I just purchased a Microsoft Surface Go. It comes in "S-Mode" which means I can't install anything on it without going through the Microsoft Store. Now I am trying to install a software and I can't because it requires Windows 10 version 18362.0 or higher and I am in version 17763.914. I ran Windows Update twice and restarted the device but it didn't upgraded the Windows build number.  Are there any way to upgrade to the latest build of Windows in S Mode or am I stuck to wait and hope Microsoft pushes me an update one day ?

Please let me know how to disable Windows 10 Home in S Mode?  Already I followed following steps: Microsoft Store App > In the app, search for "switch out of s mode"  On the Switch out of S mode, selected Get button but it says unable to upgrade Try again.  Let me know, how to disable Windows 10 Home in S Mode?  Regards John


I'm tying to add custom right click context menu with jQuery on (.message) element what will be available after foreach loop.  In my index html file i have div by id (show_case) chat.php    foreach ($messages as $key => $value) { ?>

<?php echo $value['username']; ?>
 say:
 <?php echo $value['message']; ?>

 <?php }     }   chat.js used jQuery/ajax  chat.fetchMessages = function () {      var data = {method: "fetch"}     $.ajax({         url: 'ajax/chat.php',         type: 'POST',         data: data,         success: function (data) {             $('#show_case').html(data);         }      }); }   Now I want to select div with class message in foreach loop to handle my context menu options menu.js  $('document').ready(function() {     $(".message").on("contextmenu", function (e) {          e.preventDefault();         var menu = $(".menu");         menu.hide();         //let get xposiion;         var xpos = e.pageX;         var ypos = e.pageY;          menu.css({             top: ypos,             left: xpos         });                 menu.show(200);   I can't select it but it doesn't work. What should I do?

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I am writing my thesis and the font size of the chapter title is defined in the class of the document. Somehow I cannot make bigger than \fontsize{60}{70}. Even if I write \fontsize{3000}{70} I cannot observe any difference.  Is there a way to change it?  Thanks  My code (in the class file):   % Numbered chapter heading style: \renewcommand{\@makechapterhead}[1]{%   {\singlespacing     \parindent \z@ \raggedleft \normalfont      \vspace*{5mm}%       \ifnum \c@secnumdepth >\m@ne     \usepackage{lmodern} \usepackage{graphicx}     \fontsize{120}{60} \selectfont \scshape \bf \textsc \space \thechapter         % Chapter followed by number     \par\nobreak     \fi     \interlinepenalty\@M     \vspace{20mm}%       \huge \scshape \bf #1\par                                                            % chapter title     \rule{\textwidth}{1pt}                                                                                %horizontontal line                          \nobreak    \vskip 40\p@   }}

I may be wrong, but it seems to me that I cannot obtain non-integer (or non-preloaded) font sizes (say, 9.876pt) using \fontsize.  If this is true, how do I do this in LaTeX?  Do I have to resort to the \font ... at ... primitive?  (The reason I need this is that I'd like to implement a more LaTeXy way to do the \diminuendo macro from .)


Stuck running Ubuntu 16.04 LTS on a Lenova desktop with a small boot partition now with 0(zero) bytes after many upgrades. Currently at 4.4.0-71-generic but new upgrades fail. Have tried suggestions from many "solutions" but still can not upgrade.  None of the following free-up space:  sudo apt-get clean  sudo apt autoremove --purge  sudo apt-get autoremove --purge  sudo purge-old-kernels  sudo apt autoremove  sudo apt-get purge linux-image-4.4.0-67   Have also purged all the other old linux-images that do not have dependencies.  Any new suggestions?

My /boot partition is nearly full and I get a warning every time I reboot my system. I already deleted old kernel packages (linux-headers...), actually I did that to install a newer kernel version that came with the automatic updates.  After installing that new version, the partition is nearly full again. So what else can I delete? Are there some other files associated to the old kernel images?  Here is a list of files that are on my /boot partition:  :~$ ls /boot/ abi-2.6.31-21-generic         lost+found abi-2.6.32-25-generic         memtest86+.bin abi-2.6.38-10-generic         memtest86+_multiboot.bin abi-2.6.38-11-generic         System.map-2.6.31-21-generic abi-2.6.38-12-generic         System.map-2.6.32-25-generic abi-2.6.38-8-generic          System.map-2.6.38-10-generic abi-3.0.0-12-generic          System.map-2.6.38-11-generic abi-3.0.0-13-generic          System.map-2.6.38-12-generic abi-3.0.0-14-generic          System.map-2.6.38-8-generic boot                          System.map-3.0.0-12-generic config-2.6.31-21-generic      System.map-3.0.0-13-generic config-2.6.32-25-generic      System.map-3.0.0-14-generic config-2.6.38-10-generic      vmcoreinfo-2.6.31-21-generic config-2.6.38-11-generic      vmcoreinfo-2.6.32-25-generic config-2.6.38-12-generic      vmcoreinfo-2.6.38-10-generic config-2.6.38-8-generic       vmcoreinfo-2.6.38-11-generic config-3.0.0-12-generic       vmcoreinfo-2.6.38-12-generic config-3.0.0-13-generic       vmcoreinfo-2.6.38-8-generic config-3.0.0-14-generic       vmcoreinfo-3.0.0-12-generic extlinux                      vmcoreinfo-3.0.0-13-generic grub                          vmcoreinfo-3.0.0-14-generic initrd.img-2.6.31-21-generic  vmlinuz-2.6.31-21-generic initrd.img-2.6.32-25-generic  vmlinuz-2.6.32-25-generic initrd.img-2.6.38-10-generic  vmlinuz-2.6.38-10-generic initrd.img-2.6.38-11-generic  vmlinuz-2.6.38-11-generic initrd.img-2.6.38-12-generic  vmlinuz-2.6.38-12-generic initrd.img-2.6.38-8-generic   vmlinuz-2.6.38-8-generic initrd.img-3.0.0-12-generic   vmlinuz-3.0.0-12-generic initrd.img-3.0.0-13-generic   vmlinuz-3.0.0-13-generic initrd.img-3.0.0-14-generic   vmlinuz-3.0.0-14-generic   Currently, I'm using the 3.0.0-14-generic kernel.


How do I prove the following inequality :  $$\Bigg(\frac{2}{\alpha^2} \, \big( e^{\alpha x} - e^{\alpha y} \big) \, + \, e^{\alpha y} (y^2 - x^2) \; \Bigg) \geq 0 $$  given, $x, y \geq 0$ ?  Can anyone provide me with hints about this problem ?  Here, $\alpha$ is a strictly positive constant.

How do I prove the following inequality :  $$\Bigg(\frac{2}{\alpha^2} \, \big( e^{\alpha x} - e^{\alpha y} \big) \, + \, e^{\alpha y} (y^2 - x^2) \; \Bigg) > 0 $$  given, $x, y > 0$ ?  Can anyone provide me with hints about this problem ?  Thanks in advance.  Here, $\alpha$ is a positive constant.


I tried to install in VirtualBox (ver. 6.1.6) Ubuntu Desktop 18.4 Desktop and 16.04 Destktop from full images and also mini, but it still fails.   I set different path do store virtual drive and configuration files.  I tried to change settings in settigns of virtual machines:   changing video memory size Enabling and disabling Acceleration  different numebr of cores different types of virtual drives (VDI, VHD, dynamically allocated, or not) Acceleration interface (none, legacy, hyper-V, etc),  turning on and off Hardware Virtualization changing Motherboard's Chipset PIIX3 and ICH9   but still I have problems.  In most cases it was, that during starting i got message:  [   0.075766] Spectre V2: Spectre mitigation: LFENCE not serializing, switching to generic retpoline   but it seems, that instalation go furher and GUI instalator runs, but during loading GUI instalator, for one short moment I got additional message:  [   8.948746]  [drm:vmq_host_log  [vmwgfx]] *ERROR* failed to send log [   8.951199]  [drm:vmq_host_log  [vmwgfx]] *ERROR* failed to send log   In this case it is still running, and even that I can provide all the necessary information for installation like Time zone, name, pasword. But after that i got final maessage:    I was installing from ISO file downloaded from official Ubuntu site. I thought, that maybe there were error during download and ISO file was corrupted, but I did it a few times, and result was the same. Even I tried to install from minimal version of installer and download everything needed during installation.   Using other configugarion (which I cannot replicate now), instalation was stacking in GUI intstalator, and needed very much time to go further the initial setup.  Has anyone similar problem? Does anyone have any idea, what's wrong?  Best regards, Marcin  PS  I have HP EliteBook 745 G6, 16GB RAM, 256 GB SSD, Windows 10 1903, Virtualbox 6.1.6

Today I downloaded Ubuntu for my laptop. It runs great from a bootable USB, but when I tried to install it, I got the following error message: The installer encountered an error copying files to the hard disk:  [Errno 5] Input/output error  This is often due to a faulty CD/DVD disk or drive, or a faulty hard    disk. It may help to clean the CD/DVD, to burn the CD/DVD at a lower   speed, to clean the CD/DVD drive lens (cleaning kits are often    available from electronics suppliers), to check whether the hard disk   is old and in need of replacement, or to move the system to a cooler   environment.     I tried everything to install it on my laptop including redownloading the Ubuntu ISO image, but nothing worked.


I know how to change the color of the document but is there a way to make it a picture instead of a color?

How do I create an image behind text in Google docs (the text editor part)?


I really like the new way that macos tiles windows, but what I don't like is that it always puts the windows in a new Space. So I end up having to navigate to the new space, while the original is left doing nothing. Is there a way that I can tile windows (i.e. holding down the green window button and selecting "tile left") without it automatically moving it to a new Space? It's such a weird implementation. On Windows 10, you can easily do it by just dragging to the sides.

Currently, if I want to tile two instances, I press the green button on the top-left and place the instance accordingly. However, each of the tiled instances always go into full screen mode. For a chrome instance, this is annoying as it means it's not possible to see the tabs. How do I tile windows without making them go  full screen?


I can find a lot of information on the opposite (removing Ubuntu from a dual boot) but not how to remove Windows from a dual boot. I did this once before and then I just deleted the whole EFI partition, however, that was a bad decision (also couldn't boot Ubuntu because it was installed in UEFI mode) and in the end I had to do a clean install.  So what I did now is removing the NTFS partition and keep the EFI partition intact. However the Windows Boot Manager still shows up in GRUB, but of course gives an error when selected.  So I thought an update-grub might solve it, but it says:  Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.4.0-24-generic Found initrd image: /boot/initrd.img-4.4.0-24-generic Found linux image: /boot/vmlinuz-4.4.0-22-generic Found initrd image: /boot/initrd.img-4.4.0-22-generic Found linux image: /boot/vmlinuz-4.4.0-21-generic Found initrd image: /boot/initrd.img-4.4.0-21-generic Found Windows Boot Manager on /dev/sda2@/EFI/Microsoft/Boot/bootmgfw.efi Adding boot menu entry for EFI firmware configuration done   So how do I get rid of this Windows Boot Manager entry in EFI? I tried to use efibootmgr as suggested by  but update-grub keeps picking it up and when I reboot and run efibootmgr again the entry is back...

See this   I have this on my Lenovo s205 too.   Is there some way to remove "ubuntu" from the menu? I don't even have it installed anymore.


If schadenfreude means "pleasure derived by someone from another person's misfortune", is there a word to call someone who can't feel happy when something good/exciting happens to a relative/friend/someone close?

Schadenfreude is the joy or pleasure derived from the misfortunes of others. What is the word for joy or pleasure derived from the happiness of others?


An electron can be moved using magnetic field so how about neutron? What really happens at quantum level when you physically move it and what fundamental force is involved? For this question let's ignore gravitational force thanks.

I know that neutrons are neutral and have no charge, but is there any other way to interact with them?


Yesterday a question of mine on EL&U, , which had been closed as a duplicate,  was deleted automatically by the system.      deleted by Community♦ 10 hours ago (RemoveDeadQuestions)   The weird thing is, the post had been edited because I wanted to reopen it. As no answers had been posted, no answers were at risk of invalidation. I decided to broaden the scope of the question and for the sake of clarity, the title was changed. I also clearly defined where the original post ended and where the new edit began. Unfortunately, the question wasn't reopened, and it earned a further downvote. The score currently stands at -1 (+3 and -4)  I was prepared to edit it further because I rather liked the question, and thought it deserved a second chance but now I have to wait for three users on EL&U to cast their votes to undelete it. Well that's never going to happen, mainly because no answers were posted and the (popularity) score is low.   The  about deleted posts, states        The system will automatically delete closed, unlocked questions with zero or negative score having no positively scored or accepted answers or pending reopen votes, that were closed for any reason other than duplicate nine or more days ago and haven't been edited in the past nine days.       EDIT      It's been brought to my attention that the relevant FAQ entry that concerns my case is #9. The system is also known as the         The system will automatically delete negatively-scored, unlocked, and unanswered questions that are older than 30 days. (RemoveDeadQuestions)      First and foremost, my question was 14 months old. Second, it was closed during the entire period, so it would have been impossible for anyone to have posted an answer. Third, there is no mention above that these include closed or duplicate questions. I had always been under the impression that duplicate questions were exempt from deletion. I now know they're not, unless one or more answers have been posted or if the question has a positive score.     UPDATE (June 2019) Just to make it clear I had read the FAQ quite carefully. It was not mentioned anywhere in the aforementioned FAQ that deletion also applied to duplicates. But soon after, #9 was revised    It now reads        The system will  negatively-scored, unlocked, and unanswered questions (both open and closed, including as duplicates) that are older than 30 days. (RemoveDeadQuestions)        To recap, about 14 months ago a post of mine was closed as a duplicate. Yesterday, I edited the question  and about 12 hours later the question was automatically deleted by the system  Why did the deletion happen? In the past, I have had other questions closed as duplicates but they were (as far as I know) never deleted by the system.   I think this is a bug, am I right?    2nd UPDATE (June 2019) For users who find themselves in the same predicament, members of EL&U kindly resurrected the , it then received three answers, and it now has a positive score of +5. The question remains open to this day.

What circumstances can cause a question or answer to be deleted, and what does that actually mean?    How can a post be deleted? When can't I delete my own post? Can I still see my post even after it's deleted? Can I see a list of my deleted posts? How can I undelete one of my posts? What does deletion mean for a post? How do votes to delete work? What are the criteria for deletion? What else should I know about deleted posts? If I flag my question with a request to delete it, what will happen?       For more information, see the articles about  and  in the .


I have windows 7 and do NOT want windows 10. I have the windows logo in my tray and have removed it twice. It always comes back.     What I want is a SIMPLE way to prevent windows 10 from being installed on my computer. Any help appreciated.

I cancelled the Microsoft Windows 10 Reservation and uninstalled KB3035583, but Windows 10 is still trying to install.   After I uninstalled KB3035583 and restarted my laptop as instructed, I could not find KB3035583 to hide it.   Now Windows 10 is sitting in my Windows Update saying that it will install when I restart my computer.


I've been wondering what's the difference of using <? and <?php. For example in this lines of code.  function getWallboard() {      $.ajax({     type: "POST", url: "quality_control/qc_ajax.php", data: "action=get_queue_totals&wallboard=<? echo $_REQUEST['wallboard'];?>", success: function(msg){ $("#queue_nav").fadeIn("fast");         $("#queue_nav").html(msg);     } });              $.ajax({     type: "POST", url: "quality_control/qc_ajax.php", data: "action=getQCWallboard&qctype=<?php echo $_REQUEST['qctype'];?>&wallboard=<? echo $_REQUEST['wallboard'];?>", success: function(msg){ $("#wallboard").fadeIn("fast");         $("#wallboard").html(msg);     } }); }   I've been getting error for some instance. Like If I change <? to <?php or <?php to <?, some of my code block doesn't work.   This is my first post. I hope I can get ideas about the use of this.

Here's the information :     There are four different pairs of   opening and closing tags which can be   used in PHP. Two of those, <?php ?>   and <script language="php"> </script>,   are always available. The other two   are short tags and ASP style tags, and   can be turned on and off from the   php.ini configuration file. As such,   while some people find short tags and   ASP style tags convenient, they are   less portable, and generally not   recommended.   In my experience most servers do have short tags enabled. Typing  <?=   is far more convenient than typing  <?php echo    The programmers convenience is an important factor, so why are they not recommended?


Let $x_i$ be independent Bernoulli random variables with success probabilities $p_i$. That is, $x_i=1$ with probability $p_i$ and $x_i=0$ with probability $1-p_i$.  Is there a closed expression or an approximate formula for the distribution of the sum $\sum_i x_i$?

If I wanted to get the probability of 9 successes in 16 trials with each trial having a probability of 0.6 I could use a binomial distribution. What could I use if each of the 16 trials has a different probability of success?


There is only one way my PDO query returns result I want, but proper prepared statement gives out only column name.  This returns column name instead of queried row:  $queryPrice = "SELECT :zone FROM express WHERE kg >= :kg LIMIT 1"; $stmt = $conn->prepare($queryPrice); $stmt->bindParam(':zone', $zone, PDO::PARAM_STR); $stmt->bindParam(':kg', $_SESSION['weight'], PDO::PARAM_STR); $stmt->execute(); $price = $stmt->fetchColumn();   This works, but is vulnerable to injection:  $queryPrice = "SELECT $zone FROM express WHERE kg >= :kg LIMIT 1"; $stmt = $conn->prepare($queryPrice); $stmt->bindParam(':kg', $_SESSION['weight'], PDO::PARAM_STR); $stmt->execute(); $price = $stmt->fetchColumn();   Why doesn't prepared statement for column name work?  Is there a safe way to achieve desired results?

Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh->prepare('SELECT * FROM :table WHERE 1'); if ($stmt->execute(array(':table' => 'users'))) {     var_dump($stmt->fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1"


I would like to use beamer's fonts in a standard LaTeX article.  Something like:  \documentclass{article}  \begin{document} bla $bla$ \end{document}   But with everything with beamer's fonts inside?  I have found how to change the math fonts only (using  package) but I would like to change also the text fonts.

How do I typeset an entire document in sans-serif, e.g. Helvetica, without littering the document with font changes for every heading/paragraph, etc.? Like in , but with the paragraphs all in sans-serif.  For example, I've seen documents typeset in Computer Modern and then switched to Palatino, but can I do the same with Helvetica with a few commands at the beginning?  (And please don't tell me to use a serif font for body copy / paragraphs. I know. I'm trying to use latex to typeset my resume to look like the one I've created in a word processor, which is hard to maintain but looks good. I'm hoping latex will let me do more advanced formatting/layout, separating content from form.)


\begin{eqnarray*}   % \nonumber % Remove numbering (before each equation)     (a, b) &=& \{ x \in X | a < x < b \} \\     (a, b] &=& \{ x \in X | a < x \leq b \} \\     [a, b) &=& \{ x \in X | a \leq x < b\} \\     [a, b] &=& \{ x \in X | a \leq x \leq b \}.   \end{eqnarray*}   What's error?   Missing number, treated as zero. <to be read again>                     a l.281     [a, b]                  &=& \{ x \in X \mid a \leq x \leq b \}.

I tried to find a topic here on this (possible problem) but I didn't.   I reported it at  but Tim Hoffmann pointed me that it is not a problem of editor. After tested with nano and pdflatex I'm posting here.  The minimal code produces errors. OK, we can solve it using \\{}.   But is this a problem with TeXlive 2014 or there are some good reasons to have that behavior.  \documentclass{report} \begin{document} test\\ [foo]  test\linebreak [foo]  test\newline [foo] \end{document}      ! Missing number, treated as zero.                        f l.3 test\ [foo]


How to edit breadcrumb info without install any drupal module?  Example: blog Home >> blog >> admin's blog  I want to remove admin's blog  I cant find node--blog.tpl.php file.  I only can find node.tpl.php file.    Many Thank.

I want to hide the user's blog link that appears on blog entries e.g Anonymous's blog  How can I do this in node--blog.tpl.php?  I tried hide($content['author']); but that doesn't seem to work.


I'm wondering what command I can use to see all the hardware in any PC, or at least some of it (for example, model of the motherboard). I'm pretty new on Linux, I'm using a lightweight version to boot in computers that I had to make a format, and previous back-up.  Some of these PCs are old, or with a very specific hardware and sometimes it's hard to find drivers.

How can I check what hardware I have? (With BIOS version etc.)


Not to print, I want the actual value with less precision. For example if I say:   numb = 1.23456789123456789 print "num %0.2f" % numb   then it'll display it as having only 2 decimal places   num 1.23   but in reality the value for numb will remain the same. How do I convert numb so that it will actually have the value of 1.23?   The purpose is that I'm trying to send this value into an api and the value is too precise for the api which is causing an error, the only things I can find online are about displaying a less precise value but not actually changing the value.   Edit: I wanted to clarify that I want it rounded down. I know math.floor would do that but it only rounds to integers. Is there a function that rounds down but with decimals as well?  Note: I'm new to Python so code samples are preferred, thanks!

I want a to be rounded to 13.95.  >>> a 13.949999999999999 >>> round(a, 2) 13.949999999999999   The  function does not work the way I expected.


Question: Integrate$$\int\limits_0^1dx\,\frac {\log(1-x)\log^2(1+x)}x=-\frac {\pi^4}{240}$$   I'm curious as to if there is a way to integrate this. I've tried using integration by parts to get$$I=-\frac {\pi^2}6\log^22+2\int\limits_0^1dx\,\frac {\operatorname{Li}_2(x)\log(1+x)}{1+x}$$However, I'm not sure how to continue even further. The polylog in the second integrand seems a bit intimidating and I don't see how the first term even helps.


I am wondering if this structure can confuse search bots and prevent them from identifying the contents of the H1.  For example, in the code below, can the bot identify "Main Text" as the H1 content?
Main  Text

Does the  element have any SEO side-effects? Are there any semantic preferences between the following two or parsing differences between search engines?  Clean
:
Search Optimised Heading
   vs  in
:
Search Optimised Heading


According to the General Theory of Relativity, the coordinate time distance per spacetime distance traveled by a particle freely falling into a black hole gets closer and closer to $0$ as the particle approaches the event horizon   $$\mathrm{d}s^2 ~=~ -\left(1-\frac{2M}{r}\right)\mathrm{d}t^2 + \left( 1-\frac{2M}{r} \right)^{-1}\mathrm{d}r^2 + \dots.$$  Equivalently, an observer looking from the outside will never see the particle cross the event horizon, even if he/she looked for an arbitrarily long time. However, Hawking radiation implies that black holes don't last forever, but instead shrink and fade away? What happens to everything that is "currently" falling into the black hole during that time?   Edit: What this seems to imply is that as a particle gets close to the event horizon, the rate and intensity of Hawking radiation will increase and increase until most of the mass of the black hole is ejected, in the form of Hawking radiation, out towards the falling particle.

Recently, I read in the journal  that Stephen Hawking wrote a paper claiming that black holes do not exist.  How is this possible? Please explain it to me because I didn't understand what he said.  References:   Article in Nature News:  (Zeeya Merali, January 24, 2014). S. Hawking, Information Preservation and Weather Forecasting for Black Holes, .


I'm writing a formal legal memo and could not find any explicit form of writing a plural letter grade (as in the example below).  Timmy made one C. His other grades were all As and Bs. (A's and B's?)

When writing (a blog post, script, etc..) what is the proper way to indicate two or more instances of a single letter? For instance, in Monty Python's Bookshop Sketch:     C: I wonder if you might have a copy of "Rarnaby Budge"?      P: No, as I say, we're right out of Edmund Wells!      C: No, not Edmund Wells - Charles Dikkens.      P: (pause - eagerly) Charles Dickens??      C: Yes.      P: (excitedly) You mean "Barnaby Rudge"!      C: No, "Rarnaby Budge" by Charles Dikkens.  That's Dikkens with two Ks, the      well-known Dutch author.      P: (slight pause) No, well we don't have "Rarnaby Budge" by Charles Dikkens      with two Ks, the well-known Dutch author, and perhaps to save time I      should add that we don't have "Karnaby Fudge" by Darles Chickens, or      "Farmer of Sludge" by Marles Pickens, or even "Stickwick Stapers" by Farles      Wickens with four M's and a silent Q!!!!!  Why don't you try W. H. Smith's?      C: Ah did, They sent me here.   I had always believed that plural never uses an apostrophe before the 's' (it's only used for possession), but I have rarely seen in written material the format "four Ms". (On a side note, whoever wrote  also used "two Ks".)  On a side note, and perhaps this should be a separate question, if a Compact Disc is a CD, then two Compact Discs would be two CDs right? (I see "CD's" written everywhere)


Groups are rarely mentioned during the first semester, but they appear in linear algebra exams. This is an example and my idea which undoubtedly lacks formal language:  If possible, find numbers $a,b \in \mathbb R, z\in \mathbb C$ so that the set $$S=\{a-bi,a+bi,z\},$$ consisting of different complex numbers forms a multiplicative group. Justify the existence or non-existence of such numbers. This is my attempt, please, correct me. As a student, I have to be $mathematically$ $literate$.  Closure under multiplication, the existence of identity and inverse element imply one of the three elements is 1 an the other two are inverse. $$a\pm bi\notin \mathbb R$$ because there would be two equal elements, therefore, $z=1$ and $$a\pm bi=\frac{1}{a\mp bi}$$ Since the set is closed under multiplication, any power of each element must be in that set. Let me take an arbitrary number x and its inverse: $x^z\in S, z\in \mathbb Z \implies x^z=\frac{1}{x} \implies x^{z+1}=1.$ If I write x in the trigonometric form: $$x=\lvert x\rvert(\cos\alpha + i\sin\alpha)$$ I have to find an odd exponent so that $$x^z=1, x\ne\pm1.$$ $\implies$ for example: $$x^z=\lvert x\rvert(\cos3\alpha+i\sin3\alpha)=1$$ For $\alpha=-\frac{\pi}{3}$: Is the solution: $$S=\{\frac{1}{2}+\frac{\sqrt3}{2}i,\frac{1}{2}-\frac{\sqrt3}{2}i,1\}$$ Every critic is helpful.

Groups are rarely mentioned during the first semester, but they appear in linear algebra exams. This is an example and my idea which undoubtedly lacks formal language: If possible, find numbers $a,b \in \mathbb R, z\in \mathbb C$ so that the set $$\{a-bi,a+bi,z\},$$ consisting of different complex numbers forms a multiplicative group. Justify the existence or non-existence of such numbers. This my attempt, please, correct me. As a student, I have to be mathematically literate.  Closure under multiplication, the existence of identity and inverse element imply one of the three elements is 1 an the other two are inverse. $$a\pm bi\notin\mathbb C\setminus \mathbb R$$ because there would be two equal elements, therefore, $z=\pm1$ and $$a\pm bi=\frac{1}{a\mp bi}$$ $$\implies a^2+b^2=1,$$ so the set looks like this: $$\left\{a-\sqrt{1-a^2}i,a+\sqrt{1-a^2}i,1\right\}$$ Every critic is helpful.


I know it isn't possible to learn a spell through words alone, it has to come in a written form. So would it be possible for a Bard to create a spellscroll and then let the wizard learn it? Assuming the spellscroll is of a spell on the wizard spell list.  This question is quite similar to  although this assumes teaching directly.  I'm asking for RAW answers.

What are the requirements for a wizard to successfully copy a spell from a scroll into their spellbook?  First, I’m thinking that copying a spell from a scroll is similar to copying a spell from my own book into another book (as the scroll is in my possession just like my spellbook), but I could be wrong on this too.   Otherwise, the cost goes to 2 hours and 50 gp per spell level to copy (as opposed to the 1hr & 10gp).  It seems like one would have to succeed the intelligence check and pay the cost in terms of time and gold. But then I’m wondering about the order in which one would make the check and spend the resources (hopefully the check comes first, so as to not waste time and gold in the unfortunate event of a failed check).


I want to load a path to picture from config file in order to show different pictures on different webapps.  Here I have  <add key="logoFileName" value="~/images/logo.png" />   And I want to use it like  <img src="@System.Configuration.ConfigurationManager.AppSettings["logoFileName"]" height="65" />   But .net only show "~/images/logo.png", wich must be interpreted by .net as well.  How to perform this in order to see the logo?

In my applications, I often have to use relative paths. For example, when I reference JQuery, I usually do so like this:  <script type="text/javascript" src="../Scripts/jquery-1.2.6.js"></script>   Now that I'm making the transition to MVC, I need to account for the different paths a page might have, relative to the root. This was of course an issue with URL rewriting in the past, but I managed to work around it by using consistent paths.  I'm aware that the standard solution is to use absolute paths such as:  <script type="text/javascript" src="/Scripts/jquery-1.2.6.js"></script>   but this will not work for me as during the development cycle, I have to deploy to a test machine on which the app will run in a virtual directory. Root relative paths don't work when the root changes. Also, for maintenance reasons, I cannot simply change out all the paths for the duration of deploying the test - that would be a nightmare in itself.  So what's the best solution?  Edit:  Since this question is still receiving views and answers, I thought it might be prudent to update it to note that as of Razor V2, support for root-relative urls is baked in, so you can use   <img src="~/Content/MyImage.jpg">   without any server-side syntax, and the view engine automatically replaces ~/ with whatever the current site root is.


I remember having heard one before but can't say how it went. The phrase says that what initially seemed like a disadvantage — became an advantage. If anyone knows anything even similar to this definition, it'd be much appreciated.

I tried on google every word and phrase I could come up but I just couldn't find it. I'm pretty sure I've seen this word before and it's english.


Ok, All of us saw the overwhelming power of the T-1000, and the lucky way that the heroes used to destroy him... why not send another one? just with two clear instructions "kill John Connor and stay away from a foundry"

So you've failed once, so you send back your shiniest poly-mimetic alloy terminator, but it fails because the resistance sent back a reprogrammed T-800! You know, or could reason that the T-800 would have to have encountered the targets of the T-1000, and they would have become familiar with each other as they evaded your near perfect killing machine.  Why not send back another with real infiltration programming (the T-800 is supposedly an infiltration unit, no?) so that it spends some time getting Connor to grow familiar with him, fooling him into thinking they are chased and then when he least expects it, the unit turns on him.  Is Skynet not capable of thinking in this out of the box manner? Did it not have enough T-800s to send back? Was it just designed by a physicist, and thus brute-forced every problem?


We have a series $a(k)$ with positive (real) members. We know that $\sum_{k=0}^{\infty}a(k)$ is convergent. Let $r(k)$ be $\sum_{j=k}^{\infty}a(j)$. Show that $\sum_{k=1}^{\infty} \frac{a(k)}{r(k)}$ diverges.  I have tried the ratio, root and condensation tests but none of them yielded anything.

Let $\displaystyle \sum a_n$ be  convergent series of positive terms and set  $\displaystyle b_n=\sum_{k=n}^{\infty}a_k$ , then prove that $\displaystyle\sum \frac{a_n}{b_n}$ diverges.   I could see that $\{b_n\}$ is monotonically decreasing sequence converging to $0$ and I can write $\displaystyle\sum \frac{a_n}{b_n}=\sum\frac{b_n-b_{n+1}}{b_n}$, how shall I proceed further?


I want to get the relative path from one file to another.  In other words, if I input the file foo/foobar/dafool.html and foo/style.css, how do I end up with ../style.css?  I'm using Java.

Given two absolute paths, e.g.  /var/data/stuff/xyz.dat /var/data   How can one create a relative path that uses the second path as its base? In the example above, the result should be: ./stuff/xyz.dat


I am using enumerated type declaration. I can't print it.  So far I have written the following code. The question is how to print a enum type variable?       #include <stdio.h> int main()     {         enum day {monday,tuesday,wednwsday,thrusday,friday,saturday,sunday};         enum day week_st, week_end;     week_st = monday;     week_end = friday;     if(week_st == monday)     {         printf("%s\n",week_end);     }     return 0; }

Here's what I am trying to do:    typedef enum { ONE, TWO, THREE } Numbers;   I am trying to write a function that would do a switch case similar to the following:   char num_str[10]; int process_numbers_str(Numbers num) {   switch(num) {     case ONE:     case TWO:     case THREE:     {       strcpy(num_str, num); //some way to get the symbolic constant name in here?     } break;     default:       return 0; //no match   return 1; }   Instead of defining at every case, is there a way to set it using the enum variable like I am trying to do above?


I have a line, that looks like this.   Das,Dwda,3145124,4,"7,5",6,"7,5",6,8,7,51,"5,5",10,17,"83,5"  I want to change all commas inside double quotes to a period with some command in bash like awk or sed.

I have a input file delimited with commas (,). There are some fields enclosed in double quotes that are having a comma in them. Here is the sample row  123,"ABC, DEV 23",345,534.202,NAME   I need to remove all the comma's occuring within inside the double quotes and the double quotes as well. So the above line should get parsed into as shown below  123,ABC DEV 23,345,534.202,NAME   I tried the following using sed but not giving expected results.  sed -e 's/\(".*\),\(".*\)/\1 \2/g'   Any quick tricks with sed, awk or any other unix utility please?


I have a multiline string, like this:  tt = """ some text myvar=foo some more text """   Now what i want to do is to extract the value behind 'myvar=', in this case 'foo'.  I tried like this:  import re m = re.match('^myvar=(.*)$', tt, flags=re.MULTILINE) if m:     print(m.group(1))   But mis always None. It only works with single line strings, like:  tt = 'myvar=foo'   What am I missing? I am new to python, but not to regex.

What is the difference between the search() and match() functions in the ?  I've read the  (), but I never seem to remember it.  I keep having to look it up and re-learn it.  I'm hoping that someone will answer it clearly with examples so that (perhaps) it will stick in my head.  Or at least I'll have a better place to return with my question and it will take less time to re-learn it.


I have been trying to get a code right but somehow it gets wrong. My code is the following below:  from Tkinter import * import time  def show():     p=password.get()     o=open('C:\Working\Documents\Aditya\Write To.txt', "w+")     o.write(p)     o.close()     time.sleep(2)     app.exit()  app = Tk() password = StringVar() #Password variable passEntry = Entry(app, textvariable=password, show='*', width="40").pack() submit = Button(app, text='OK',command=show, width="20") submit.pack() app.geometry("400x400")   app.mainloop()   and the error I get is :  Exception in Tkinter callback Traceback (most recent call last): File "C:\Python26\lib\lib-tk\Tkinter.py", line 1410, in __call__ return self.func(*args) File "C:\Working\Documents\Aditya\Password.py", line 10, in show app.exit() File "C:\Python26\lib\lib-tk\Tkinter.py", line 1722, in __getattr__ return getattr(self.tk, attr) AttributeError: exit   if you can please help me.

How do I end a Tkinter program? Let's say I have this code:  from Tkinter import *  def quit():     # code to exit  root = Tk() Button(root, text="Quit", command=quit).pack() root.mainloop()   How should I define the quit function to exit my application?


I would like to investigate the correlation of visually and automated assesed amount of emphysema (%) in CT-scans.  visual: categorical data (visual score 1-4, score 1= 1-25%, score 2= 26-50%, score 3=51-75%, score 4= 76-100%)   automated: interval scaled data (1-100%)   Since the data is not parametric, I thought about to use a spearman correlation test.  Is this correct? Is there any other test that would fit better?

I'd like to estimate the correlation between:  An ordinal variable: subjects are asked to rate their preference for 6 types of fruit on a 1-5 scale (ranging from very disgusting to very tasty) On average subjects use only 3 points of the scale.  A continuous variable: the same subjects are asked to quickly identify these fruits, which results in an mean accuracy for the 6 fruits.   Is Spearman rho the best method to analyze these data and/or are there other good methods I could consider?


Is there a nice way to arbitrarily force a figure into a location in the page, in an ad-hoc way. That is, after everything is written, just tell latex where to place it without changing any text.  I ma working with a CV template and don't want to change much, so I am looking for this way of achieving this. Any suggestions are welcome, thank you.  Edit I am not referring to in-text floats. Rather, I would like to "stick it on" in an arbitrary location.

I have a problem when a lot of figures are in question. Some figures tend to "fly around", that is, be a paragraph below, although I placed them before that paragraph. I use code:  \begin{figure}[ht] \begin{center} \advance\leftskip-3cm \advance\rightskip-3cm \includegraphics[keepaspectratio=true,scale=0.6]{slike/visina8} \caption{} \label{visina8} \end{center}\end{figure}   to place my figures. How can I tell latex I REALLY want the figure in that specific place, no matter how much whitespace will be left?


My issue is that I'm trying to write variable names in italic, but as some of them have underscores in their names, LaTeX assumes that I am writing an equation and it messes up the rest of my document after that point. Here is a sample of my code: As variable \textit{sensor.linear_acceleration} is a matrix  The underscore in linear_acceleration is what makes my whole document math modded, and is a matrix renders as if it was an equation. How can I display that underscore in italic without LaTeX making everything an equation?

I need to output the below text but since \ is a special character, I cannot:  [RegularExpression(@"\d+")]   Also sometimes I need use dollar sign $ as well but it seems to be a special char, too.  What is the way to escape those in LaTeX?  UPDATE:  I used \verb as suggested but I am unable to run commands inside it. Also, in the output the font and the opacity of the text is different than the default one:  \verb|[RegularExpression(\newline @"\d+")]|


In my house there is no internet connection, then I can't use the 'sudo apt-get install' command. I wonder if I can download a package, put it in my computer in a specific folder, and just get the terminal to install and run it? (EDIT:)Sorry, I searched for a question like mine but didn't find any, so I posted this.

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


I am writing a function that is recieving a folder path as an arguemnt. I want her to add into a dictionary what's inside the folder (like dir in CMD)  How can I do this ?  Thank you in advance, Iliya

How do I get a list of all files (and directories) in a given directory in Python?


I am trying to edit out "Dear Baju" in . But when I click edit, somehow, "Dear Baju" is not there:    But after saving it's back again:

I stumbled upon the following issue.  starts out with "Dear friends", as can be seen in the image below (and hopefully by following the link).    However, when I go to edit the question for some clean-up, I don't see this in the source of the question:    My first guess was that a suggested edit is hanging around somewhere, but I don't see one. So, what's going on? Am I the only one seeing this? Bug? Cache? (New feature? Are we all friends now? ;) )


how can i make this program to accept both upper and lower case id's. The id when read from file is of upper case.The id's present are in the form of S2345. Help please.     cout << "Enter client ID TO Change email";    cin >> ids;    for(int i=0; i<rec; i++)          if(client[i].ID == ids){             cout << "\nEnter New email\n";             cin  >> client[i].email;          }

I want to convert a std::string to lowercase. I am aware of the function tolower(). However, in the past I have had issues with this function and it is hardly ideal anyway as using it with a std::string would require iterating over each character. Is there an alternative which works 100% of the time?


Find the derivative of the function using the limit definition of derivative to:  $f(x)=\sqrt x$

Using $$\frac{f(x+h)-f(x)}{h}$$ how would I find the derivative of $f(x)= \sqrt{x}+1$   The answer is $$\frac{1}{2\sqrt{x}}$$ but I keep getting $$\frac{1}{2 + 2\sqrt{x}}$$


I'm working on my Spring MVC project. So, here is my controller's login method:  @PostMapping("/login")     public String login(         Model model,         @ModelAttribute("user") @Valid User user, BindingResult result) {         if (result.hasErrors() )             return "login-form";          try {             userService.login(user);         } catch (UserNotFoundException | IncorrectPasswordException e) {             model.addAttribute("message", "Incorrect email or password");             model.addAttribute("tryAgainLocalHref", "/showLoginForm");             return "authorization-failure-page";         }          //debug:         System.out.println(user.getFirstName() + " " + user.getLastName());          return "authorization-success-page";     }    UserService's login method:  @Override     @Transactional     public void login(User user) throws UserNotFoundException, IncorrectPasswordException {         User currentUser = userDAO.getUser(user.getEmail());         if (currentUser == null)             throw new UserNotFoundException();         UserSecurity currentUserSecurity = getUserSecurityByUserId(currentUser.getId());         String inputPasswordHash =              SecurityManager.hashPassword(user.getPassword(), currentUserSecurity.getSalt());          if (!inputPasswordHash.equals(currentUserSecurity.getPasswordHash()))             throw new IncorrectPasswordException();          user = currentUser;                 //debug:                 System.out.println(user.getFirstName() + " " + user.getLastName());      }    Here you can see that in UserService 'user' object is replaced on 'currentUser'. In my business logic, 'user' has only two not-null fields: email and password, and 'currentUser' has four not-null fields: email, password, firstName, lastName. As you can see, in controller's login method I print user's firstName and lastName. And it writes: null null. But why??? It is replaced by 'currentUser' in UserService! When I print user's firstName and lastName fields in UserService, it writes current firstName and lastName from database! So why does 'user' object changes have no impact outside the method? 'User' is non-primitive type...

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


I have repeatedly been given the option to update to Ubuntu 20.04 LTS by the Software Updater. When I click the "Upgrade..." for it to proceed, the only thing that happens is that the Software Updater closes.  I have tried, from the terminal: sudo apt-get update sudo apt-get dist-upgrade  Results, nothing but another puzzling issue that is unrelated, pertaining to JavaFX. phil@UbuntuDesktop:~$ sudo apt-get dist-upgrade Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages have been kept back:   libopenjfx-java libopenjfx-jni openjfx 0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded. phil@UbuntuDestktop:~$  Any thoughts on how to proceed, or what might be hanging things up?

I want to use do-release-upgrade to upgrade from 18.04 to 20.04, but I can't do that do-release-upgrade Checking for a new Ubuntu release There is no development version of an LTS available.  It seems that  is used, and it still points to 18.04. Do you know when (or how?) can I upgrade to 20.04?


I have a file test.txt which contains file names like below where some file names will have spaces and some will not.   Mon - Tue corrected item.csv Sat -Sun incorrect item.csv Wed_THU_corrected_item.csv   Now I have a script where I have a for loop that is intended to find these files which are listed in test.txt at a particular "path" where files will come daily just to make sure files exist. So please let me know how I can match such files that have spaces in their name.  for file in `cat test.txt` do     if [ ! -f path/$file ];     then action item     fi done

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


If we allow some $g(x) = \frac{\sin(x)}{x}$ such that $g(0) = 1$ and also some $f(x)$ where:  $$f(x) = \prod_{k=1}^{\infty} 1 - \frac{x^2}{\pi^2k^2}$$  Then it is said f and g are equal. But my question is, what are the specifics besides the fact that:  Both have the same value at $x=0$. Both have the same roots, and an infinite number of them of course.  I feel like those two criteria definitely don’t justify equality, so I would like to know what legitimately justifies it.

How to prove the following product? $$\frac{\sin(x)}{x}= \left(1+\frac{x}{\pi}\right) \left(1-\frac{x}{\pi}\right) \left(1+\frac{x}{2\pi}\right) \left(1-\frac{x}{2\pi}\right) \left(1+\frac{x}{3\pi}\right) \left(1-\frac{x}{3\pi}\right)\cdots$$


I've been trying to create a 400m buffer in a polygon layer in QGIS 2.18 and it seems like I may be doing something wrong compared to how the tool used to work.    Does the tool still use the units of the CRS?    When I try to create a 400m buffer or even a 10m buffer I end up just getting a large buffer that definitely isn't either one of those distances.   I'm going to Vector->Geoprocessing Tools->Fixed Distance Buffer and setting things as follows in the screen shot.  GeoJSON is in EPSG2768.     Seems like the buffer tool wasn't using the defined CRS units for my layers.  Checked the output buffer layer and it was using WGS84 instead of EPSG2768.  CRS for the project and all the layers was set to EPSG2768.  Things didn't work until I changed the CRS for the buffer layer and then re-ran the buffer tool.  I set up a couple virtual machines to test things out with mixed results.  Fresh Xunbuntu VM with QGIS installed and the buffer tool worked right off the bat, but a fresh KDE Neon VM with QGIS had the same issue I initially posted about.  Things are working now though.

I  have had no luck getting the buffer tool to accept anything but degrees as units of measure.  I have found lots of stuff saying the layer needs to be reprojected and saved but it hasn't worked at all for me.   Is there a way I could create a buffer without using ftools or at least force the units to meters somehow?  As a workaround I converted meters to degrees (lat) and used that but the final product needs to be as close to reality as possible.  Things I've tried:   setting every unit option I could find to meters (where possible). setting everything to NAD83/Maryland (data is for Washington, DC) and saving it as such (as layers in ESRI shape files). reimporting the reprojected layers setting relevant layers to Google Mercator   The was tried followed by creating a buffer. Many were tried in combination. QGIS 1.7.3 Slackware64 current (qgis from SBo-13.37 repo, tried on multilib and plain 64it with same results)


I've a permission problem on my dedicated webserver, but I'm not able to understand what I'm doing wrong.   Ubuntu 14.04 Kernel 3.19.2 Apache 2.4.7 PHP 5.5.9 MySQL 5.5   (all from official repository, except for kernel. It comes from vivid repository)  I've installed apache2 and it starts with user www-data  I've set a virtualhost /home/USER1/public_html (where ownership is USER1:USER1)  so If I install any CMS (like joomla, wordpress or phpbb) I get lots of permission problems and I'm forced to set chmod to 777 (OMG! Against common sense) in order to install one of them.  The "standard" mode for this kind of CMS is, as I understand 755 for directory 644 for files  But if I set these permissions, I cannot do anything with the cms (install anything or update it. Files will be considered unwritable). Same problem with 775  So the problem is that my webserver needs all permission to "OTHER" and not just for USER (or at least for GROUP)  In order to avoid this trouble I've added USER1 to www-data group  usermod -a -G www-data USER1   but files are still unwritable with 775 or 755. The only mode allowed still 777 (OMG it's horrible to write it 2 times in the same post :D )  What is the problem and how can I fix it?

I want to stop having to use sudo everytime I work in /var/www. How can I do that? I simply want to put all of my sites into this directory and work with them without too much pain.


Pressing a key on the keybord results in different types of characters in different OS's. e.g. pressing the up arrow in windows will result in a nother sequence of characters then pressing the same key in linux.  So the question is: Which "part" of an OS is responsible? Especially when looking at GNU\linux OS's since "linux" is only the kernel.

Suppose I press the A key in a text editor and this inserts the character a in the document and displays it on the screen. I know the editor application isn't directly communicating with the hardware (there's a kernel and stuff in between), so what is going on inside my computer?


If it wasn't raining I would have gone to work.   I was told this sentence isn't correct, because it should have "weren't" instead of "wasn't":     If it weren't raining I would have gone to work.   Is this actually true, and if so, why?

If I was... If I were...   When is it correct to use "If I was" vs. "If I were" in standard English?


Today I tried to upgrade to Ubuntu 15.04 from 14.04. I did the folowing commands:  sudo apt-get update sudo apt-get upgrade sudo do-release-upgrade  But during the last command, after lots of get messages I get the following error:  Error authenticating some packages. Continue?   It was not possible to authenticate some packages. This may be a  transient network problem. You may want to try again later. See below  for a list of unauthenticated packages.   gettext  lib32stdc++6  libatomic1  libfftw3-single3  libgfortran3  libgomp1  libitm1  libquadmath0  libstdc++6  libtsan0  onboard   Restoring original system state  Aborting   How can I upgrade without these errors? I have tried similar questions but with no success.

I am currently using Ubuntu 10.04. I know there is a 10.10 release, but can I upgrade directly to 11.04? Could you walk me through the steps please?


Which should I use in the next sentence?     Join us at/in our Spanish patio.

I am really confused.  Which preposition is correct?     She is in/at the park.   They are in/at the park.   I am in/at the park.   Should I use in or at in these sentences?


I have a table who is filled by thousands of registers, so I don´t want to affect them. I want to change type of column:   Table:  ----------------- TrainingHours ----------------- Id int(Primary key) Hours decimal(18,0)   in SQL I can just add design table and changed it manually, but I need to change it with script code to get something like  Hours decimal(18,2) //instead (18,0)   How can I make this change without sql designer?

Is there a way to alter the precision of an existing decimal column in Sql Server?


Why is electric charge quantized? It is said that charge quantization is a consequence of embedding the abelian gauge group in a simple non-abelian group as is done in theories of Grand Unification. Can somebody explain this in detail (show mathematical steps)? Or is there another explanation?

I read an unjustified treatment in a book, saying that in QED charge an not quantized by the gauge symmetry principle (which totally clear for me: Q the generator of $U(1)$ can be anything in $\mathbb{R}$) but for non-Abelian gauge symmetries the "charge" are quantized by virtue of this principle. Could someone give a hint (or reference) of the calculation showing that.


I don't even know where to begin on this one.  Let $A$ be a countable set. In other words, $|A| = |\mathbb{N}|$. I'm trying to prove that there doesn't exist an $x$ such that $\mathcal{P}x = A$.   Maybe a proof by contradiction? Suppose there was a set $x$ whose power set was countable ...

Is it consistent with ZF for there to exist a set $S$ such that the power set $P(S)$ is countable? If so, what is the weakest form of the axiom of choice needed to prove that no such set exists?


I have to prove that $\sum_{n=l+1}^{\infty} \sqrt{\frac{n}{2^n}} \leq C \sqrt{h\log(\frac{1}{h})}$ where $2^{-l} <h \leq 2^{-l+1}$?.

How do you prove $$\sum_{n=1}^{\infty} \frac {n}{2^n} = 2\ ?$$  My attempt: I have been trying to find geometric series that converge to 2 which can bind the given series on either side. But I am unable to find these. Is there a general technique to find the sum? This is a high school interview question and must be easy enough to solve in a few minutes.  Please give any hints for the first step towards a solution.


I read this book in my dad's collection at least ten years ago. I feel like the title had something to do with time, but I could be wrong. The cover has a brown bald head (you just see the back) approaching three young adults in what looks like a spaceship.   In the book, the main character is Caucasian and living in America, but then his dog does things it isn't supposed to do (like climb trees) and he realizes he's not in the time and place he thought he was. He meets a couple of other race-preserved people who were being raised as if in other times and places (I think there was a Chinese girl named Meilin? Or Mei-lan?).  They try to find a way back home from this planet populated by people who all have the same color skin and hair, they call each other either "Stan" for standard or "Norm" for normal, I can't remember which. There's also something about their houses being clear and shifting or adjusting according the what the inhabitants need...

I remember reading a story once where we had all interbred such that there were no longer any blacks, whites, Asians, etc.  We were all 'brown'.  Somehow they 'found' 5 children that were purebred 'races', and I don't remember much else.


Is it actually possible (and allowed ) for the same user to have more than one account in the same stack exchange? I think  should be possible as one could simply have a different email and login from that.But this would mean that he has an unfair advantage over the others as for example,  he can vote twice for the same post.

Take this example: .  I can imagine of any human reasons to create a new user account at SO, e.g. willing to restart with a clean (reputation) history. But particular this one is extreme. The user known as "icepax" currently already has 10 accounts, each involved in only one question/answer.  How and why would one do that? There is certainly more at matter here. Shouldn't it be our task to merge the accounts and inform the user in question about how to use SO and the OpenID properly?


Hi i have a situation similar as the exaple below (see code snippet). When appear "called button" and i click it the associated js event not work.  When i add an new element whit js (in the example through ".append()", but also with adding element after an ajax call to another page), this new element is not "identified" from the exist js code.  Which is the best way to resolve this?  Obviously this is a simple example to explain the problem, but i can not resolve the problem including the code in a function and call it when the new element appear becouse the real js code of included plugins is much to complex.    var calledButton = '
<button id="called-button">This is the called button</button>' $("#main-button").click(function() {   $("#response").append(calledButton);   $("#response").append("

Main button clicked"); });  $("#called-button").click(function() {   $("#response").append("

Called button clicked"); });    <button id="main-button">This is the main button</button>

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


Today i installed 7zip, furious ISO mount and mate power manager. FuriousISO is in my dash, whereas the other two are not.   All 3 show up in software center and in terminal ~$dpkg -l as installed. Im unable to open/use 7zip at all, and when trying to run power manager from terminal, it simply brightens the screen. (No GUI? Not compatible with Unity desktop?)  Was kinda aiming to personalize my power settings for when my machine is plugged/unplugged.   Thanks

I just installed 7zip from the Ubuntu Software Centre, but when I look for it in my applications, I can't find it. Even when I type "7z" in the terminal, it is telling me that 7zip is installed. How can I find the application and open it up? Thank you.


There's a gallery of  where all of the portraits have the same effect applied. What would that be called, and how can I do something similar using Adobe Photoshop?  For example:

Is there a tool like  available for Android or Windows systems? I'd like to  turn images into polygones/triangles like shown on the app site.


I was taught that with the word language, the definite article is used.         The English language versus English   The English language Teacher versus  English teacher      What are article usage rules for 'a/the English Language teacher'?

I can’t for the life of me figure out where to use a and where to use the — and where there is no article at all. Is there a simple rule of thumb to memorize?   The standard rule you always hear:     “If a person knows which item you are talking about then use "the"   . . . doesn’t clear things up for me, as I have no idea whether or not they know.


In ArcMap 10.7, I'm trying to use batch processing on a custom model. The problem I'm having as seen from the picture below, is that the output files are given the name of the first output file, even though I explicitly name them based on their input file, each of which is unique.  You can see in the picture that even though the output file names are different on process 1,2, and 3; when I actually open the tool it assigns the output name of each file as the first name on the list.   In the picture below, I've opened process #3 on the list.  In the list the output name is correct, but when I open that item its names after the first process.  It's the same no matter how many process iterations I add.    When I run the tool it appears that the first process writes a file with the output name, then each subsequent process writes over that file.    There's also a picture of my model:

I am running a model which I created with ModelBuilder at 10.3. The model is supposed to make a selection by attribute on a feature layer, and use that layer to clip a raster. The model is working fine when I run it, however if I try to use it in batch mode it gives unexpected results: I have many files with the same extent and content as the first line of the loop (of the batch).  The parameters of my models are:   the input feature layer against which a selection is specified the input raster (.BIL)to be clipped with the selected feature the SQL expression for the selection (of the type "FIELD" = 'value') the output folder and filename (with .BIL extension)   Basically, in the batch window the feature and raster parameters are fixed, I am only changing the SQL expression to point a different 'value', so that the output raster is clipped on different areas each time, and the filename name of the output.  Below is my model:


Is there any way to preprocess text files and skip these characters?  UnicodeDecodeError: 'utf8' codec can't decode byte 0xa1 in position 1395: invalid start byte

I received some text that is encoded, but I don't know what charset was used. Is there a way to determine the encoding of a text file using Python?  deals with C#.


I'm a mathematics undergraduate student and I think of studying  QM this summer. I've found two online courses given by professor Fredric Schuller  QM (). I look for a good text that I can use to accompany those lectures. I prefer those lectures since they are rigorous unlike most courses I've found on Youtube that are not rigorous enough for my tastes.   Which texts do you recommend? What about Principles of Quantum Mechanics by Shankar? does it go along with the QM course? if not, any other recommendations?  I've suggested the two books since when I skimmed through them, they seemed to be more rigorous than many other texts I skimmed through. Note also that It will be my first course to QM and GR.   Here are the titles of lectures of QM course (every lecture is about 110 minutes):         Axioms of Quantum Mechanics    Banach Spaces   Separable Hilbert spaces    Projectors,bars and kets   Measure Theory   Integration of measurable functions    Self adjoint and essentially self-adjoint operators    Spectra and perturbation theory    Case study: momentum operator    Inverse Spectral Theorem    Spectral Theorem    Stone's theorem & construction of observables    Spin    Composite systems    Total spin of composite system -   Quantum Harmonic Oscillator I   Quantum Harmonic Oscillator II   The Fourier Operator    The Schrodinger Operator    Periodic potentials I   Periodic potentials II

I'm interested in quantum mechanics book that uses high level mathematics (not only the usual functional analysis and the theory of generalised functions but the theory of pseudodifferential operators etc, certainly the modern mathematics). If there isn't something similar please give me a reference to the book that is strictly supported by mathematics (given a set of mathematically descripted axioms author develops the theory using mathematics as a main tool).


I have to find the extremas of $f(x, y, z)=x+y+z$ subject to $x^2-y^2=1$, $2x+z=1$.   I have done the following:   We will use the theorem of Lagrange multipliers.   The constraints are $$g_1(x,y,z)=x^2-y^2-1=0 \ \ , \ \ g_2(x, y, z)=2x+z-1=0$$   We are looking for $x$, $y$, $z$, $\lambda_1$ and $\lambda_2$ such that $$\nabla f(x, y, z)=\lambda_1 \nabla g_1(x, y, z)+\lambda_2 \nabla g_2(x, y, z) \tag 1$$ and $$g_1 (x, y, z)=0 \tag 2$$ $$g_2(x, y, z)=0\tag 3$$   $$(1) \Rightarrow (1, 1, 1)=\lambda_1(2x, -2y, 0)+\lambda_2(2, 0, 1)$$   So, we have that $$1=2\lambda_1 x+2\lambda_2 \\ 1=-2\lambda_1 y \\ 1=\lambda_2$$   So, we get $x=y$, right??   When we apply this at the first constraint $g_1(x, y, z)=0$ we get $-1=0$, or not??   What have I done wrong??

Find the global maxima/minima of $f(x,y,z) = x+y+z$ for points inside of $A = \{ (x,y,z) \in \mathbb{R}^3: x^2-y^2 = 1 \wedge 2x+z = 1 \}$   I renamed the conditions of $A$ to a function $g(x,y,z) = x^2-y^2-2x-z = 0$ in order to be able to use Lagrange multipliers.  Deriving $f$: $\nabla(x,y,z) = (1,1,1)$  Deriving $g$:   $g_x = 2x-2$ $g_y = -2y$ $g_z = -1$   By solving the Lagrange system:  \begin{cases} 1 = \lambda(2x-2) \\ 1 = \lambda (-2y) \\ 1 = \lambda (-1) \\ g(x,y) = 0 \end{cases}  I get that $(x,y,z) = (\frac{1}{2}, \frac{1}{2}, -1)$ for $\lambda = -1$. But that point is not inside A.  Is this enough to guarantee that $f|_A$ does not have either maxima nor minima?  (Since the second derivatives are all zero, the second derivative test doesn't give any information.)  Thanks!  EDIT:  By parametrizing $y = \pm \sqrt{x^2-1}$ and $z=1-2x$ and doing the composition with $f$ I get that $f(x, \sqrt{x^2-1}, 1-2x)$ is monotonically increasing and $f(x, -\sqrt{x^2-1}, 1-2x)$ monotonically decreasing. Would that prove that $f$ never reaches either maxima nor minima?


Here is a user-defined mixin for shallow cloning of objects:      function mixin(receiver, supplier) {       Object.keys(supplier).forEach(function(key) {          receiver[key] = supplier[key];       });        return receiver;     }     var supplier = {         a:{b:10}     };     var receiver = mixin({},supplier);   and according to my understanding assigning one object to other makes them equal since they have reference to same object literal and when one object changes its property it reflects on the other object too but the below tests puzzled me:      receiver.a === supplier.a //true     receiver.a = {b:20} //but     supplier.a //still {b:10} I expected {b:20}   What am I doing wrong here?? P.S I know about ES6 Object.assign() but this mixin is created just for my understanding.

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


I have seen work with introducing relativistic corrections to the momentum term of the Hamiltonian by taking higher order terms in the Taylor series, but do people work with $H = \sqrt{P^2 c^2 - m^2 c^4} - mc^2$ where $P$ is the ordinary spatial momentum operator? If not, why isn't this an interesting/useful case?  Note: of course this is just the free particle case. This is the simplest case, which is why I'm asking about it.

The Wikipedia  has a derivation of the Klein-Gordon equation.  It gets to this step:  $$\sqrt{\textbf{p}^2 c^2 + m^2 c^4} = E$$  and inserts the QM operators to get  $$\left( \sqrt{ (-i \hbar \nabla)^2 c^2 + m^2 c^4 } \right) \psi = i\hbar\frac{\partial}{\partial t} \psi$$  The article then says     This, however, is a cumbersome expression to work with because the differential operator cannot be evaluated while under the square root sign. In addition, this equation, as it stands, is nonlocal.   To fix this, the first equation is squared instead to get  $$\textbf{p}^2 c^2 + m^2 c^4 = E^2$$  after which the QM operators are inserted and the expression is simplified to get  $$-\hbar^2 c^2 \nabla^2 \psi + m^2 c^4 \psi = -\hbar^2 \frac{\partial^2}{\partial t^2} \psi$$  A couple things I don't understand.  First, are the solutions to this differential equation not exactly the same as the solutions to the first differential equation?  Both sides of the starting equation were squared, so it seems to me that regardless of the particular form of the resulting differential equation, both of them should have the exact same set of solutions.  Secondly, why is the first differential equation cumbersome to work with?  It seems like it would in fact be easier to work with, since the operator under the square root could be expanded in terms of a Taylor series and then you have an equation that is first order in time.  And finally, can someone elaborate on what nonlocal means? The linked article on the Wikipedia page didn't entirely help me understand it.


I have a dynamic sql statement that I want to fire off to SQL Server.  The base of the query is in a variable called query:  <cfset query ="select              ParcelID,             LTRIM(IIF(AddNum IS NOT NULL, ' ' + AddNum, '') + IIF(AddDir IS NOT NULL, ' ' + AddDir, '')  + ' ' + AddStreet + IIF(AddUnitNum IS NOT NULL, ' ' + AddUnitNum, '') + ' ' + AddCity + ', ' + AddState + ' ' + AddZip + IIF(AddZip4 IS NOT NULL, '-'+ AddZip4, '')) as Address         from PropertyParameters         where AddZip = '#URL.zip#'">   My problem is the areas where you see quote-space-quote plus field (ie.  ' ' + AddNum), the single quote adds more single quotes, and sends the following to sql server:  select ParcelID, LTRIM(IIF(AddNum IS NOT NULL, '' '' + AddNum, '''') + IIF(AddDir IS NOT NULL, '' '' + AddDir, '''')  + '' '' + AddStreet + IIF(AddUnitNum IS NOT NULL, '' '' + AddUnitNum, '') + '' '' + AddCity + '', '' + AddState + '' '' + AddZip + IIF(AddZip4 IS NOT NULL, ''-''+ AddZip4, '')) as Address from PropertyParameters where AddZip = 20001 and Score > 70;   as you can see, the quotes are doubled and fails in sql server. How do I overcome this?  Thanks.  UPDATE 1: I tried escaping the quote according to coldfusion instructions ('' and "") and that still didn't work. Thanks

I am coding in ColdFusion, but trying to stay in cfscript, so I have a function that allows me to pass in a query to run it with   <cfquery blah >   #query# </cfquery>   Somehow though, when I construct my queries with sql = "SELECT * FROM a WHERE b='#c#'"  and pass it in, ColdFusion has replaced the single quotes with 2 single quotes.  so it becomes  WHERE b=''c'' in the final query.  I have tried creating the strings a lot of different ways, but I cannot get it to leave just one quote.  Even doing a string replace has no effect.   Any idea why this is happening?  It is ruining my hopes of living in cfscript for the duration of this project


So i know that an open function is a function with the property that it sends an open interval to an open interval , but how to find a function which is open and not continous ?  Any hints ?  thanks

What is an example of an open map $(0,1) \to \mathbb{R}$ which is not continuous? Is it even possible for one to exist? What about in higher dimensions? The simplest example I've been able to think of is the map $e^{1/z}$ from $\mathbb{C}$ to $\mathbb{C}$ (filled in to be $0$ at $0$). There must be a simpler example, using the usual Euclidean topology, right?


I have no idea how to interpret this type of residual plot. The model is a logistic. Is there something wrong with the mean-variance relationship?

This question is sort of general and long-winded, but please bear with me.  In my application, I have many datasets, each consisting of ~20,000 datapoints with ~50 features and a single dependent binary variable. I am attempting to model the datasets using regularized logistic regression (R package )  As part of my analysis, I've created residual plots as follows. For each feature, I sort the datapoints according to the value of that feature, divide the datapoints into 100 buckets, and then compute the average output value and the average prediction value within each bucket. I plot these differences.   Here is an example residual plot:    In the above plot, the feature has a range of [0,1] (with a heavy concentration at 1). As you can see, when the feature value is low, the model appears to be biased towards overestimating the likelihood of a 1-output. For example, in the leftmost bucket, the model overestimates the probability by about 9%.  Armed with this information, I'd like to alter the feature definition in a straightforward manner to roughly correct for this bias. Alterations like replacing  $x \rightarrow \sqrt{x}$  or  $x \rightarrow f_a(x) = \cases{a & if $x<a$ \cr x & else}$  How can I do this? I'm looking for a general methodology so that a human could quickly scroll through all ~50 plots and make alterations, and do this for all datasets and repeat often to keep models up-to-date as the data evolves over time.  As a general question, is this even the right approach? Google searches for "logistic regression residual analysis" don't return many results with good practical advice. They seem to be fixated on answering the question, "Is this model a good fit?" and offer various tests like Hosmer-Lemeshow to answer. But I don't care about whether my model is good, I want to know how to make it better!


im having trouble connecting to MS SQL Server 2012 SP1 with regards to TLS Handshake. as stated by microsoft, SP1 only supports TLSv1 to TLSv1.1, if i'm not mistaken. I have been developing a spring/java application which uses JPA/jdbc to connect to the database but it requires me to use TLSv1.2 minimum. is there a way to enable TLSv1.2 on SQL Server 2012 SP1? or applying the SP2 packages to get the support for TLS 1.2 will not affect or has backward compatibility with old version of connectors.

The major browsers are moving beyond SSL3.0 and TLS1.0 . The PCI Security Council has declared an end-of-life date for these protocols to be considered sufficiently strong encryption.   We need to move away from these protocols, to use newer and stronger ones. On Windows servers, you can very easily disable these old protocols, and instead offer only TLS1.1 or greater.  However, as noted , Microsoft SQL Server 2008 R2 and SQL Server 2012 (Standard, at least) both will not start if those lower protocols are disabled.  However, there are a growing number of versions of MS SQL Server.  There are SQL Server Standard, Business Intelligence, Enterprise, Express, Web, and Compact editions.  And of course there is SQL Server 2008, 2012, 2014, and (in pre-release) 2016.  Which of these editions support or will support the use of only TLS1.1 or greater protocols?


How do i search for filenames containing a word (or multiple words), starting from some directory (not case sensitive) ?

I want to find a text file in my hard disk which contains a specific word.  Prior to Ubuntu 12.4 I used to start in the dash an application, I think it was called "Search for file...", whose icon was a magnifying glass.I can't find that simple application any more.


I have a JavaScript object   const categories = Object.keys(titles);   that looks like this  ["scifi","horror","comedy"]   I want to add "drama" to the object. I've tried   categories['drama'];    but that doesn't work. How can I add another category to this categories object?

How do I append an object (such as a string or number) to an array in JavaScript?


I enjoy cryptography, and like encrypting stuff hands on, for fun. I often send encrypted messages to friends. Trouble is, the easiest ciphers are also very insecure (for example, the Vigénère cipher and the Playfair cipher) and the most secure ones are plain impossible to use with just pen and paper (for example, RSA and AES)! I once even tried to encrypt a message using RSA (using just a calculator, obviously), but, even with some assistance, I gave up halfway through (my message was something like "Hello there!").                                                   Could someoneone suggest a cipher that strikes a reasonable balance between security and feasibility? I just want to have fun, so it's very important that I must be able to do the required calculations by hand, or at most, with the help of a calculator. I have the VIC cipher and a personally modified version of the ADFGVX cipher on mind, but I look forward to suggestions from more experienced cryptographers.                                                  P.S.: I was not sure what tags to add, so I hope my choice is relevant. My choice would have been "Recreational Cryptography"!

By "hand cipher", I mean a symmetric cipher for which encryption and decryption can can both be performed with a pencil on graph paper, consuming about 10-20 seconds per character by a proficient user. Additional simple tools, e.g. a deck of cards or a multiplication table, may be used to expedite the process. No mathematical proficiency is required other than mental addition, subtraction, and maybe multiplication.  Basically, it should be a cipher that someone of average mathematical abilities can master, and it should require no digital technology or cryptographic tools that cannot be constructed out of paper.  For example, four-square in CBC mode seems secure to me because CBC is a well established mode of operation and four-square seems to be a good block cipher as it accommodates large keys and seems to produce a random-looking output. However, the fact that four-square in CBC was never widely adopted before digital encryption became a consumer technology leads me to believe that someone broke the cipher and thus discouraged people from using it.  So is there any hand cipher that the best supercomputers would take years to cryptanalyze? If not, then for which hand cipher is the best known attack the most complex?


Is is possible to use an external drive to play Blu-ray discs on a MacBook? It has a Core2Duo processor and 9400m graphics. does it need any software, either paid or free?

I'd like to buy a Macbook Pro 15 inch instead of a Dell, and I know I can send video to the HDMI TV using the Moshi adapter.  My MacBook doesn't have a drive for Blu Ray discs. Is there a way to solve this?  I kind of want the navigation of chapters and extra features in a Blu Ray disc, so if using makemkv and a Sony external Blu Ray drive to make the Blu Ray disc into an .mkv file, that's not so preferred.  (Is one possible way to use the Sony external BD drive (about $180), and use bootcamp to boot up Windows 7 instead?  Although this method is not so preferred because it needs to boot up only Windows)


I would like to keep the preinstalled Windows 10 for the rare case I need it (I know that I will need Windows for Taxman). The Stream 11 I have is a 4GB RAM, 32GB eMMC, Celeron N3060 1.6gHz, 64 bit. I received it today, so it is brand new. Do I have enough space on it to run both OSs?  Is the processor good enough for this?  Is there a good tutorial to do this?  Windows 10 is already taking 14GB, 13.7GB are still available. Is there enough storage on it? I will add an SD card for my files so don't need the internal storage for that.

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I see a website which teach people to put something on top of the pot during cooking soup to prevent the soup coming out during cooking. What is the physical theory behind that?

This is an image I found via StumbleUpon    Does this actually work? If so, why?


I do something error, I transfer yesterday all post from draft to publish by my user, Now how can i return all this post to draft ??

The following code updates the post status of standard wordpress posts to 'Archived'.  UPDATE wp_posts SET post_status = 'Archived' WHERE post_status != 'static';   How can I make this only affect custom post types with the slug of 'cpt_operator'. I know I can do this from Wp-Admin but with over 2,500 posts its a huge task.


We have a 6 hour layover at SFO. Is that enough time to see the town? Is there a bus or should we take a taxi? What about our 2 carry-on 17 lb. bags?

Say a medium-ish sized bag that weighs 50 lbs (23 kg).


I am writing a simple bash script to check for disk usage on my system. The while loop should only print partitions that are at 85% or above. There are two partitions over 90% but only the first partition is being printed to output.  Code:  #!/bin/bash admin="foo@bar.com" threshold="85"  df -h | tail -n +2 | awk '{print $1 " " $5}' | sed 's/.$//' | while read i; do   part=$(echo $i | awk '{print $1}')   util=$(echo $i | awk '{print $2}')     if [ $util -ge $threshold ]; then       echo $part is ${util}% full. An email has been sent to your administrator.       mail -s "Critical: $part is ${util}% full. Clear space immeadiately!" $admin     fi done   Output:  /dev/mapper/rootvg-root is 92% full. An email has been sent to your administrator.   But, you can see /dev/mapper/rootvg-apps is also 98% full:  /dev/mapper/rootvg-apps            20G   20G  445M  98% /apps /dev/mapper/rootvg-tmp            6.0G  2.4G  3.7G  39% /tmp /dev/mapper/rootvg-var_log        6.0G   71M  6.0G   2% /var/log /dev/xvda1                        497M  142M  356M  29% /boot

I'm having issues with a script i'm writing.  I'm trying to monitor free disk space, and to have an email generated for each filesystem over a certain threshold.  When using this script with 'echo' instead of 'mail', the output looks correct to my terminal.  When i incorporate mail, only the critical warning is sent, and the body of the email includes the other filesystems.  I'm trying to send individual emails for each filesystem.  I'm not looking for an answer, but maybe a certain place to focus on to try and determine what my issue is.     #!/bin/bash     #The following script will check filesystems (local/nfs only)     #and notify via email current user if over certain threshold.      #Thresholds for script to call     CRITICAL=90     ALERT=70      #Gets local/nfs disk info, greps out header/tmp filesystems and awks column 1 and 5     #while read loop is enabled to parse through each line     df -l | grep -vE '(^Filesystem)' | awk '{ print ($5  " " $1)}' | while read output;     do         #updates variables to reads current step         usage=$( echo $output | awk '{print $1}' | cut -d'%' -f1 )         part=$( echo $output | awk '{print $2}' )          #if percentage matches alert or critical, email current user         if [ $usage -ge $CRITICAL ]; then             mail -s "Critical Warning: Filesystem $part is at $usage% of capacity." $USER         elif [ $usage -ge $ALERT ]; then             mail -s "Warning: Filesystem $part is at $usage% of capacity." $USER         fi     done


I am attempting to solve part (b) of problem 4.2 in Chapter 12 of Artin's Algebra textbook. I have already solved part (a).  Prove that the following polynomials are irreducible: (a) $x^2+1$ in $\mathbb{F}_7[x]$ (b) $x^3-9$ in $\mathbb{F}_{31}[x]$  My attempt Assume $x^3-9$ is reducible. It is easy to see that it is not a unit, so it must have a proper divisor. So we can write $x^3-9=a(x)b(x)$ for some $a,b\in \mathbb{F}_{31}[x]$ where $a,b$ are not units, hence are not constant. One of them has degree 2 and the other degree 1. WLOG assume $a$ has degree 2 and $b$ has degree 1. Then we can write $a(x)=a_0+a_1x+a_2x^2$ and $b(x)=b_0+b_1x$. Where $a_2,b_1\neq0.$ We obtain the equations  $a_0b_0=-9$ $a_0b_1+a_1b_0=0$ $a_1b_1+a_2b_0=0$ $a_2b_1=1$  Now, I would like to obtain a contradiction by playing with these four equations, but I am not sure how to do this. Please help me. I would prefer a solution which deduces a contradiction from the four equations rather than a solution using some other method. I am aware that this math problem has already been asked on stackexchange, but I do not believe that my question is a duplicate since I desire to approach the problem from a different angle.

Is $x^3-9$ irreducible over the integers mod 31?  I know that one method is to check whether it has any roots or not, but that turns out to be very tedious in this case.  So, is there any other simpler method to find it out?


There are many examples of resolving the path of a file while following symlinks, and I'd like to get the absolute path to a file without resolving symlinks.  I think this is the solutions:   ex=Path('example.txt')   abs_ex = ex.parent.resolve()/ex   Is there something I'm missing in terms of another function or argument to resolve()?  There is an answer regarding using os.path.abspath but I'm asking about pathlib in Python 3.6 or better.

Given a path such as "mydir/myfile.txt", how do I find the file's absolute path relative to the current working directory in Python? E.g. on Windows, I might end up with:  "C:/example/cwd/mydir/myfile.txt"


I used an installation CD drive to run Ubuntu.  When I booted with installation CD on restart, it gave me an option to either "try" or "install" Ubuntu. I chose install.  During the course of installation, I did not know how to partition and all, so chose Logical Volume Management, and finished the installation successfully.  I removed the CD and restarted. I assumed now the laptop will ask for my preference of Operating Systems - Ubuntu or Windows 8- but it does not! It always starts Ubuntu! Also, the boot buttons (F1,F2,etc.) don’t work while restarting the laptop  I think I have lost Windows :(   How should I proceed?

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


I am currently running into an issue trying to manipulate a 2D char array from an external function.  char* board[] = { "first\r\n", "second\r\n", "third\r\n" };   Later in the program, I want to manipulate an arbitrary single character in the array with  board[x][y] = 'A';   However when I reprint the board, the original values still persist. The desired outcome of   board[0][0] = 'A';   Should be:   Airst Second Third   However it still prints as the original "First", indicating that board's value never got changed. How do I fix this to update board's value?

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


I am trying to figure out how to make a simple function that will take 2 arguments and return a new string that will repeat the string a certain amount of times that is described in the 2nd argument.   I would like to have it return hellohellohellohellohello but it is only returning hello once.  example:   This is what I have so far, but it only returns hello once  function repeat (arg1, arg2) {     var counter = 0     while(counter < arg2)         return arg1         counter++  } repeat("hello", 5);

What is the best or most concise method for returning a string repeated an arbitrary amount of times?  The following is my best shot so far:  function repeat(s, n){     var a = [];     while(a.length < n){         a.push(s);     }     return a.join(''); }


I enjoy taking photos with my current telephoto (55-250) but I wonder if the 70-300 could be a worthwhile upgrade. As of November 2013, it would be around a $350 investment if I deal hunt and sell my current lens.  I believe that I would benefit from the USM, for achieving focus quikcly as I am usually shooting moving subjects and my current lens is a bit slow.  How can I assess if the upgrade would be worthwhile? What improvements I could expect (with regard to quality of the pictures, AF, quietness, build quality....) stepping up to the 70-300 lens? Are there any downsides to consider?

Should I buy a Canon 55-250mm lens or 70-300mm for my Rebel T3i? I have the basic 18-55mm lens that came with my camera but I need a next step up that's not too expensive.   What are the most common types of photos shot with either lenses? Or what is each lens best for?


is an infinite sum of fractions, meaning we are dealing with rational numbers everywhere in it. If you start to approximate π (π over 4) by calculating the partial sums of the formula, you can keep using fractions - it's all just the matter of finding the least common multiple of the denominators and thus expanding the fractions.  The approximation goes like 1, 2/3, 13/15, 76/105, ...  Theoretically, you can repeat this fraction expansion infinite number of times. And no matter how long you're doing it, you will always get a rational number.   But if you never stop, you do it all the way down to infinity, the result is π over 4, which is insanely irrational. What is the point where (and the reason why) this rational pattern breaks?

Just a curiosity. I just saw a video where pi was being calculated by the series  $$1-(1/3)+(1/5)-(1/7)+...$$  My question is how can $\pi$ be irrational if we can calculate it using rational numbers?


I've written a simple CSS stylesheet that is meant to alter a page's background colour however, I'm having trouble calling it via Javascript through my HTML file. I know how to alter the background of an HTML file using Javascript, but the problem is that I don't know how to call on a stylesheet to alter the HTML file. Here's my code:  HTML
Altering style of first paragraph via Javascript.

Altering style of second paragraph via Javascript.
        Stylesheet  body {   background-color: green; }

Is it possible to import css stylesheets into a html page using Javascript? If so, how can it be done?  P.S the javascript will be hosted on my site, but I want users to be able to put in the <head> tag of their website, and it should be able to import a css file hosted on my server into the current web page. (both the css file and the javascript file will be hosted on my server).


I was configuring my navigation recently and came across this thought and I'm not sure I understand the grammatical rules as to why it is proper to say "Drive Home" but not "Drive to Home". It seems to make sense to say "Drive to My Home" but certainly not "Drive My Home".  Likewise, why is it "Drive to Work" but not "Drive Work" (aside from the obvious different meaning). I get that "Go Work" is different here since Work is also a verb, but "Go to Home" doesn't sound right.  It makes sense to me that "to" should be required as a preposition to a destination, but what makes "Home" different?

All the dictionaries I've consulted say that 'home' is an adverb and a noun, depending on context. For example:  (1) He went home. [adverb] (2) He is at home. [noun]  Also, there's  that seemingly resolves the issue of why 'home' sometimes should be analyzed as an adverb. But what about this example?  (3) I can find my way home.  Can you also say that home in (3) is an adverb? It seems to me that home in (3) cannot be an adverb, because I think it functions as a complement of the noun way and that my way home as a whole is a noun phrase. Even if we accept John Lawler's analysis in the above quoted answer of considering home "one of those idiomatic locative nouns that are allowed to drop determiners and occasionally even prepositions," we cannot say home in (3) is an example of "how a noun can be used as an adverb", because (3) can be analyzed as John Lawler suggests:  (3') I can find my way (to my) home.  Here, to my home is not an adverbial prepositional phrase but an adjectival prepositional phrase that acts as a complement of the noun way. So, to take what John Lawler said and adapt it to (3), "what it is is an [adjectival] prepositional phrase that has been stripped of its prepositions and determiners, leaving only a naked noun to stand for the whole phrase. That's how a noun can be used as an [adjective]." Now, does this mean we should call home a noun, an adverb, or an adjective, depending on context?


So we were learning implicit differentiation a couple of months ago, and I noticed that while for some equations, like ${{x}\over{y}}=1$ can easily be rewritten as $y=x$ and therefore have a very easy derivative to take, some equations, especially those that broke the vertical line rule, were very hard to convert to explicit.  For example, the equation of a circle, $x^2 +y^2=r^2$ can be rewritten as $y=\pm \sqrt{r^2-x^2}$, so my question is: can all implicit formulas be rewritten as one or more explicit equations? If yes, how do we know, but if not, could you provide a counterexample?  Please try to simplify your answers so a high-schooler could get it, but I'll try my best to understand each answer.

What is the general reason for functions which can only be defined implicitly?   Is this because they are multivalued (in which case they aren't strictly functions at all)?   Is there a proof?   Clarification of question.  The second part has been answered with example of single value function which cannot be given explicitly. The third part was automatically answered because there can't be a proof that necessarily implicit functions are all multivalued by way of the example of one that wasn't.    I don't think that the first part has yet been addressed. Stating that the answer can't be expressed in "elementary functions" seems tantamount to saying that it a necessarily implicit function, unless I'm missing something about the definition of "elementary functions". Such answers seem to imply that the equation could be solved in terms of "non-elementary" functions.If this is correct than I need to find out about them and how they could be used to calculate the dependent variable solely in terms of the independent one (my notion of an explicit function). This would seem to violate the notion of a function which could only be defined implicitly. I am also not concerned with whether or not the solution is closed or open form (by which I mean finite number of terms or infinite).