (phone line, maybe optical fiber, or something else?)   ISP has a large number of model, Is them same thing as the one in my home(but with diffrent size/speed/price...etc)? Or it's completely different thing?

I'd like to capture the data sent by my ADSL modem (what's really sent on the RJ11 cable). I have no access to my modem (no ssh), so I'd like to build a mini-computer with 2 RJ11 plug, one connected to the modem, one to the telephone plug, and be able to capture/edit the data sent and recieved.  Somebody knows where I should start ?


I use zxing to encode a qr code and store it as a bitmap and then show it in ImageView. Since the image generation time is significant I'm planning to move it to a separate thread (AsyncTaskLoader will be fine I think).  The problem is - it's an image and I know that to avoid memory leaks one should never store a strong reference to it in an Activity.  So how would you do it? How to cache an image to survive config changes (phone rotation) and generally avoid generating it onCreate()?  Just point me in the right direction, please.  EDIT: Or maybe, if I use AsyncTaskLoader anyway, I should let it do its job and keep the Bitmap there? I mean, it's supposed to return the data it's loaded (generated in this case) and return it when needed, isn't it?

I am using a ListView to display some images and captions associated with those images. I am getting the images from the Internet. Is there a way to lazy load images so while the text displays, the UI is not blocked and images are displayed as they are downloaded?   The total number of images is not fixed.


I got an notice that some clients werent receiving their emails, all clients used hotmail accounts, while i looked into logs i got this part  Sep 25 07:52:51 s22090 named[25045]: client 127.0.0.1#44056: query (cache) 'hotmail.com/MX/IN' denied Sep 25 07:52:51 ...#56174: query (cache) 'mx2.hotmail.com/A/IN' denied Sep 25 07:52:51 ...#59417: query (cache) 'mx2.hotmail.com/AAAA/IN' denied Sep 25 07:52:51 ...#54682: query (cache) 'mx1.hotmail.com/A/IN' denied Sep 25 07:52:51 ...#60299: query (cache) 'mx1.hotmail.com/AAAA/IN' denied Sep 25 07:52:51 ...#54353: query (cache) 'mx4.hotmail.com/A/IN' denied Sep 25 07:52:51 ...#55171: query (cache) 'mx4.hotmail.com/AAAA/IN' denied Sep 25 07:52:51 ...#55501: query (cache) 'mx3.hotmail.com/A/IN' denied Sep 25 07:52:51 ...#33547: query (cache) 'mx3.hotmail.com/AAAA/IN' denied Sep 28 06:39:52 ...#52626: query (cache) 'd7ddfeb7120a9845bbb8f56e789c4f.pamx1.hotmail.com/A/IN' denied Sep 28 06:39:52 ...#44450: query (cache) 'd7ddfeb7120a9845bbb8f56e789c4f.pamx1.hotmail.com/AAAA/IN' denied   Which i cant really understand why it blocks/denies, anyone can help?  edit  Return-Path:    <spedeus@s22090.vps.name-servers.gr> X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on s22090.vps.name-servers.gr X-Spam-Level:   ** X-Spam-Status:  No, score=2.4 required=5.0 tests=HTML_IMAGE_ONLY_20, HTML_MESSAGE,HTML_MIME_NO_HTML_TAG,MIME_HTML_ONLY,NO_RELAYS autolearn=no version=3.3.1 X-Original-To:  info@spedeus.com Delivered-To:   info.spedeus@s22090.vps.name-servers.gr Received:   by s22090.vps.name-servers.gr (Postfix, from userid 507) id 3BDC9192511F; Wed, 7 Oct 2015 14:35:57 -0400 (EDT) To: info@spedeus.com Subject:    xxxxx X-PHP-Originating-Script:   507:class.phpmailer.php Date:   Wed, 7 Oct 2015 14:35:57 -0400 From:   "Spedeus.com" <noreply@spedeus.com> Message-ID: <b1ea97c7e45bfc0362e77ee9d6470b0c@www.spedeus.com> X-Priority: 3 X-Mailer:   PHPMailer 5.2.1 (http://code.google.com/a/apache-extras.org/p/phpmailer/) MIME-Version:   1.0 Content-Transfer-Encoding:  8bit Content-Type:   text/html; charset="UTF-8"   the DNS records  mail    A - IPv4 Address    185.25.22.90 spedeus.com MX - Mail Server    5 mail.spedeus.com. spedeus.com SPF - Sender Permitted From v=spf1 a mx a:spedeus.com ip4:185.25.22.90 ?all   edit2  Oct  8 05:33:24 s22090 postfix/pickup[13686]: 9AD7619265B0: uid=0 from=<info@spedeus.com> Oct  8 05:33:24 s22090 postfix/cleanup[15659]: 9AD7619265B0: message-id=<1444296804.15654@spedeus.com> Oct  8 05:33:24 s22090 postfix/qmgr[13687]: 9AD7619265B0: from=<info@spedeus.com>, size=602, nrcpt=1 (queue active) Oct  8 05:33:26 s22090 postfix/smtp[15661]: 9AD7619265B0: to=<xxxxx@hotmail.com>, relay=mx4.hotmail.com[65.55.37.104]:25, delay=2.1, delays=0.12/0.01/0.64/1.3, dsn=2.0.0, status=sent (250  <1444296804.15654@spedeus.com> Queued mail for delivery) Oct  8 05:33:26 s22090 postfix/qmgr[13687]: 9AD7619265B0: removed   As i see, it gets removed from queue after queued for delivery.

This is a  about how to handle email sent from your server being misclassified as spam.  For additional information you may find these similar questions helpful:                    Sometimes I want to send newsletters to my customers. The problem is, that some of the emails get caught as spam messages. Mostly by Outlook at the client (even in my own Outlook 2007).  Now I want to know what should be done to create "good" emails. I know about reverse lookup etc., but (for example), what about a unsubscribe link with an unique ID?  Does that increase a spam rating?


I lost my iPhone 6s that isn't signed into iCloud. So, in turn, I can't use 'find my iPhone' or call the iPhone, because I haven't yet assigned a phone number to it. I did sign into the phone, though. Just not iCloud. Is there any way to find my 6s?

My father has lost his iPhone 6 which was not signed in using an iCloud account. Is there any possibility it can be found?


We need to find out the maximum no-adjacent subset-sum in the given array,     no-adjacent: we cannot pick adjacent elements while forming the   maximum subset-sum.   For example:  arr = [5, 3, 7, 14]  Solution : [5, 14] : 19 maximum sum  Explanation:  5 and 14 are not adjacent numbers and their sum is maximum.  Code  int main(){     //input    int n;    cin>>n;    vector<int> arr;    while(n--){       int x;       cin>>x;       arr.push_back(x);    }     int max_adj = INT32_MIN;     for (int i = 0; i < arr.size(); i++)       max_adj = max(max_adj, maxSum(arr, i));   }   int maxSum(vector<int> &arr, int vidx) {     if (vidx >= arr.size()) {        return 0;    }     int max_ = 0;     for (int i = vidx + 2; i < arr.size(); i++) {        max_ = max(max_, maxSum(arr, i));    }     return max_ + arr[vidx]; }   The above approach is a brute force/naive recursive approach to solve this problem. I know there exists a better dp solution.  But, I am just looking for a way how to find out the     Big O time complexity   of this recursive solution mathematically.

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


This is really driving me up the wall now.  Randomly, all my menu items for all menus are just being deleted on their own. Not the menus themselves but all items within them.  This is a custom theme we built upon the Bones boilerplate. We've built plenty of sites on Bones though and we're not experiencing the problem with any others.  I know the usual advice will be:-   Deactivate all plugins and see if the problem persists. Revert to the default Wordpress theme and see if the problem persists.   But this isn't particularly practical as it means breaking our website for weeks on end waiting to see whether the problem occurs again.  Each time this happens, we have to manually rebuild all our menus and it is becoming a real pain now plus potentially catastrophic if Google crawl our website when these menu items have all been deleted.  This only started happening since the 3.8 update but occurs within four days of reinstating all the menu items again.  There is nothing of note in the error logs. This last happened in the past 48 hours and all we have in the error log from this period is the following (actual domain replaced with domain.com):-  [Sun May 25 02:32:23 2014] [warn] RSA server certificate CommonName (CN) `plesk' does NOT match server name!? [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/vhosts/domain.com/cgi-bin/php [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/vhosts/domain.com/cgi-bin/php5 [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/vhosts/domain.com/cgi-bin/php-cgi [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/vhosts/domain.com/cgi-bin/php.cgi [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/vhosts/domain.com/cgi-bin/php4 [Tue May 27 04:10:55 2014] [error] [client 188.143.234.90] script not found or unable to stat: /var/www/cgi-bin/cgi_wrapper/php   If all anyone can suggest is the above bullet points, then all I can really think of is to replicate the website in a dev environment and noindex the site for web crawlers (I've asked in various communities already) - there does seem to be a few other people that have experienced the same problem with little idea of resolution although for some it seemed to be related to plugins (although I don't have those plugins installed on our website).  Frustrating! Can anyone shed some better light on how to get to the bottom (debug) of this one?  I've just found  on here as well...  The database has been repaired as well to no avail.

Since yesterday the wp_scheduled_auto_draft_delete cron job somehow deletes all page entries from our menus. All entries in the table wp_postmeta with meta_key = '_menu_item_object' and meta_value = 'page' get deleted in the process. By tracing back the DELETE query I found out that the menu entries are deleted by a function called _wp_delete_post_menu_item. I got the following stacktrace for that function:  #0  _wp_delete_post_menu_item(3244) #1  call_user_func_array(_wp_delete_post_menu_item, Array ([0] => 3244)) called at [/srv/www/htdocs/biva/wp-includes/plugin.php:470] #2  do_action(delete_post, 3244) called at [/srv/www/htdocs/biva/wp-includes/post.php:2483] #3  wp_delete_post(3244, 1) called at [/srv/www/htdocs/biva/wp-includes/post.php:5645] #4  wp_delete_auto_drafts() #5  call_user_func_array(wp_delete_auto_drafts, Array ()) called at [/srv/www/htdocs/biva/wp-includes/plugin.php:546] #6  do_action_ref_array(wp_scheduled_auto_draft_delete, Array ()) called at [/srv/www/htdocs/biva/wp-cron.php:100]   But I'm stuck here, I'm not a wordpress developer and I have no clue why deleting old drafts results in deleting attached menu entries although the main pages still exist.  Workaround: As a workaround we added the following to the top of wp-config, wich will disable wp-cron:  /** Disable wp-cron to prevent menu from getting deleted. Detailed Bug description: http://wordpress.stackexchange.com/questions/145953 **/ define('DISABLE_WP_CRON', true);   If you are experiencing similar difficulties you might try locking the rows in the table wp_postmeta with meta_key = '_menu_item_object' and meta_value = 'page' and then tracing back the error message when WP trys to delete these rows, that's how we nailed down our error.  Reproduce the Error: It is definitely the stealth publish plugin that is causing our error, one can easily reproduce it, by doing the following:   Install a fresh Wordpress 3.9.1. Install the stealth publish plugin . Create a few test pages and add them to a new menu. Create a new page, with some dummy content, but do not save it!. Leave the page without saving. Change the system time 8 days into the future. The wp_scheduled_auto_draft_delete cron job will run because it runs daily and it hasn't run for 7 days as soon as you visit your page. It will then find your never saved dummy page delete it as it is older than 7 days and the menu will vanish. You might need to refresh the page a few times till the effect becomes visible.   I've recorded a screencast on how to reproduce the error (but I took not the time to comment it):


I am trying to truncate the text in a paragraph. Paragraph has span tags inside so the script which I have written is counting the text inside the paragraph (including span tag content).   And end result (rendered text) is eliminating the span tag (I need to apply different style for span tag text so it is mandatory to retain the span tag).  So how do I count only direct content of paragraph but not the span text inside it.  Here is the script  used for truncation      var showChar = 50;     var moretext = "more...";     var lesstext = "less";     $('p').each(function() {         var content = $(this).text();          if(content.length > showChar) {              var c = content.substr(0, showChar);             var h = content.substr(1, content.length - showChar);              var html = c + '' + h + '&nbsp;&nbsp;' + moretext + '';              $(this).html(html);         }         });       $(".morelink").click(function(){         if($(this).hasClass("less")) {             $(this).removeClass("less");               $(this).html(moretext);         } else {             $(this).addClass("less");             $(this).html(lesstext);         }         $(this).parent().prev().toggle();         $(this).prev().toggle();         return false;     });

I would like to get all descendant text nodes of an element, as a jQuery collection. What is the best way to do that?


When I try to upgrade firefox on Ubuntu I get this message in the terminal  E: Type '$' is not known on line 1 in source list /etc/apt/sources.list.d/brave-browser-release-bionic.list E: The list of sources could not be read. E: Type '$' is not known on line 1 in source list /etc/apt/sources.list.d/brave-browser-release-bionic.list E: The list of sources could not be read.

Every once in a while I see users having issues to update due to errors like this:  E:Type 'ain' is not known on line 1 in source list /etc/apt/sources.list.d/some-ppa.list'   with varying types/line numbers/source list files (often after removing a PPA).  How can such an error be fixed?


I was told it's a bad practice to have both bottom navigation and tabs in the same screen, but I'm not finding any information about why, and what can I use instead of tab bars in Material Design. The Google Play app has both for some reason. I'm developing an app for Android and my home screen looks like this. Thanks!

Prototyping a new dialer app based on Material's framework and style guide. Side navigation is not an option. Instead, I would like to use bottom navigation for 4 main pages/features.   Recent Calls Dialer Contacts (Just a button for the sub-pages)  3.1 All Contacts  3.2 Favorites  3.3 International Contacts Settings   "Contacts" page is actually 3 pages/tabs of 3 types of contact. So my problem is how to display the 3 contact types in the navigation system that suppose to base on Material?  This is the "International" tab example.


I am trying to use the qgsAffine plugin to do the transformation but I have no idea in its usage.   How to find the transformation parameters? I found some posts suggest using the OpenJump How to use the plug-in? I found my plug-in UI does not match with my found in Google. Why?   Here is my coordinates:   Original x 0.3704 (EPSG:4326) to Target long 114.2031 Original y 0.52804 (EPSG:4326) to Target lat 22.3249

I have a vector floorplan (DXF) that I've added to a blank project in  using the Dxf2Shp plugin.   I've been reading tutorials and StackExchange threads, but I can't seem to find out how to "georeference" my layer?  I'm assuming I can somehow select the corners of the building and set the lat/long.  My goal is to export a shapefile that I can use with  and .  I realized that the project coordinates were actually lat/long coordinates:    and I need to use the "Affine (Rotation, Translation, Scale)" plugin to "place" my CAD drawing.


which one is better? at a glance optional parameter seems better (less code, less XML documentation, etc), but why do most MSDN library classes use overloading instead of optional parameters?  Is there any special thing you have to take note when you choose to use optional parameter (or overloading)?

I was watching , and it got me thinking about when optional parameters are available in C# what is going to be the recommended way to declare methods that do not need all parameters specified?  For example something like the FileStream class has about fifteen different constructors which can be divided into logical 'families' e.g. the ones below from a string, the ones from an IntPtr and the ones from a SafeFileHandle.  FileStream(string,FileMode); FileStream(string,FileMode,FileAccess); FileStream(string,FileMode,FileAccess,FileShare); FileStream(string,FileMode,FileAccess,FileShare,int); FileStream(string,FileMode,FileAccess,FileShare,int,bool);   It seems to me that this type of pattern could be simplified by having three constructors instead, and using optional parameters for the ones that can be defaulted, which would make the different families of constructors more distinct [note: I know this change will not be made in the BCL, I'm talking hypothetically for this type of situation].  What do you think? From C# 4.0 will it make more sense to make closely related groups of constructors and methods a single method with optional parameters, or is there a good reason to stick with the traditional many-overload mechanism?


I just recently found out about the cheat codes for this game, and the sites I've viewed have three listed:      NotIt!!!11  Inv1s1bleEv3ryth1ng  <477MYFR13NDS4R3SP13S>   Does Goldeneye Wii have any other cheat codes?

I know that the game hasn't even been out for a week, but does anyone know if any cheat codes have been released by Activision yet?  I know that they must exist since there is a cheat codes menu within the game.


I have an old Vivanco MX300 mixer which runs of a 9v battery.  I have it in the same place and it's an inconvenience having it run by batteries. Could I use an old AC/DC adapter that would supply 9v at 1A or will it blow my desk.

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.


i have following code where i m including my title and description for the page But google crawled only title not the meta description from the code. Where as meta description was read from the keywords present in html of the page.. Please guide me guys where i m coding wrongly  <!DOCTYPE html>  <html> <head> <title>title inserted here</title> <meta http-equiv="Content-Type" content="text/html;charset=utf-8"> <meta name="description" content="description here"/>

I have unique meta descriptions on each of my pages, and when I search my site in google it will come up with no description.  Any idea what I might have done wrong?


I want to test the memory of my video card because there are vertical lines on my screen. I have done some basic troubleshooting and it seems that the problem is in the video card. I want to validate that the issue is the video card by testing its memrory. I have found software that is used for Nvidia cards with CUDA support, but my card is the Nvidia GeForce 7600, which has no CUDA support.

I run MemTest86 a lot at work on customer's machines, and it's great for troubleshooting memory issues. My question is, how can I test that a GPU is starting to go?  I know of programs like 3DMark to push the graphics card to its limits, but what about with Video Memory? Is it worth testing? Is there a stress tool actually able to catch issues in the video card (memory), perhaps using CUDA/OpenCL?


Today I set up an old portable pc to be a dedicated machine  I have installed debian and at installation process I have chose Cinnamon for graphical interface  Now my system is configured and working fine  I want to have access to this machine only with ssh and I dont want to have access to Cinnamon or every type of interface to keep every performance in process and not for graphique  It's possible to do that ?

I have a remote machine running Debian 8 (Jessie) with lightdm installed. I want it to start in no-GUI mode, but I don't want to remove all X-related stuff to still be able to run it though SSH with the -X parameter. So how to disable X server autostart without removing it?  I tried systemctl stop lightdm, it stops the lightdm, but it runs again after reboot. I also tried systemctl disable lightdm, but it basically does nothing. It renames lightdm's scripts in /etc/rc*.d directories, but it still starts after reboot, so what am I doing wrong? And I can't just update-rc.d lightdm stop, because it's deprecated and doesn't work.


I have arc desktop 10.3.  I have a feature class (nycd) with 59 records in it.  I'm trying to create a simple map with an inset that shows where each community district is located in that borough. I'd like to create an individual feature class for every record (with every field included) and put them in a file geodatabase (Comm_Snap) and am looking for different ways to do this. I'm not very familiar with arcpy but want to start utilizing it. I was initially thinking a simple script with a Search Cursor and a data management tool would work. Any suggestions?

I have a feature class with over 2,000 features, and I need to make them all individual feature classes based on a field.   Is there a way to do this?


Just tried installing Ubuntu for a class, but during installation it could not detect my Windows 8 operating system. It has a few options on what to do but I don't want to ruin my new computer. Please help.

I've been trying to install 12.04 for a while now, I'm running on Windows 7 and I already made the partition (it's dynamic). I've tried booting from a disc and also the Windows installer. I haven't tried used any repair-boot programs or anything. Every time I tried to load from either, I get an error:  command=C:\windows\sysnative\bcdedit.exe /set {03f9077f-661f-11e1-845a-d08b36406c3d} device partition=U;  retval=1  stderr=An error has occured setting the element data. The request isn't supported  stdout=   Then after that, it makes a log file with information that I don't understand.  If it is simply due to the fact of it being a dynamic partition, someone please help. If it is more extensive, anyone with details on possible solutions or definite ones please express them.


Legolas, the elf from Mirkwood, never runs out of arrows in any of the Lord of the Rings or Hobbit movies except the Battle of the Five Armies. How come that's the only one? How does Legolas always have an endless amount of arrows, except in that movie?

In the movie version of Lord of the Rings, Legolas is seen many times shooting arrow after arrow, yet he never seems to run out.  For example, after the long battle at the end of The Fellowship of the Ring, his quiver is completely filled.  Where are all these arrows coming from? Is it some form of elven magic? If so, it is never explained either in the movie, nor in the book that I can recall.


Let $X$ be complete and $f:X \to Y$ bilipschitz. Show that $f(X)$ is complete.  Since $f$ is bilipschitz we have $$\frac1Md(x,y) \leqslant d(f(x),f(y)) \leqslant Md(x,y).$$ Now also note that $f$ is injective. Now as $X$ is complete let $(x_n) \in X$ be Cauchy. By injectivity we have that $f(x_n)=y_n \in f(X).$ Now in order for $f(X)$ to be complete we need to show that $(y_n)$ is Cauchy and it converges. How can I show these two statements? I assume I have to use the bilipschitz property here somehow?

Let $\phi : E \to E'$ be a bi-Lipschitz map between metric spaces. Show that $E$ is complete if and only if $E'$ is complete.   I'm unsure of how to construct this proof. I know from a previous exercise that if $(x_n)$ is a Cauchy sequence in $E$, then $(\phi(x_n))$ is a Cauchy sequence in $E'$, if required.   Many thanks!


I am trying to find out a thomas cook flight number which was supposed to fly out of tenerife to UK (Manchester?) on friday 25th feb 2011 but did not go till saturday 26th.

How can I find an old flight number from over three years ago? I am trying to make a claim for a delay of over five hours. They sent us to the wrong destination and lost our luggage.


Doesn't flux mean the measure of flow of something  represented by vector A. But in the case of an electric field we have nothing that actually flows . So how can we use the idea of flux while dealing with electric fields

Can you please explain me what is electric flux. I know it is $\int\mathbf{E}\cdot\mathrm{d}\mathbf{S}$, but in many place its given flux means to flow. But how does electric field "flow"? Also if we assume its the electric field lines (can you also specify what exactly are these) are "flowing" how does $\int\mathbf{E}\cdot\mathrm{d}\mathbf{S}$ give the total electric field lines passing through that area? (can you please elaborate when you explain?)  Pls. I know it shouldn't come here but there is no page for electric flux.


Someone recently asked about the false claim that a movie was based on a true story. I often wonder about the opposite claim: Any resemblance to actual persons living or dead is entirely coincidental. It is strange that this message often appears after a film in which such a resemblance is obviously not entirely coincidental. Apparently this affords some kind of legal protection anyhow?

What would happen if shows like South Park would remove their introductory disclaimer like message like 'all celebrities are impersonated...poorly'etc. before the show stars. What could happen to them legally? Would they be allowed to and how bad would it be?


I'm wondering if it's possible to fake keydown and keyup events in javascript with for example a button? So when a button is clicked (or in my case tapped) it sends keycode 32 or whatever to the browser?

Is it possible to simulate key press events programmatically in JavaScript?


#!/bin/bash # echo $PWD cd /home/<my username>/<long path> echo $PWD   What I get when executing it with bash script.sh:  /home/<my username> : No such file or directorye/<my username>/<long path> /home/<my username>   Or with bash . script.sh  .: .: is a directory   It looks like in first case it has just skipped first 4 characters (/hom) of the address line for no reason. And in second case, what the hell is .: .:? It's absolutely "ungooglable".  And ofc when I copypaste this line cd /home/<my username>/<long path> in terminal it works like it should.  EDIT: IT WAS ALL ABOUT ONE MISSING SPACE SYMBOL AT THE END OF THE PATH, THANK YOU.

I've written a bash script which should cd me to a directory.   My problem is that only the directory in the subshell changes.  I've read of many similar problems to this, but I want to know if there is a solution besides using an alias, a function or sourcing the script.  If you don't understand what I mean, here's an example:  user@linux ~: cat ./myscript.sh #!/bin/bash cd /any/directory user@linux ~: ./myscript.sh user@linux ~:    Please note that my script is much longer, so I don't want to use a function!


Show that if $a,b,c,d \in \mathbb R$ and at least one is different from $0$, then   $$\begin{vmatrix} a & b & c & d\\  b & -a & d &-c \\  c & -d & -a &b \\  d & c & -b &-a  \end{vmatrix} \neq 0$$

I need to calculate the following determinant in order to prove the following equality:  $$\det\begin{pmatrix} a & b & c & d \\ -b & a & -d & c \\ -c & d & a & -b \\ -d & -c & b & a \end{pmatrix} = (a^2+b^2+c^2+d^2)^2.$$  I tried using Gauss-algorithm to get an easier matrix, but I'm not sure if I did it correctly.  Calling the $4$ lines $I$, $II$, $III$ and $IV$, I did:  (1) $II \cdot a$  (2) $III \cdot a$  (3) $IV \cdot a$  After this I did:  (4) $II' + I \cdot b$  (5) $III' + I \cdot c$  (6) $IV' + I \cdot d$  So finally I got the following matrix:  $$\begin{pmatrix} a & b & c & d \\ 0 & a^2+b^2 & bc-ad & ac+bd \\ 0 & ad+bc & a^2+c^2 & cd-ab \\ 0 & bd-ac & ab-cd & a^2+d^2 \end{pmatrix}.$$  I thought this would make the determinant a bit easier, unfortunately I must have done something wrong. Is multiplication with single lines allowed as I have done it?  Thank you very much.


Equation and formula, these 2 terms are used alternatively in "Introduction to Linear Algebra 4th edition" without giving a clear definition, so, what is the difference?  Can any one provide some concrete examples like following, to distinguish these 2 terms, especially a case is a formula rather than an equation.     Even a supercomputer doesn't want the inverse matrix: too slow.   Inverses give the simplest formula $x = A^{-1}$ b but not the top speed.   And everyone must know that determinants are even slower-there is no   way a linear algebra course should begin with formulas for the   determinant of an n by n matrix. Those formulas have a place, but not   first place.      The equation Ax = b uses the language of linear combinations right   away.   This question is different to this , which gives a lot of non-math examples without giving a clear comparison between the 2 terms in the context of mathematics.

Sometimes equation and formula are used interchangeably, but I was wondering if there is a difference.  For example, suppose we can calculate a car's fuel efficiency as:  mpg = distance traveled in miles / the fuel used in a gallon   Is that an equation or formula?


I've set up an MS-DOS 6 + Windows 3.1 VM in VMware. Player. It works, but "too well". I want it to run like I remember it. I have set the RAM to 8 MB and the HDD size to match my first 486, but there are no GUI settings for the CPU at all. Nothing like "simulate 486" or anything like that. It goes at super speed. It's not fun and doesn't feel genuine to run it like that. No, I can't use DOSbox. DOSbox is bad software for several reasons, and does some kind of non-MS-DOS approximation instead of actually emulating it. PCem's website doesn't even have an "about" section and I don't trust it whatsoever. Besides, it seems just like DOSbox. After all, I've already set up the VMware VM, and all I want is to make it run slower. There's got to be some kind of configuration file option or something to set this?!

I'm testing an AJAX-heavy web-application. I develop on a new Mac, but I use VmWare Fusion (currently 3.1.2) to test in Windows XP, using  to simulate older versions of IE.  This lets me see how older IE versions would render the site, but I'd also like to see how the site would perform on an older machine. I see in the VM's settings that I can decrease the RAM; is there a way to also dial down the processor speed? How else might I simulate a slow machine?  (I am also going to check out .)


I am wondering what is wrong with my proof showing the real numbers are countable.  Create a set for every real number having 1 digit (10s position) with 0<=x<10 {0, 1, 2, ..., 9} / 10 = {0.0, 0.1, 0.2, 0.3, ..., 0.9} This set covers all numbers with 1 digit, but no number having 2 or more digits  Create a set for every real number having 2 digits (100s position) with 1 digit set and 10<=x<100 {0.0, 0.1, 0.2, ..., 0.9} $\cup$ {10, 20, 30, ..., 90} / 1000 $\cup$ {11, 12, 13, ..., 19, 21, 22, 23, ..., 29, 30, 31, 32, 33, ..., 39, ..., 99} / 100 = {0, 0.01, 0.02, 0.03, ..., 0.09, 0.1, 0.11, 0.12, 0.13, ..., 0.19, 0.2, ..., 0.99} = {0, 0.01, 0.02, 0.02, ..., 0.99} Were the bold number are from the one digit set (I am inserting an element of the one digit set into every 10th position) This set contains all 2 digit numbers, but is missing all sets containing 3 or more digits.  Create a set for every number having 3 digits (1000 position) with the 2 digit set and 100<=x<1000 {0.00, 0.01, 0.02, ..., 0.99} $\cup$ {100, 200, 300, ..., 900} / 100000 $\cup$ {110, 120, 130, ..., 190, 210, 220, 230, ..., 290, ..., 310, 320, 330, ..., 390, 410, ..., 990} / 10000 $\cup$ {101, 102, 103, ..., 109, 111, 112, 113, ..., 119, 121, 122, 123, ..., 129, 131, ..., 999} / 1000 = {0.0, 0.001, 0.002, 0.003, ..., 0.009, 0.01, 0.011, 0.012, ..., 0.019, 0.02, ..., 0.999} = {0, 0.001, 0.002, ..., 0.999} Were the bold number are from the one digit set (I am inserting an element of the two digit set into every 10th position) This set contains all 3 digit numbers, but is missing all sets containing 4 or more digits.   If I repeated this to infinity I would eventually arrive at a set containing all numbers with an infinite amount of digits after the decimal ($0.\overline{00}$ to $0.\overline{99}$). No number  would be missing except for any number with an more digits than infinity, which could easily be gotten by doing one or more rounds. The only problem I can see with this proof is if you defined the natural numbers as having a finite number of digits. However, that would contradict the idea of the natural numbers being  infinite (there are only a finite number of combinations for a set of finite numbers, which is 10^( the number of digits in your limit)), which suggests that at least one natural number has an infinite number of digits. I am very aware of cantors diagonal argument and think this proof shows a counter example. In the case of a real number, like pi mapping to a rational number I would think that since the natural numbers are infinite, I would expect there to be a number that has the exact same digits as pi. If I divide this number by 10^(n-1), were n = number of digits in pi I get pi. Again the only problem with this logic is in how you define the natural numbers. If these is the case then please tell me and point me to a source that defines this. Again I am not a mathematician and have a limited understanding of mathematics, so I am probably wrong here.

I was just thinking about this recently, and I thought of a possible bijection between the natural numbers and the real numbers.  First, take the numbers between zero and one, exclusive.  The following sequence of real numbers is suggested so that we have bijection.    0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.01, 0.02, ... , 0.09, 0.10, 0.11, ... , 0.99, 0.001, 0.002, ... , 0.999, 0.0001, etc.  Obviously, this includes repeats, but this set is countable.  Therefore, the set of all numbers between zero and one is a subset of the above countable set, and is thus countable.  Then we simply extend this to all real numbers and all the whole numbers themselves, and since the real numbers, as demonstrated above, between any two whole numbers is countable, the real numbers are the union of countably many countable sets, and thus the real numbers are countable.    Please help me with this.  I understand the diagonalization argument by Cantor, but I am curious specifically about this proof which I thought of and its strengths and flaws.  Thanks.


This is just a simple problem that I challenged myself to solve: add names to an ArrayList. I think the problem has to do with the while loop I'm using to populate my ArrayList and the Scanner.   I've tried making two separate Scanner objects, but the loop still terminates when it shouldn't.  import java.util.ArrayList; import java.util.Scanner;  public class MyArrayLiat {      public static void main(String[] args) {         // TODO Auto-generated method stub          String finished = "n";         Scanner keyboard = new Scanner(System.in);          ArrayList<String> myArrayList = new ArrayList<String>();          while(finished == "n")         {             System.out.println("Enter data: ");             myArrayList.add(keyboard.nextLine());             System.out.println("Are you finished? y or n");             finished = keyboard.nextLine();          }         System.out.println("myArrayList: " + myArrayList);      }  }   Enter data:  Trevor Are you finished? y or n n myArrayList: [Trevor]   It should keep taking names until I type n, but it terminates after just the first name.

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Today, 2020-10-09 I issued the following command: sudo apt full-upgrade and the system failed to execute the command. The response I got in the command console was: Des:1 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 python3-problem-report all 2.20.11-0ubuntu27.9 [9.704 B] Des:2 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 python3-apport all 2.20.11-0ubuntu27.9 [84,4 kB] Des:3 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 apport all 2.20.11-0ubuntu27.9 [128 kB] Des:4 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 apport-gtk all 2.20.11-0ubuntu27.9 [9.728 B] Err:5 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 bolt amd64 0.8-4ubuntu1   404  Not Found [IP: 71.120.139.139 80] Err:6 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 libfprint-2-2 amd64 1:1.90.2+tod1-0ubuntu1~20.04.2   404  Not Found [IP: 71.120.139.139 80] Err:7 http://mirror.ubuntu.serverforge.org focal/universe amd64 xsel amd64 1.2.0+git9bfc13d.20180109-3   404  Not Found [IP: 71.120.139.139 80] Err:8 http://mirror.ubuntu.serverforge.org focal-updates/main amd64 thermald amd64 1.9.1-1ubuntu0.3   404  Not Found [IP: 71.120.139.139 80] Descargados 232 kB en 2s (98,8 kB/s) E: Fallo al obtener http://mirror.ubuntu.serverforge.org/pool/main/b/bolt/bolt_0.8-4ubuntu1_amd64.deb  404  Not Found [IP: 71.120.139.139 80] E: Fallo al obtener http://mirror.ubuntu.serverforge.org/pool/main/libf/libfprint/libfprint-2-2_1.90.2+tod1-0ubuntu1~20.04.2_amd64.deb  404  Not Found [IP: 71.120.139.139 80] E: Fallo al obtener http://mirror.ubuntu.serverforge.org/pool/universe/x/xsel/xsel_1.2.0+git9bfc13d.20180109-3_amd64.deb  404  Not Found [IP: 71.120.139.139 80] E: Fallo al obtener http://mirror.ubuntu.serverforge.org/pool/main/t/thermald/thermald_1.9.1-1ubuntu0.3_amd64.deb  404  Not Found [IP: 71.120.139.139 80] E: No se pudieron obtener algunos archivos, ¿quizás deba ejecutar «apt-get update» o deba intentarlo de nuevo con --fix-missing? hugo@hugo-MS-7978:~$   I don't know what the problem is, because this is the first time this has happened to me.

After I have performed one of sudo apt-get install eclipse eclipse-cdt g++ procedure I found that Ubuntu is planning to download more than 400Mb and it will take more than 2 hours. It is too long. I also found that it downloads from the US:  Get:21 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main libservlet3.0-java  all 7.0.52-1ubuntu0.3 [294 kB]   I'm in Europe, maybe should I somehow tell Ubuntu to download from a source located closer. How should I do that?


I am running CentOS with cPanel, which creates a custom log directory and writes the logs there. The result is that the IO for the hard disk goes sky high.  If I do lsof I got:  hostsite.com  httpd      2383    nobody 3779w   REG  253,0         0  422463 /usr/local/apache/domlogs/mygamecardotcobnao.super                  hostsite.com-bytes_log httpd      2383    nobody 3780w   REG  253,0      5265  420994 /usr/local/apache/domlogs/myfreefreedatixuua.super                  hostsite.com httpd      2383    nobody 3781w   REG  253,0        36  422464 /usr/local/apache/domlogs/myfreefreedatixuua.super                  hostsite.com-bytes_log httpd      2383    nobody 3782w   REG  253,0      3101  415849 /usr/local/apache/domlogs/myfreedatingfrekeuo.supe                  rhostsite.com httpd      2383    nobody 3783w   REG  253,0        72  422465 /usr/local/apache/domlogs/myfreedatingfrekeuo.supe                  rhostsite.com-bytes_log httpd      2383    nobody 3784w   REG  253,0       672  419338 /usr/local/apache/domlogs/myfreedatingblogsxgo.sup                  erhostsite.com httpd      2383    nobody 3785w   REG  253,0         0  422466 /usr/local/apache/domlogs/myfreedatingblogsxgo.sup      Disabling this domlog is impossible because there are tons of those lines automatically generated.  I just want to point /usr/local/apache/domlogs/ to /dev/null. Can that be done?

I would like to create a "/dev/null" directory (or a "blackhole" directory) such that any files written to it are not really written, but just disappear.   I have an application that writes out large temporary files to a directory. I have no control over the name of the files and I don't really care about the content of these files. I could write a script that periodically clobbers these files, but the files are written out very quickly and fill my disk. I'm looking for something cleverer. I want the application to "think" that it is writing out these files, when in fact, the writes are just being discarded at the other end.  Also see  old related thread.


My son installed Ubuntu on my laptop for me to use I like it except my insulin pump only uses Windows. I know nothing about the structuring of the HD. I have the windows 2000 full installation disk and the Windows vista upgrade disk. I do not have a recovery disk cause my son didn't make one before uninstalling windows and putting Ubuntu on.   I believe it was due to windows crashing that he went to Ubuntu. I am using Ubuntu 12.04.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


How do I make a symbol for the length of a line or vector? I intend the following notation: |AD| is the length of AD. I can't find this symbol anywhere. (When I use shift+backslash in LaTeX, it gives a horizontal line).  For some reason the \cdot also doesn't seem to work, when I write it down like this:  &|AD| \cdot |BD|& = ...   So can anyone please tell me what I am doing wrong?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


2 Measurement Setup Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text 2.1 Radar Equipment Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text 2.1.1 Ultra Wideband Radar Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text M-Sequence Pseudo-Noise Generator Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text Dual-Polarized Vivaldi Antenna Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text 2.1.2 Frequency Modulated Continuous Wave Radar Some text some text some text some text some text some text some text some >text some text some text some text some text some text some text some text >some text some text 2.2 Stepper Motors 2.3 Test Objects  I am not clear on how to create the bold text unnumbered sections and I don't want to have more then 3 Levels

I'm using the report document class for a thesis, and I need to add things like "Acknowledgements" and an "Introduction". I noticed that there is an \abstract command which would have been wonderful if applied similarly. How do I add these without messing up the chapters' numbering while being picked up by the ToC in proper order and page numbering?


i have a question, for example i have a website for example of score results, you can say that is my main website, with scores, news, whathever. But i buy new domains  where is searched a lot on google, if i create in this new domain a 301 redirect to my main website will this have any impact in terms of SEO? Example: Main domain: scoreresults.com  Other domains: scoreresultsintennis.com

Lets say I have a domain already, for example www.automobile4u.com (not mine), with a website fully running and all.  The title of my "Website" says:    <title>Used cars - buy and sell your used cars here</title>   Also, lets say I have fully SEO the website so when people searching for the term buy used cars, I end up on the second or first page.  Now, I want to end up higher, so I go to the google adwords page where you can check how many searches are made on specific terms.  Lets say the term "used cars" has 20 million searches each month.  Here comes the question, could I just go and buy that domain with the search terms adress, in this case www.usedcars.com and make a redirect to my original page, and this way when people search for "used cars", my newly bought domain name comes up redirecting people to my original website (www.automobile4u.com)?  The reason I believe this benefits me is because it seems search engines first of all check website adresses matching the search, so the query "used cars" would automatically bring www.usedcars.com to the first result right?  What are the downsides for this?  I already know about google spiders not liking redirects, but there are many methods of redirecting...  Is this a good idea generally?


fsck /dev/sda1  -->/bin/bash: Output: not found

I am running an HP pavilion dv6000 dual boot win7 and Ubuntu 12.04. (well, up until today).  After a reboot, the boot process drops to the BusyBox shell and I end up at the prompt:  BusyBox v1.18.5 (Ubuntu 1:1.18.5-1ubuntu4) built-in shell (ash) Enter 'help' for a list of built-in commands.  (initramfs)   I've been researching others who have had this same problem, but haven't been able to find any of those solutions to work for me.  I tried the method described , and after the final command   mount -t ntfs-3g /dev/sda1 /root -o force   it does nothing and gives me another (initramfs) prompt.  I can boot to a live CD (USB) and get to a terminal, but it doesn't seem to do much good, as I can see the /dev/sda1 in the ls command, but it doesn't recognize it when I try to cd to it.  One more question: using the command fdisk -l how can I tell which mount point (sda1/sda2) is my windows partition and which one is Ubuntu?


Does .exe setups work? On windows if I need a software I just download it from filehippo and install it but is it the same on Ubuntu.

How can I install applications like Google Chrome on Ubuntu?  Are there any commands to install an application?    Index of answers:


So today when I entered in chromium I got a black screen. I mean, until now every time I entered in chromium the google search bar appeared with my shortcuts to some webpages, but today when I entered I got a black screen and I only can use the upper search bar, but the rest of the screen is just black, this is pretty weird because it''s the first time that has happened to me. Does anyone know why this happens? Help is much appreciated.

I uninstalled some programs yesterday and it is possible I also changed/deleted some files/settings for Chromium browser. When I open new tab in Chromium, I only see blank page - no wallpaper, no shortcuts, no Google search field.  Is there any way to set new tab to this form?  I tried remove all directories for chromium that I found and reinstall it, but problem was not solved: sudo snap remove --purge chromium  sudo find / -name chromium sudo rm -r /etc/chromium sudo rm -r /usr/share/bash-completion/completions/chromium sudo rm -r /root/snap/chromium sudo rm -r ~/snap/chromium  sudo snap install chromium  I also find , but it for Google Chrome, so I do not have this option to use in Chromium. When I install Google Chrome, new tab looks as it should.


In a bash, I have an IP like 104.16.117.182. This is the address of .  But, from the IP, how can I resolve it to the hostname? Like:  >>> magic 104.16.117.182 you get: unix.stackexchange.com   Any idea?

What's the most concise way to resolve a hostname to an IP address in a Bash script? I'm using .


I'm trying to figure out how to get all the left cosets of subgroup $S_{3}$ generated by $(1,2)$. I know what $\langle (1,2) \rangle = \{ (0,0),(1,2) \}$. I'm just not sure how the answer key got $(1,3)\langle(1,2) \rangle = \{ (1,3), (1,2,3) \}$ and $(2,3) \langle (1,2) \rangle = \{ (2,3), (1,3,2) \}$

So I am struggling to understand the definition of a coset. If I have the following symmetric group $S_3=\{1, \sigma, \sigma\tau, \sigma\tau^2, \tau, \tau^2\}$, where $\sigma$=$\left(\begin{array}{ccc}1 & 2 & 3 \\ 1 & 3 & 2\end{array}\right)$ and $\tau$=$\left(\begin{array}{ccc}1 & 2 & 3 \\ 2 & 3 & 1 \end{array}\right)$.  I am given the subgroups $H=${$1,\sigma$} and $K=${$1,\tau,\tau^2$} How would I find all the left cosets of these subgroups? Thanks


I'm tired of ubuntu now and and switching back to windows. Im gonna use the OS-Uninstaller but the problem is I can't boot from my ubuntu cd. When I installed ubuntu im quite sure I pressed F11 to choose boot from cd. Now I tried all F buttons and it just boots normal or gets to a black screen with a bunch of white text and then boots normal.  Here is my motherboard:  Handle 0x0002, DMI type 2, 15 bytes Base Board Information Manufacturer: MSI Product Name: 870A-G46 (MS-7599) Version: 4.0 Serial Number: To be filled by O.E.M. Asset Tag: To Be Filled By O.E.M. Features:     Board is a hosting board     Board is replaceable Location In Chassis: To Be Filled By O.E.M. Chassis Handle: 0x0003 Type: Motherboard Contained Object Handles: 0   Any ideas on how I can boot from cd?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


An invertiable matrix $A_{n\times n}$ is defined as there exists a matrix$B_{n\times n}$ such that $AB=BA=I_{n\times n}$.  Why isn't it defined as there exists a matrix$B_{n\times n}$ such that $AB=I_{n\times n}$? (a weaker condition)  Is it possible that $AB=I,\;BA\neq I$?

If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix.


I am working through  problems in Dummit and Foote and am having a hard time interpreting this question.  Use the generators and relations to shat if if $x$ is any element in $D_{2n}$, which is not of power $r$, then $rx=xr^{-1}$  I thought this relation was already given in presentation of $D_{2n}$. How do I interpret this problem?  $D_{2n}= < r,s | r^n=s^2=1, \hspace{2mm} \underline{rs=sr^{-1} } >$

As a follow-up to , the next two exercises state:       Use the given generators and relations to show that if $x$ is any element of $D_{2n}$ which is not a power of $r$, then:         a) $rx = xr^{-1}$, and      b) $x$ has order 2, and hence $D_{2n}$ is generated by $s$ and $sr$, each with order 2.       Here, $D_{2n}$ has the "usual" presentation  $$D_{2n} = \left\langle r, s \mid r^n = s^2 = 1, rs = sr^{-1} \right\rangle.$$  For part a), since $x$ is not a power of $r$, I have written $ x = sr^k$ for some $0 \leq k \leq n - 1$.  So then $rx = r(sr^k) = (rs)r^k = (sr^{-1})r^k = sr^{k - 1}$, but this doesn't seem to be moving me in the right direction.  Should I be using induction on the power of $r$ in the element $x$ ?  Then for part b), I simply wrote $(sr^k)(sr^k) = s(r^ks)r^k = s(sr^{-k})r^k = s^2 = 1$, but I doubt that I have sufficiently justified my work.  From the comments to the previous question, I get the feeling that this is a very simple verification, but I'm having trouble.  Thanks in advance for your help!


This question is from Victor Shoup's book on number theory chapter 2. The problem statement is as mentioned in the title of the question. I haven't been able to crack this one till now. I focused on solving this using the following information:     If p is an odd prime then $(p-1)! = -1 \pmod p$, otherwise called Wilson's theorem.   When $p \equiv 1 \pmod 4$ then any non square in $Z_p^*$ yields a square root of -1 modulo p.     I think we have to prove here that $b=((p-1)/2)!$ doesn't belong to $(Z_p^*)^2$ but I am unable to use Wilson's theorem or any other result to prove it. PS: Not a homework for me but might be for someone else one day so tagging it as the same.

I need to show that for prime numbers of the form $p=4n+1$, $x=(2n)!$ solves the congruence $x^2 \equiv-1\pmod p$. I then need to show this implies p isn't a gaussian prime.   I have started to solve this using Wilson's theorem that a number $z$ is prime iff $(z-1)!\equiv-1\pmod z$. Therefore the endpoint of my proof should be that $(p-1)!\equiv-1\pmod p$.  As $p$ is of the form $p=4n+1$, I only need to prove that $4n!$ is congruent to $-1$ modulo $p$.   Here is my working so far: Starting with the congruence $x^2 \equiv -1\pmod p$:    $$\eqalign{x^2 = -1\pmod p&\implies   x^2 + 1 = kp \implies (x-i)(x+i) = kp\cr &\implies ((2n)!-i)((2n!)+i))=kp \implies 4n!- 1 =kp\cr}$$   This is where I start to run out of any ideas that seem to get me anywhere. Any tips would be greatly appreciated!


Is there a way to control the power of the Thunderbolt/USB ports on the MacBook Pro (2019), on a port-by-port level? Use case: some dumb equipment draws power from the port (let's say a USB fan). The equipment doesn't have a hardware switch and I want to turn the equipment off without unplugging it. Also, I want to make sure that it gets turned off when the computer goes to sleep or shuts down, so it doesn't consume battery. I know there are simple solutions for most non-Apple hardware, but they don't seem compatible with Apple's special high-tech Thunderbolt ports.

I have a need to turn USB power off (and on) using a script or a piece of software. Ideally it should be possible to turn each port off/on separately, but also turning power off/on from all ports at once is sufficient. The machine I am using is Mac Mini. Anyone has a solution for this?  By USB power I mean Vbus, the 5V/500mA connection. I understand that the data connection is also turned down and it is fine, but it is not enough for me that the data connection is down and Vbus remains powered. This need comes from the need to keep mobile phones constantly connected for automatic testing. Some device/battery combinations do not like to be constantly connected and batteries start swelling in less than a year.  I recognize that multiple variations of this question are around. So far no solution that I could use. I'll list here my findings so far:   it is possible to accomplish this by using external self powered USB HUB and controlling it's power. However, this is not an option for me (even quality hubs have caused other problems in my use). it is possible to disable USB by removing .kext files. Among other sources it is explained in OS X . However this requires reboot and I am not sure if it really disables USB power or just data. there are many claims that it just is not possible. However, OS X itself does it when it detects a device that consumes too much power, so there is at least hardware support. This error message is copied from /System/Library/Extension/IOUSBFamily.kext/Contents/Resources/English.lproj/Localizable.strings: "Unplug the device using too much power to re-enable USB devices." (of course I don't know if the disabling is done by turning off USB power, but I would assume it is natural action for the device that consumes too much of it).  it seems that on macbook the USB ports are normally powered even when the laptop is sleeping. While  is not solving my issue, it is kind of related.   The reason why I need this is that I have a test system where multiple devices are plugged in to a mac mini. The devices also charge over USB. It has turned out that if the device is connected all the time to a charger, it's battery is swollen in about a year, which makes the device unusable, insecure and potentially dangerous. Turning the power off when not needed, would significantly extend devices life.


I'm reading a section in an abstract algebra book, where it reviews vector spaces and suddenly comments that "all vector space have a basis" is equivalent to the axiom of choice...I haven't studied axioms of choice yet and after searching on the internet, I do not see why these two statements are equivalent...Could someone briefly explain to me? Thanks!

I know that the proof that every vector space has a basis uses the Axiom of Choice, or Zorn's Lemma. If we consider an axiom system without the Axiom of Choice, are there vector spaces that provably have no basis?


I have searched far and wide, yet I am confronted in GNOME on 19.04 with the fact that I cannot get umlauts etc to work. I have 2 kali (KDE) machines, on which I can get it to work quite easily. However, in this case, under Settings - devices - typing column - to find the "compose" key - is not there... I've edited etc/default/console-setup to include  XKBOPTIONS="compose:Shift+AltGr" but I am sort of afraid to reboot, in fear that I might break something. Also it does not seem like the correct way since setting this functionality has been standard on previous versions of ubuntu etc.   This question has been asked many times, and has been solved many times, which is how I solved the umlaut problem on Kali/KDE too (since I am quite new on linux). Have tried linux many times in the past but only now it sticks. Any problems I have had up to now I have been able to solve without asking but this one is beyond me.   Am going to reboot now anyway, I guess I will have to.   If I don't return shortly, something broke. Otherwise, I'll be back soon ;-)  Thanks!  returned, system did not break aaannndd.... trying... e  No joy. Pressing the AltGr key just shows the firefox menu bar.  I'm lost.

Now that Unity is gone, the usual way of setting a Compose Key (via Keyboard Preferences > Layout) no longer works (because in Ubuntu 18.04, Devices > Keyboard has no Layout tab).  How do we set a Compose Key in Ubuntu 18.04 Bionic Beaver?


How can i set particle system resolution more 50?  Paticle system must be: emit - volume and grid  Please help!

How can I allow value sliders to be set higher than certain values? For example, I can't slide the subsurf slider past 6. This might seem like a bit of a silly question, but it always bugged me when watching a tutorial or something and somebody said something like      blender can't do more than 6 subdivisions, so add two modifiers   It just seems clunky to add another modifier.  How can I set a value slider such as the subserf setting higher than it normally goes?


I have a lot of strings in which I have to do this. Example: "ABCDEFGH" I want to make it look like this: "AB, CD, EF, GH"

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I would like to know if the word "data" is plural or singular? I have looked up some dictionaries but failed to find any relevant information. Thanks!

Which sentence is correct:     In this section you can make a payment: verify carefully that all the data submitted is correct and confirm by clicking the Proceed button.   or     In this section you can make a payment: verify carefully that all the data submitted are correct and confirm by clicking the Proceed button.


The crash gave me this log:  Completely ignored arguments: [--nativeLauncherVersion, 307] [01:31:10] [Client thread/INFO]: Setting user: kitten245 [01:31:15] [Client thread/INFO]: LWJGL Version: 2.9.4 [01:31:17] [Client thread/INFO]: Reloading ResourceManager: Default [01:31:39] [Sound Library Loader/INFO]: Starting up SoundSystem... [01:31:39] [Thread-5/INFO]: Initializing LWJGL OpenAL [01:31:39] [Thread-5/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org) [01:31:40] [Thread-5/INFO]: OpenAL initialized. [01:31:40] [Sound Library Loader/INFO]: Sound engine started [01:31:44] [Client thread/INFO]: Created: 1024x512 textures-atlas [01:31:55] [Client thread/INFO]: Connecting to mc.hypixel.net, 25565 [01:32:02] [Client thread/INFO]: [CHAT]                                       [01:32:02] [Client thread/INFO]: [CHAT]                           [01:32:02] [Client thread/INFO]: [CHAT] You have 5 unclaimed leveling rewards! [01:32:02] [Client thread/INFO]: [CHAT] §eClick here to view them! # # A fatal error has been detected by the Java Runtime Environment: # #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x000000001c2dc933, pid=3684, tid=6504 # # JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18) # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed oops) # Problematic frame: # C  [ig7icd64.dll+0x6c933] # # Failed to write core dump. Minidumps are not enabled by default on client versions of Windows # # An error report file with more information is saved as: # C:\Users\Sonia\AppData\Roaming\.minecraft\hs_err_pid3684.log # # If you would like to submit a bug report, please visit: #   http://bugreport.sun.com/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # AL lib: (EE) alc_cleanup: 1 device not closed Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release   The Minecraft version I was using was 1.10.

I go to the Minecraft menu and click on singleplayer to test out the 1.9 update. I made a new world (no mods), it said downloading terrain and then it crashes every time (I've tried about 20 times now).  Has anyone else experienced similar issues and know what the fix may be?  Here is the launcher log:  Completely ignored arguments: [--nativeLauncherVersion, 301] [00:35:12] [Client thread/INFO]: Setting user: Teddy_Cromwell [00:35:12] [Client thread/INFO]: (Session ID is <censored>) [00:35:14] [Client thread/INFO]: LWJGL Version: 2.9.4 [00:35:14] [Client thread/WARN]: Removed selected resource pack resources (no region and battle music).zip because it's no longer compatible [00:35:14] [Client thread/INFO]: Reloading ResourceManager: Default [00:35:15] [Sound Library Loader/INFO]: Starting up SoundSystem... [00:35:16] [Thread-5/INFO]: Initializing LWJGL OpenAL [00:35:16] [Thread-5/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org) [00:35:16] [Thread-5/INFO]: OpenAL initialized. [00:35:16] [Sound Library Loader/INFO]: Sound engine started [00:35:18] [Client thread/INFO]: Created: 1024x512 textures-atlas [00:35:26] [Server thread/INFO]: Starting integrated minecraft server version 1.9 [00:35:26] [Server thread/INFO]: Generating keypair [00:35:27] [Server thread/INFO]: Preparing start region for level 0 [00:35:28] [Server thread/INFO]: Preparing spawn area: 5% [00:35:29] [Server thread/INFO]: Preparing spawn area: 8% [00:35:30] [Server thread/INFO]: Preparing spawn area: 15% [00:35:31] [Server thread/INFO]: Preparing spawn area: 21% [00:35:32] [Server thread/INFO]: Preparing spawn area: 27% [00:35:33] [Server thread/INFO]: Preparing spawn area: 34% [00:35:34] [Server thread/INFO]: Preparing spawn area: 42% [00:35:35] [Server thread/INFO]: Preparing spawn area: 48% [00:35:36] [Server thread/INFO]: Preparing spawn area: 56% [00:35:37] [Server thread/INFO]: Preparing spawn area: 66% [00:35:38] [Server thread/INFO]: Preparing spawn area: 74% [00:35:39] [Server thread/INFO]: Preparing spawn area: 81% [00:35:40] [Server thread/INFO]: Preparing spawn area: 91% [00:35:41] [Server thread/INFO]: Preparing spawn area: 98% [00:35:42] [Server thread/INFO]: Teddy_Cromwell[local:E:6d7525a7] logged in with entity id 301 at (244.5, 69.0, 244.5) [00:35:42] [Server thread/INFO]: Teddy_Cromwell joined the game # # A fatal error has been detected by the Java Runtime Environment: # #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007fffcf6e6b37, pid=15456, tid=12424 # # JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18) # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed oops) # Problematic frame: # C  [ig8icd64.dll+0x16b37] # # Failed to write core dump. Minidumps are not enabled by default on client versions of Windows # # An error report file with more information is saved as: # C:\Users\Connor\AppData\Roaming\.minecraft\hs_err_pid15456.log # # If you would like to submit a bug report, please visit: #   http://bugreport.sun.com/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # AL lib: (EE) alc_cleanup: 1 device not closed Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release


I have a Samba share on Win Server (I have no access to the server settings) with many symlinks in it and a PC with Linux (Ubuntu), from which I try to access the share (I mount it via mount.cifs). But when I try to open a folder which appears to be a symlink, I get access denied.  So, here is my question: Is there any way to access these folders without changing samba server settings?

This is Ubuntu server 10.04 64 and samba 3.4.7.  I have a shared directory /home/mit/share and another one /home/temp that I link into the shared one:  ln -s /home/temp /home/mit/share/temp   But on windows, after using internet, I cannot open S:/temp, but on Linux it is possible to access /home/mit/share/temp like expected.   This works if I link directories inside /home/mit/share/temp, so I guess samba is restricting to jump with a link outside/above the shared directory.   EDIT:  See also this question titled .  It seems best to put unix extensions = no into the global section and follow symlinks = yes and wide links = yes only into the shares section, where you really need it.  The unix extension flag has to live in the global section and not in the individual shares sections. But for security reasons it is better to use the other options only where you need it, and not globally.


In an instance where three teams were beaten by 3:1, 4:2 and 5:3, which team qualifies as best losers?

We have played a 7-team competition, all seven teams met, we eliminated the team with the lowest points. After that the remaining six teams played knock out games and the three winning teams will go direct to semi-finals.  We decided that 4 teams should be picked to go for semi-final and that the best loser will join the other three to make it four teams to battle at the semi-final and final.  During the quarter final games, one team is beaten 2-0, another is beaten 3-0 and the third team is beaten in a penalty shoot-out by 4-0.  Now should you want a best loser to join the other three teams making four teams to play in the semi-final, who among these three teams would be in the best losers position.


I'm currently using Ubuntu 20.04.1 LTS. I want to level up my Linux skills so, I want to use terminal as much as possible. Is there a way to work only with terminal and summon a desktop environment only when I need? I'm expecting the system to not be graphical or use GUI unless I want it to. How can I do it? Thanks in advance!

Is it possible to disable X at boot time? I'm setting up a server so it would be nice if it wouldn't load the graphical interface every time I boot.


I have 3 tables that has the same columns name.  The first Table is PriceList1   id      name      price   1.       A         6   2.       B         4   The second is PriceList2   id      name      price   1.       C         3   2.       D         1   The third is PriceList3   id      name      price   1.       E         5   2.       F         6   I want to combine these tables into one table   id      name      price   1.       A         6   2.       B         4   1.       C         3   2.       D         1   1.       E         5   2.       F         6   I use  Select * from PriceList1 p1 left join PriceList2 p2 on p1.id = p2.id join PriceList3 p3 on p3.id = p1.id   And I use left outer join, join, right outer join, right join.  I always got something like this.    id      name      price     id      name      price     id      name      price   1.       A         6        1.       C         3        1.       E         5                                ........

Ok, here is my dilemma I have a database set up with about 5 tables all with the exact same data structure. The data is separated in this manner for localization purposes and to split up a total of about 4.5 million records.  A majority of the time only one table is needed and all is well. However, sometimes data is needed from 2 or more of the tables and it needs to be sorted by a user defined column. This is where I am having problems.  data columns:  id, band_name, song_name, album_name, genre   MySQL statment:  SELECT * from us_music, de_music where `genre` = 'punk'   MySQL spits out this error:  #1052 - Column 'genre' in where clause is ambiguous   Obviously, I am doing this wrong. Anyone care to shed some light on this for me?


After upgrading to Ubuntu 16.04LTS my desktop will not recognize my msi R5450 graphics card.  I used sudo ubuntu-drivers devices to search and it only shows my processor as being the graphics provider. Did I miss something on the install?

I have 14.04.5/16.04 or newer and an AMD GPU. I'm not getting the performance I want, and some programs say they need things like OpenCL.  I've heard about fglrx, but if I try to install it on my machine, it breaks and I have no GUI.  Is there anything I can do to get my AMD card working to its full potential?


To delete directories you need to use the command rmdir instead of rm. I learned that unix sees everything as a file. So what is the reason that rm can't delete any type of file?

I use BSD and Linux every day, I have never had a circumstance which I must use rmdir(1) rather than rm(1). What's the purpose of rmdir's existence?


Since my phone been stolen..I already blocked my phone..so the new SIM card resend back..when I install at new phone.i find out my what app still been use...so what should I do now?

I lost my Android phone, but my WhatsApp is still on. How I can stop someone who is using it?  I don't have the SIM with me. The people who found it is using my WhatsApp account. When they went online, I tried to talk but they did no reply.


I am currently writing papers on the immigration pattern in the US throughout history. I came across a problem that I have never been taught before (I am a ESL speaker) about the plurality of the people of a certain nation.  Would the plural of the people German nationality "the Germans" or "the German"? Is the "s" necessary to turn it into a plural noun? I have this question because I know that the plural of the people of Chinese nationality is "the Chinese" but not "the Chineses."  Is there any rule to this? If so, what would be the plural form for the people of Irish nationality or Indian nationality?

I always have doubts whether to use a singular or a plural noun when I refer to certain peoples.  For example, we say Americans, Italians, Brazilians, Russians and Austrians.  But we say The British, The English, The Portuguese, The French, The Spanish, The Chinese, and The Irish. When it comes to those nationals I rarely hear of, I'm never sure. These would include people from countries such as Azerbaijan, Armenia or Kenya. Is there any rule as to whether we should use singular or plural ?


While browsing sources of LinCAN driver, I found some macros that baffled me.  #else /*CONFIG_PREEMPT*/ #define can_preempt_disable()      do { } while (0) #define can_preempt_enable()       do { } while (0) #endif /*CONFIG_PREEMPT*/   I understand the usefulness of   do {    ...;   if(condition) break;   ...  } while (0);    using break as a kind of throw. I semi-understand wrapping a sequence of functions like   #define FOO() do { foo(); bar(); } while (0)   to avoid caveats with braceless if. I understand sometimes "no-op statements" are required for a #define. But why this particular kind? specifically, empty braces, false condition, do...while? Some syntax caveats I can't quite grasp?

In many C/C++ macros I'm seeing the code of the macro wrapped in what seems like a meaningless do while loop.  Here are examples.  #define FOO(X) do { f(X); g(X); } while (0) #define FOO(X) if (1) { f(X); g(X); } else   I can't see what the do while is doing.  Why not just write this without it?  #define FOO(X) f(X); g(X)


So when I was younger I got a series of books involving an astronomer with Kung fu abilities who discovers a rogue object orbiting Jupiter. Next, he and his team figure out that it has left Jupiter's orbit and is on a course to intercept Earth. In there somewhere is some Russian espionage, the astronomer seduces his intern, and then by the end of the first book the plan is to send the astronomer into orbit to check out the alien spaceship that is now orbiting Earth (I believe the spacecraft was specifically egg shaped and golden). He gets inside and everyone thinks that he dies when he runs out of oxygen, but there were three books I believe and in the second one they recover his body and it turns out that somehow he got self-replicating nanobots into his bloodstream that continuously repair his organs, to the point where he no longer needs to eat or sleep. It's been some time since I read this series, but I'd like to reread them if only I could remember what they were called or even just the author's name.

Upon realizing it is a sarcophagus, he decides to sacrifice himself (I think by disconnecting his air) and exist in it for eternity along with the original creature. It may have been in an old Omni magazine, or some other periodical. I thought it may have been in the anthology "Dead Astronauts" but I did not find the story in there.


I'm working with Swish++ in Ubuntu 12.04. Due to my thesis I must install Swish++ from the source code. During the installation I faced with several problems, but finally I solved them and Swish++ package was successfully installed. Although I found a discrepancy with Swish++ names (I asked  but got no answers there). Anyway, despite this, everything went ok. I could use index and search with all the functions of index++ and search++. But now I have another problem. I changed config files of Swish++ and need to recompile it. The first time I did it I used command make. How can I delete Swish++ and install it again? The command sudo apt-get remove --auto-remove swish++ says that package hasn't been istalled and can't be removed. How can I remove programms having been installed from the source code?

I used source code to build one package such as below:  ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --libexecdir=/usr/lib --with-package-name="Myplugin" --with-package-origin="http://www.ubuntu.org/" --enable-gtk-doc --disable-static make make install   But unfortunately, i discovered that its the latest version, and has lot of bugs, so i need to remove it/uninstall it. But how can i do so? I tried make clean; make uninstall but still i see it exist:  # pkg-config --list-all | grep Myplugin myplugin-.... $ ls /usr/lib/myplugin/libXYZ.so exist....   How do you remove this now?


I have before the beginning of the document \addbibresource{references.bib} and at the end of it \printbibliography.   The references have this format :   @ARTICLE{2015MNRAS.452.1089P,    author = {{Porth}, O. and {Komissarov}, S.~S.},     title = "{Causality and stability of cosmic jets}",   journal = {\mnras}, archivePrefix = "arXiv",    eprint = {1408.3318},  primaryClass = "astro-ph.HE",  keywords = {instabilities, MHD, relativistic processes, stars: jets, galaxies: active, galaxies: jets},      year = 2015,     month = sep,    volume = 452,     pages = {1089-1104},       doi = {10.1093/mnras/stv1295},    adsurl = {http://adsabs.harvard.edu/abs/2015MNRAS.452.1089P},   adsnote = {Provided by the SAO/NASA Astrophysics Data System}   No error, but doesn't print a thing.  \documentclass[12pt,twoside]{report}  \usepackage[utf8]{inputenc}  \usepackage[english,greek]{babel}   \usepackage[a4paper,width=160mm,top=25mm,bottom=25mm,bindingoffset=6mm] {geometry}  \usepackage{amsmath}  \usepackage{esint}  \usepackage[normalem]{ulem}   \usepackage{graphicx}  \usepackage{subcaption}  \graphicspath{{Images/}}  \usepackage{array}  \usepackage{wrapfig}  \usepackage{multirow}  \usepackage{tabu}  \usepackage{wrapfig}  \usepackage{hyperref}  \usepackage{fancyhdr}  \newcommand{\uvec}[1]{\boldsymbol{\hat{\textbf{#1}}}}    \pagestyle{fancy}  \fancyhead{}  \fancyhead[RO,LE]{Αλληλεπίδραση αστροφυσικών πιδάκων πλάσματος με το περιβάλλον  τους} \fancyfoot{}  \fancyfoot[LE,RO]{\thepage}  \fancyfoot[LO,CE]{Κεφάλαιο \thechapter}  \renewcommand{\headrulewidth}{0.4pt}  \renewcommand{\footrulewidth}{0.4pt}    \usepackage[style=authoryear,sorting=none]{biblatex}  \addbibresource{references.bib}    \title{Αλληλεπίδραση πιδάκων με το περιβάλλον τους}  \date{Oκτώβριος 2017}     \begin{document}  "  End: "   \nocite{*}  \printbibliography  \end{document}

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


Is there any intuitive explanation for: $$e^{i\pi} + 1 = 0$$  About whether this question is a duplicate, what is asked for is not a proof but an explanation that helps with the not-so-intuitive aspects of the identity.

Could you provide a proof of Euler's formula: $e^{i\varphi}=\cos(\varphi) +i\sin(\varphi)$?


How to find $m$ if $(x^2 + x + 1) | ((x + 1)^m - x^m - 1)$ I tryed to use eyler theorem, but nothing happens. Sorry for bad english.

I have to find the form of n i.e. whether n is even or odd and whether it is multiple of 2 or 3 such that:  $x^2 + x + 1$ is a factor of $(x+1)^n - x^n - 1$  What I tried:  $$x^2 + x + 1 = (x + 1)^2 - x $$  also,  $$(x+1)^n-x^n-1= \binom{n}{o}x^n + \binom{n}{1}x^{n-1} + ... + \binom{n}{n-1}x + \binom{n}{n}.1 - x^n - 1$$  $$=\binom{n}{1}x^{n-1} + ... + \binom{n}{n-1}x$$  after getting this far I tried with taking x and n common but still couldn't able to find the right direction.  I need extra hints to solve this.


The Harry Potter series discusses many spells created by particular wizards like Snape and Voldemort. What does it really mean to create a spell?   Does the creator select a befitting Latin phrase and certain wand movements to channel the magic inherent in him? More importantly, how does he/she seal these for use by all future wizards?  The first may be all right, since it seems suggested in the series that, in principle (i.e., with sufficient ability, expertise in channelling magic etc.), any spell could work non-verbal and wandless. It is the second subquestion above that demands an answer.  After all, every spell discussed had to be created at some point in the past, since Latin had a beginning in history.

In the Harry Potter series, are wizards capable of creating their own spells, or are they limited to the spells that they're taught/learn?  I seem to remember something about Snape creating sectumsempra, but I'm not sure if that really is the case.


Attempting to install MythTV on Ubuntu 18.04, I ran...  sudo usermod -a -G mythtv roger   ...and logged out and back in. This . But: my group memberships didn't change.  I had to reboot. Why?

In ubuntu 18.04 with default desktop, behaviour of logout/login has changed:  Previously on an Ubuntu system, when I find that I need to add my user id to some group, it was sufficient to   sudo adduser ludwig docker # adds me to group docker   and then I had to logout and login again to make the group change effective.  I notice that with Ubuntu 18.04, after adding the group and logging out and back in, the list of effective groups is still unchanged.  As a workaround I rebooted the system, which is inconvenient (requires making the right selection in grub and re-entering the disk encryption password).   Why is the behaviour now like this?  Can I do something else short of rebooting?   (I know I can ssh into localhost and get the correct groups in the ssh session only. This is also too inconvenient.)


Let $S$, $T$ be linear operators on a finite-dimensional vector space $V$ over $\mathbb{C}$. Suppose $$S^2 = T^2 = I.$$ Show that there exists either a $1$-dimensional or $2$-dimensional subspace of $V$ which is  invariant under $S$ and $T$.  Ok so, since $S^2 = T^2 = I$,  either $1$ or $-1$ are Eigenvalues of S and T. i,e  The Minimal Polynomial $M_T$ and $M_S$ satisfy $$M_T \; | \;  (x+1)(x-1)$$ $$M_S \; | \;  (x+1)(x-1)$$ Edit : Found the same question elsewhere. For those of you who are interested in the answers.

I'd love some help with this practice qualifier problem:  If $A$ and $B$ are two linear operators on a finite dimensional complex vector space $V$ such that $A^2=B^2=I$ then show that $V$ has a one or two dimensional subspace invariant under $A$ and $B$.    Thanks!


Lets suppose I have a listener for a Button  public class Visualizer1 implements ActionListener {         public void actionPerformed(ActionEvent a) {             try {                 Runtime rt2 = Runtime.getRuntime();                 Process p = rt2.exec("visualizer/vis1.exe");                 InputStream in = p.getInputStream();                 OutputStream out = p.getOutputStream();                 InputStream err = p.getErrorStream();                  p.destroy();             } catch (Exception exc) {/* handle exception */             }   the "vis1.exe" will execute without any problem and it will open up but if I have an application with a ".bat" extension like if it was(vis1.bat), it won't open up.  Note: .bat extension is an executable file

In my Java application, I want to run a batch file that calls "scons -Q implicit-deps-changed build\file_load_type export\file_load_type"  It seems that I can't even get my batch file to execute. I'm out of ideas.   This is what I have in Java:  Runtime.    getRuntime().    exec("build.bat", null, new File("."));   Previously, I had a Python Sconscript file that I wanted to run but since that didn't work I decided I would call the script via a batch file but that method has not been successful as of yet.


I have just installed Ubuntu 18.04 and now I want to create a partition in my hard drive. But I have only one partition and I found in a video that one cannot create partition which is being used. I am unable to create partition. What should I do?

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I am using the \usepackage[shortlabels]{enumitem} package for automatic enumeration of question in my LaTeX document. However, I would like sometimes to mark (a) question(s) with an asterisk as to declare its level of difficulty. How can I do that?  I certainly don't like doing it manually , e.g after the \item command to place an asterisk like so \item $*$. Also I would like the asterisk to be a superscript to the number e.g something like 5* suppose.   Sample:  1. This is a sample question. 2. This is another sample question. 3*. This is a sample question with some difficulty.   This is what I would like the output to be. However the dot. I would like to be aligned with the other dots, if that , is of course possible.   Can this be done?

In an enumerate environment, I want a few (not all) of the items to have asterisks which appear before the number (I don't feel strongly about whether the number or the asterisk is horizontally aligned with the other numbers).  Is there a less crufty way to do this than, say, using multiple lists (or — horrors — numbering manually)?  I'm already using enumitem for an unrelated purpose, if that helps, although I didn't find a solution after a quick skim of its manual.


Find the limit of the sequence $(b_n)_{n=1}^{\infty}$ defined by  $$b_{n} = \sum_{k=1}^{n} \frac{n}{n^2+k} = \frac{n}{n^2+1} + \ldots +\frac{n}{n^2+n} $$  for $n \geq 1$. I know that I have to use Squeezing Principle but I do not know how to find the lower and upper bound

Please help me solve this. Please try to give some details also.  Let $a_n=\sum_{k=1}^n  \frac{n}{n^2+k}\ $for $ n \in\mathbb{N}$ then the sequence $\{a_n\}$ is (choose the correct option):     Convergent   Bounded but not convergent   Diverges to infinity   Neither bounded nor diverges to infinity     My thoughts : I tried doing it by testing if it is monotonic with help of $a_{n+1} -a_n$ and checking if its +ve or -ve but, the the terms dont simplyfy by cancelling each other...


We are Indian citizens and are planning to travel by Egypt air from Mumbai to Toronto via Cairo. The layover is 14 hours in Cairo.  As per Egyptian Embassy, transit without visa is applicable if the layover is upto 12 hours.  do we actually need a transit visa for a layover of 14 hours?

We are Indian passport holders, with valid visas for Canada. Plan is to take the EgyptAir flight Mumbai to Toronto, via Cairo. Problem is Egypt embassy website says we don't need Transit Visa if transit is up to 12 hours but here transit is 14 hours.    Has anyone with a Indian passport traveled this route? What was your experience at Cairo? Did you need a transit visa?


The difference between the number of answers and a question with an accepted answer should be clearer on MSO.     MSO vs Cooking.SE  Edit This could be an issue for Daltonics. In my case, I have the brightness of the monitor down to reduce fatigue and the yellow doesn't come out so bright. There are a number of ways to address this. 1. Remove the square from the non-accepted answers 2. Make the square of the accepted answers another form (a star!) 3. Make the square of the accepted answer greener (and remove the yellow letters for contrast). 4. etc.  Edit The real issue (if there is one) is that the difference is one-dimensional, while it should be multi-dimensional. .          Avoid absolute judgment limits. Do not ask the user to determine the level of a variable on the basis of a single sensory variable (e.g. color, size, loudness). These sensory variables can contain many possible levels.

Related to these questions:    When viewing the Meta user profile, the difference between questions with accepted answers and questions without is pretty subtle. At first glance, I couldn't tell the difference at all. Can the contrast between the styles be increased a bit to make it easier to see?     This screenshot doesn't look too bad, but when looking at a list going down a whole page, it gets a bit difficult to pick one out at a glance. (I'm guessing even more so for some of the color-challenged users)


I have a pair of batteries that can operate at 7.2V (series) or 3.6V (parallel) and I need to power up a device using 5V.  I can use a Voltage Regulator to down voltage at 5V or I can use maybe transistors to up voltage at 5V. Which is more efficient?, what would you recommend for power up that circuit?

I have a  that converts 4.2V  (two 4.2V cells in parallel) to 5V. Another option is to use a  from 8.4V (two 4.2V cells in series) to 5V. Considering both cited circuits are well implemented, which choice would be more efficient in terms of power dissipation?  I am looking for some general rule as "step-down is always preferable than step-up" or "the absolute voltage difference matters" etc.


I am confused about using 'being' in the middle of the sentences. For example I saw in an article in which 'being' was used like this:     However, the evidence points to placebo effects being more important than any neuro-pharmacological ones.   In that sentence why 'to be' was not used? What is the gramer rule used there? Is this a special structure?   Another sentence:     ...... and we feel that incorporating them can help to broaden the scope of questions being examined.   In this sentence, 'being examined' seems to be reduction of relative clause, if so, why not used just 'questions examined'.  Any response would be appreciated.

I have a problem analysing this sentence from the point of finite/nonfinite clauses, clause elements and their functions:     He does not want to destroy his parents' dream of him achieving a Cambridge degree.   I am especially interested in the: dream of him achieving a Cambridge degree.  I know that 'achieving a Cambridge degree' is a non-finite -ing participle clause. However what is its function? And what is the function of 'of him'? Is it a postmodification?


For a positive integer $n$  let $f_n(x)=x^{n-1} +x^{n-2}+.....+x+1$  then what can we say about $\displaystyle f_p(x^{p^{c-1}})$ For every prime $p$ and every positive integer $c$ , is it reducible or irreducible over $\mathbb{Q}[x]$. Solution i tried - I know that for $f_p(x)=x^{p-1}+x^{p-2}+....+x+1 $ is a cyclotomic polynomial and irreducible over $\mathbb{Q}[x]$ but how can i use this to show that $\displaystyle f_p(x^{p^{c-1}})$  is reducible or irreducible over $\mathbb{Q}[x]$ ? please help Thank you

Show that   $f_p (x^{p^{e-1}})$ is irreducible over $\mathbb{Q}$. I know it is obviously true for $ p=2$. Please suggest me any hints


has some interesting links under Related questions: the links don't have titles.    A little investigation shows that's not surprising; they link to answers instead of questions, and those don't have titles:

On two three of the four newest Meta questions, there are posts in the "related" section without a title:    I was curious to see what that was, and the link was a link to an answer. Clicking the link took me to the answer, and the score in the link was the score of the answer, not of the question (in the example above, the answer had score 8 and the question had score 3).  What's also strange is that although it was a link to an answer, it had a question URL (in the example above ).  I saw this happen just recently on several questions on both Meta Stack Exchange and Super User, and I have never seen this happen before. I'm quite sure this is a bug.


It's a bit confusing due to the nature of thinking. If I was thinking something and it turned out to be false: I have been thinking that I'm getting sufficient sleep, but it turns out I wasn't. Or should it be had since I just thought that I'm not getting sufficient sleep? I had been thinking that I was getting sufficient sleep, but it turns out I wasn't. What if I realized a few hours before the conversation that I wasn't getting sufficient sleep? I feel that "I have been thinking a lot, so my head hurts" is better off with have been. Also, "I have/had been thinking of calling you" seems to be fine with both. If we take a different example, I think if you were running for a few hours and are now walking, should you say I have been running..? But if you were doing sprints everyday and decided to jog today, I had been doing sprints... is better?

Please anyone tell me when we have to use "has been, have been , had been" and something  started in past and still continuing is it possible to use has been ?


I want to put figure in the document so that it is positioned in the center but its margin goes beyond linewidth. For that I am using the following command.   \documentclass[a4paper]{article}  \usepackage{graphicx}  \begin{document}  \begin{figure} \centering \includegraphics[width=1.3\linewidth]{norm.png} \caption{A Normal Dist} \label{fig: borm}  \end{figure}  \end{document}   The picture that I am using is attached to this post and can be seen below.     If I put the code in this way:  \documentclass[a4paper]{article}  \usepackage{graphicx}  \begin{document}  \begin{figure} \centering \includegraphics[width=\linewidth]{norm.png} \caption{A Normal Dist} \label{fig: borm}  \end{figure}  \end{document}   Then the picture is set to the center nicely, but i want it to extend over the linewidth both to the left and to the right equally. If I use the code I copied previously then the picture extend indeed, but it extends only to the right not to the left.   Can anybody help me fix the issue.   I have read documentation for graphics, graphicx but i could not find it out there.

I have a figure that is wider than the \textwidth of my document. (I don't want to change the \textwidth.) As a result, the leftmost part of the figure is flush with the left margin, while the rightmost part spills into the right margin too much. I'd like to center the figure, so that it will exceed the \textwidth equally on both sides.


The drones are able to adapt to energy weapons, but what about kinetic weapons like bullets or rail guns?

In "First Contact" Picard kills a couple of Borg drones in the Holodeck with a holographic Tommy gun.  It would appear that while the Borg are able to adapt to become impervious to energy weapons, they are vulnerable to bullets.  This looks like a gaping logical hole: why couldn't Star Fleet replicate "primitive" assault rifles to fight the Borg, if they knew that phasers were useless against them?  Has this ever been addressed?