What are the downsides (if any) of having a PhD to work in the software industry? Any about having technology certifications?

So you can take me seriously, let me first introduce myself: I am a PhD student about to finish my thesis and, thinking about future employment, I am considering to obtain an Oracle Java Certification, ammong other things.  The question I ask may sound odd, but I found this comic:   Apparently, having a PhD is considered as a downside when applying for a job in the software industry. I don't see how that may be funny, and the reason behind it.   Moreover, and actually what made me make this question here: having taken a course in a technology is considered much worse, for instance, than having grammar errors in the resume or mentioning your skills using MS Word. One guy even say "The point about certifications is dead-on". Other person comments "For most of the good Cisco certifications you HAVE to take the course, otherwise you will epic fail".   This make me wonder if the problem is to had taken the course to get the certification, not the certification itself. Maybe they mean that showing in your CV that you completed a 10 hours online course on "Starting with C language" is perhaps not a good idea. Otherwise I don't understand.   I hope someone can shed some light on this.


Total noob question, but the passive perception is confusing. I don't understand how to calculate it or use it, and I need help.


I was trying to install Electron using NPM, and this showed up:  adi@LMToshi2 ~ $ npm install electron --save-dev --save-exact npm ERR! Linux 4.8.0-53-generic npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install" "electron" "- -save-dev" "--save-exact" npm ERR! node v4.2.6 npm ERR! npm  v3.5.2 npm ERR! code ECONNRESET npm ERR! errno ECONNRESET npm ERR! syscall read  npm ERR! network read ECONNRESET npm ERR! network This is most likely not a problem with npm itself npm ERR! network and is related to network connectivity. npm ERR! network In most cases you are behind a proxy or have bad network settings. npm ERR! network  npm ERR! network If you are behind a proxy, please make sure that the npm ERR! network 'proxy' config is set properly.  See: 'npm help config' npm ERR! Linux 4.8.0-53-generic npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install" "electron" "--save-dev" "--save-exact" npm ERR! node v4.2.6 npm ERR! npm  v3.5.2 npm ERR! code ECONNRESET npm ERR! errno ECONNRESET npm ERR! syscall read  npm ERR! network read ECONNRESET npm ERR! network This is most likely not a problem with npm itself npm ERR! network and is related to network connectivity. npm ERR! network In most cases you are behind a proxy or have bad network settings. npm ERR! network  npm ERR! network If you are behind a proxy, please make sure that the npm ERR! network 'proxy' config is set properly.  See: 'npm help config' npm ERR! Linux 4.8.0-53-generic npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install" "electron" "--save-dev" "--save-exact" npm ERR! node v4.2.6 npm ERR! npm  v3.5.2 npm ERR! code ECONNRESET npm ERR! errno ECONNRESET npm ERR! syscall read  npm ERR! network read ECONNRESET npm ERR! network This is most likely not a problem with npm itself npm ERR! network and is related to network connectivity. npm ERR! network In most cases you are behind a proxy or have bad network settings. npm ERR! network  npm ERR! network If you are behind a proxy, please make sure that the npm ERR! network 'proxy' config is set properly.  See: 'npm help config' WARN engine hawk@6.0.2: wanted: {"node":">=4.5.0"} (current: {"node":"4.2.6","npm":"3.5.2"})   BTW: I am not in a Proxy.


Confused about the electric field at the surface of a conductor

We know that the electric field at the surface of a conductor only have a normal component equal to $\rho/\varepsilon$ (finite number).  But let’s consider the point $\text{P}$ (at the surface of a conductor). Assume that there is a charge at an infinitesimal distance from the point $\text{p}$. We can obtain the field at the $\text{P}$ by the formula $E=Kq/r$. Obviously, $E\sim1/r$. So the normal component of the field is infinite. Now if we add the field due to other charges, it will remain infinite. So where could I be possibly wrong?


I know base 2 and base 10 , MB and MiB, but i'm not understanding the byte counts shown for a directory, by du and by windows explorer

The du command shows 43G in use. I'm not sure whether that's base 2 in the sense of 2^30 or if it's base 10, in the sense of 10^9.  But anyhow -   Running this du command from cygwin, to see the size of the windows directory (done from an administrative command prompt - since it seemed to have some issues reading some directories otherwise)  user@comp ~ $ du -sh /cygdrive/c/windows 43G     /cygdrive/c/windows   Windows Explorer  which I understand shows it in 'base 2', (a larger unit for KB,MB,GB than base 10 KiB, MiB e.t.c.), and hence a lower quantity of that larger unit is required to give the same result.    Windows explorer shows      46.6GB  , over 50 billion bytes.    (according to windows explorer)  or  46.8GB  , over 50 billion bytes. (according to windows explorer)  So, du aside.  Even if I multiply the larger figure, 46.8GB  by 1.048576 then I get 49.0733568 that's not over 50 billion. So that's part A of the question,  but then also, part B of the question, why is the du figure so low.


More than one version of my site is indexed, is this normal?

SSL cert is set to force HTTPS - but i can’t seem to set it so the only version that is accessible is secure WWW version.  I’ve added all 4 versions to search console. I also submitted a sitemap for each. I noticed both versions of home page are in search. Should only one version be indexed? Should I have submit a sitemap for each version? I already set www as preferred version. What is best practice?    I’ve been reading for,hours,I can’t figure out what is the best practice proper way.


Let $A$ be an $n \times n$ matrix for which $A^k = 0$ for some $k > n$. Show that $A^n = 0$.

I have a problem getting this started. Can anyone help?     Let $A$ be an $n \times n$ matrix for which $A^k=0$ for some $k>n$. Show that $A^n=0$.


Why does "ls -all" show time for some files but only year for others?

If you issue ls -all command some files or directories have the year and some have the time? Why do some show the year while others show the time? Is the time representative of the time the file was created?


find the limits : $\lim_{n}( \frac{1\cdot3\cdot5\cdot \cdot \cdot(2n-1)}{2\cdot4\cdot6 \cdot \cdot \cdot (2n)} ) =?$

Find the limits (without Stirling's approximation ) : $$\lim_{n}( \frac{1\cdot3\cdot5\cdot \cdot \cdot(2n-1)}{2\cdot4\cdot6 \cdot \cdot \cdot (2n)} ) =?$$   My Try : $$\frac{1\times 3\times 5\cdots \times(2n-1)}{2\times 4\times 6\cdots \times(2n)}=\frac{(2n)!}{4^n(n!)^2}$$ now what ?


I need the combination for it and can't find it any where. I have looked everywhere I can think of.


Add JavaScript and jQuery to SharePoint in one page

I open My Editform.aspx page with SharePoint Designer and I want to add javascript code to it. This is the code:      <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <script> $(document).ready(function(){   $("#a").click(function(){     $("#content").hide();   });   $("#b").click(function(){     $("#content").show();   }); }); </script>   How can I add and place  it to one SharePoint page?


Copy ubuntu.iso to Usb Stick with two partitions

This question is different from the one marked as duplicate as I know how    to install Ubuntu on an USB Key but I want to have an additional partition on this USB Key    I have an USB 3.0 Stick with 64GB and I want to use it to save some backup data in an encrypted Partition but also have one partition with a bootable ubuntu.   Making a bootable ubuntu stick is easy:  # sudo dd if=ubuntu-16.04.2-desktop-amd64.iso of=/dev/sdX bs=1k count=2048 conv=fdatasync   (changed sdd to sdX to prevent users from copying it and harm their system)  But then I get a strange partition table:   # fdisk -l /dev/sdd Medium /dev/sdd: 58,4 GiB, 62746787840 Bytes, 122552320 Sektoren Einheiten: sectors von 1 * 512 = 512 Bytes Sektorengröße (logisch/physisch): 512 Bytes / 512 Bytes I/O Größe (minimal/optimal): 512 Bytes / 512 Bytes Typ der Medienbezeichnung: dos Medienkennung: 0x15e2543d  Gerät      Boot Start    Ende Sektoren Größe Id Typ /dev/sdd1  *        0 3035519  3035520  1,5G  0 Leer /dev/sdd2       14432   19295     4864  2,4M ef EFI (FAT-12/16/32)   This seems to be correct as my stick is booting fine. But I really don't understand it.   When I partion the usb device before and have one FAT32 and one LUKS parttion then I still can dd the iso to the first partition /dev/sdd1 but it is not bootable anymore.   I set the bootable flag on the first partition of course an my laptop tries to boot it but only shows a blinking underscore.   There are so many misleading informations in the web about this scenario. I am lost. I am familiar with partitioning, and MBR and GRUB but only in using it. It seems I never really understood what is going on and many things have changed since I last did it (EFI, loop devices..)   It seems to be very difficult to use an USB stick as a bootable ubuntu AND as a backup partition. But I still think this should be a matter of   Formatting and partitioning USB stick Copying ISO to partition Make some magic like MBR, bootable flag, Grub2   Can somebody help with a small step-by-step command line example to get things running on a modern ubuntu 16.04?  The second partition doesn't need to be mounted on Windows by the way.


How could the Death Eaters Apparate straight to Voldemort without knowing where he is?

In this question, I am speaking mostly about the first time Voldemort calls them after being reconstituted at the end of Goblet of Fire. Here, there is no indication that they had been informed that Voldemort would be at the graveyard in advance (indeed, no one knew that he was back in Britain save for Peter Pettigrew and Barty Crouch Jr).   We know that Death Eaters can be contacted by Voldemort through the Dark Mark tattoo on their arms. Once they feel the 'call', they are to Disapparate and Apparate immediately to him. But since they need to know the 'destination' (one of the "Three D's" of Apparition), how are they able reach him without knowing the location of where he was?   Is there an explanation for this related to the Dark Mark 'tattoo contact spell' (my ineloquent term for it)? Is there some other power alluded to elsewhere in the series?  I think the question matters, because if they were able to find and reach Voldemort through Apparition, without precise knowledge of the location/destination (i.e. exactly where Voldemort is), why couldn't the Death Eaters do the same when trying to find Harry (or anyone), especially in Deathly Hallows, when Harry was over 17 and away from Hogwarts and other forms of protection? And conversely, why couldn't the Ministry, Aurors, members of the Order of the Phoenix or anyone Apparate to find Voldemort and capture him?


I opened the PC in the morning, and this is what I got:      As is visible the icons of the UWA apps were no affected and the start menu also is unaffected.    When Control Panel is in category view the entire page is empty and in large/small icons the name is visible, no icons.  I deleted the iconcache.db in %USERPROFILE%\AppData\Local folder. Following the instructions here: . But to no avail and now windows is not rebuilding the cache.   I also ran sfc /scannow but no changes took place.  What should I do?  (01/01/2016 8:00PM GMT +5:30) Edit: I tried opening the system properties and I got 0x8000ffff error and this:        Then I closed the popup and pressed the OK button on the System Properties Windows and I got 0x8007057A error:      Opening the Image Backup Control Panel page I again got an 0x8007000E error:        I tried using system restore via advanced startup but once again I got 0x800FFFF error.  P.S.: I did try restarting, didn't work.


Proof of correctness of a homomorphic ElGamal sum

Let's suppose we are using the exponential ElGamal as a public-key encryption scheme, so that we encrypt $g^m$ instead of $m$, for some generator $g$. Let $x$ be the private key, and $h=g^x$ be the public key.   We have two parties, and each one of them has a ciphertext encrypted with the same public key: $(R_1,S_1)=(g^{r_1}, g^{m_1} h^{r_1})$ and $(R_2,S_2)=(g^{r_2}, g^{m_2} h^{r_2})$, respectively.  These two parties then gather and perform the homomorphic sum of their ciphertexts by computing the product of their ciphertexts: $(R_3,S_3) = (R_1,S_1) \cdot (R_2, S_2) = (g^{r_1+r_2}, g^{m_1+m_2} h^{r_1+r_2})$.  Is there any way they can prove in zero-knowledge that the sum is correct? That is to say, that $(R_3,S_3)$ is the correct encryption of $m_1+m_2$ without revealing anything else about the addends ($m_1$ and $m_2$ should be kept secret) nor the (plaintext) value $m_1+m_2$?


I'm googling for this, but the terms are so generic I'm getting way too many false positives, so what the hey, I'll ask here.  I'm sure there's a simple answer but I don't generally script in *nix.  I'm trying to write a database refresh script to our test environment.  The backups are mounted from an smbfs share, something like /data/backups/prod, but the subfolders get a little tricky.  It looks like myproddbserver/yyyymmdd, with a bunch of files underneath.  I want to execute a command restore that will collect the files with known names from the most recent yyyymmdd directory.  For example, if I had:  myproddbserver/20130630/foo.bak myproddbserver/20130630/bar.bak myproddbserver/20130731/foo.bak myproddbserver/20130731/bar.bak   I would want to restore myproddbserver/20130731/foo.bak and myproddbserver/20130731/bar.bak.  How would I reliably get those paths?


I have a bunch of metallic materials that use the Principled BDSF, and I need to change all of them from a metallic value of 10 to a metallic value of 1. Can this be done using a script?


If $\alpha_1,\alpha_2,\ldots,\alpha_n$ be the roots of the equation $x^n+1$

then $(1-\alpha_1)(1-\alpha_2)\ldots(1-\alpha_n)$ equals to ? I think here we need the info of whether $n$ is even or odd else how will we say whether by vieta's formula what is the value of $1+(-1)^n$ ?


Can someone tell me why I dont have the coordinate slots? I have a screenshot of it.


C:\Program Files folder equivalent on Ubuntu

Which folder in Ubuntu is equivalent to C:\Program Files like on windows? Where are all programs installed?  when i type   apt-get install leafpad   or  sudo apt-get install sublime-text-installer   Where do they go??? Which folder?


Find: $\lim_{x\to -\infty} \frac{\ln (1+e^x)}{x}$ (no L'Hospital)

Find: $\displaystyle \lim_{x\to -\infty} \dfrac{\ln (1+e^x)}{x}$ (no L'Hospital)   I'm getting a hard time solving this limit. The book shows 1 as the answer, Wolfram Alpha shows 0.   I could solve easily another problem when the denominator was $e^x$ but got stuck on this one.   No L'Hospital rule can be used.  Hints and full answers are appreciated. Sorry if this is a duplicate.


NullPointerException even when 0th index has a value

This is the main class:-  import javax.swing.JFrame;  public class RR {     public static void main(String[] args) {         RegionalResource object = new RegionalResource();         object.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);          object.setSize(500,500);         object.setVisible(true);     } }   Here's the other class:-  import java.awt.*; import java.awt.event.*; import javax.swing.*;  public class RegionalResource extends JFrame {     private JComboBox box;     private JLabel picture;      private static String imagenames[] = {"1.png", "2.png"};     private Icon images[] = {new ImageIcon(getClass().getResource(imagenames[0])), new ImageIcon(getClass().getResource(imagenames[1])) };      public RegionalResource() {          super("Tourism Information Provider");         setLayout(new FlowLayout());          box = new JComboBox(imagenames);          box.addItemListener(                 new ItemListener() {                     public void itemStateChanged(ItemEvent event) {                         if(event.getStateChange() == ItemEvent.SELECTED)                         {                             picture.setIcon(images[box.getSelectedIndex()]);                         }                     }                 }             );         add(box);         picture = new JLabel(images[0]);         add(picture);     } }   When I run the program (in eclipse oxygen 2), it results in the following error  Exception in thread "main" java.lang.NullPointerException  at javax.swing.ImageIcon.<init>(Unknown Source) at RegionalResource.<init>(RegionalResource.java:11)  at RR.main(RR.java:6)


Very slow compile times on Visual Studio 2005

We are getting very slow compile times, which can take upwards of 20+ minutes on dual core   2GHz, 2G Ram machines.  A lot of this is due to the size of our solution which has grown to 70+ projects, as well as VSS which is a bottle neck in itself when you have a lot of files. (swapping out VSS is not an option unfortunately, so I don't want this to descend into a VSS bash)  We are looking at merging projects.  We are also looking at having multiple solutions to achieve greater separation of concerns and quicker compile times for each element of the application. This I can see will become a DLL hell as we try to keep things in synch.  I am interested to know how other teams have dealt with this scaling issue, what do you do when your code base reaches a critical mass that you are wasting half the day watching the status bar deliver compile messages.  UPDATE I neglected to mention this is a C# solution. Thanks for all the C++ suggestions, but it's been a few years since I've had to worry about headers.  EDIT:  Nice suggestions that have helped so far (not saying there aren't other nice suggestions below, just what has helped)   New 3GHz laptop - the power of lost utilization works wonders when whinging to management Disable Anti Virus during compile 'Disconnecting' from VSS (actually the network) during compile - I may get us to remove VS-VSS integration altogether and stick to using the VSS UI   Still not rip-snorting through a compile, but every bit helps.  Orion did mention in a comment that generics may have a play also. From my tests there does appear to be a minimal performance hit, but not high enough to sure - compile times can be inconsistent due to disc activity. Due to time limitations, my tests didn't include as many Generics, or as much code, as would appear in live system, so that may accumulate. I wouldn't avoid using generics where they are supposed to be used, just for compile time performance  WORKAROUND  We are testing the practice of building new areas of the application in new solutions, importing in the latest dlls as required, them integrating them into the larger solution when we are happy with them.  We may also do them same to existing code by creating temporary solutions that just encapsulate the areas we need to work on, and throwing them away after reintegrating the code. We need to weigh up the time it will take to reintegrate this code against the time we gain by not having Rip Van Winkle like experiences with rapid recompiling during development.


Why energy at room temperature $= kT$ and not $(3/2)kT$

I always see that a room temperature of $T=300\,\text{K}$ corresponds to an energy of $k_BT \approx \frac{1}{40}\,\text{eV}$. But shouldn't it be $\frac{3}{2}k_BT$ since the molecules in the air have three degrees of freedom for translation and not two? Is there a deeper meaning to neglect the $3/2$?


Remove grey outline from Lightning component

I have created a lightning component which sits as an Action in my Service Console like this...    I am trying to remove the grey outline inside the box, I have tried setting CSS styles on the lightning card but it doesn't work.  <aura:component implements="force:lightningQuickActionWithoutHeader,force:hasRecordId">      <lightning:card title="Send customer a text message" class="testclass">
             <lightning:input type="text" name="myNumber" aura:id="number" value="{!v.simpleRecord.CaseNumber}" label="Customer Number" class="slds-m-bottom_xx-small"/>             <lightning:textarea name="yourMessage" aura:id="message" label="Your message" required="true"/>
             <lightning:button label="Send" iconName="utility:sms" iconPosition="right" variant="brand" onclick="{!c.onSubmit}" />
     </lightning:card>  </aura:component>   Style  .THIS {     background-color: #fff; }  .THIS .testclass {     background-color: red; }   Can someone tell me how I can make the entire background white?


Is $\mathbb{R}^4$ minus a line simply connected?

Is the set $\mathbb{R}^4\setminus \{(0,0,0,w)  | w\in \mathbb{R} \}$ simply connected? I started trying to grasp the notion of simple connectedness in higher dimensions and realized I could not even a figure out such a basic question.   My intuition says it is not simply connected but maybe you can twist things around in 4 dimensions in ways I can not visualize.


Work done by gravity on falling object does not seem to equal change in mechanical energy

So I have some confusion here, I am sure I knew this at some point.  Let's say an object of 10 kg is dropped from a height of 10 m.  When it reaches the ground, the work done on the object should be the force ($mg$) x distance or 10 kg x 9.8 m/s/s x 10 m.  That gives 980 joules of work done on the object by gravity.  But the object did not gain 980 joules of .  It lost 980 joules of GPE and gained 980 joules of kinetic energy (up to the point of it reaching ground level).   Using the change in GPE and KE, it looks like no work was done on the object because the loss in GPE equals the gain in KE.  So   a) am I right that no net work was done on the car by sum of all forces?    b) is the work done by gravity equal to force time distance, or is it equal to the change in mechanical energy of the object which is zero?


TL;DR: The Windows 10 upgrade icon went missing. How do I get it back in order to update my system? I am running Windows 7 SP1.   I woke up this morning... er, noon all excited about Windows 10. I had reserved my copy using the clever little icon in the taskbar a few weeks back, so I thought I would be set to go. I booted my computer and checked the icon to see if it would download the update. It still behaved the same as if Windows 10 wasn't launched yet. I supposed this was normal behaviour. After all, Microsoft can't roll out the update to everyone at once.   Windows Update did want me to install several updates though. I installed KB2952664, KB3064209 and KB3048761. Everything went fine, and I was prompted to restart my system.   After restarting, the icon wasn't there anymore. I tried a lot of solutions including the answers provided by our awesome community on , and the answer provided to  posted on the Microsoft Windows support forums.   How do I get the icon back in order to update my system?  UPDATES:   Installing from the Media Creation Tool does not working with an error "Something Happened" with as description "Something Happened". Both are translated from Dutch.  I tried to install it from the Media Creation Tool using PowerISO to mount the created ISO. It will not accept my product key, even though I am able to verify my Windows installation is already registered and the product key is correct. I looked into the Event Log, and GWX-Ins has a bunch of error messages saying: Error message: GWX Main: App failed to start hresult. After that it says what is roughly translated to English as "Cannot find the element".


How do I convert a TimeSpan to a formatted string?

I have two DateTime vars, beginTime and endTime. I have gotten the difference of them by doing the following:  TimeSpan dateDifference = endTime.Subtract(beginTime);   How can I now return a string of this in hh hrs, mm mins, ss secs format using C#.  If the difference was 00:06:32.4458750  It should return this 00 hrs, 06 mins, 32 secs


Non-hermitian hamiltonians and symmetry properties of $\partial_t$

From  another one came to my mind. Consider the Hilbert space $\mathcal{H}$ of function square integrables $\psi:\mathbb{R}^n\rightarrow\mathbb{C}$ with the usual inner product:  $$ \langle\psi,\chi\rangle = \int_\mathbb{R} d^n\!x\psi^*\chi\quad\mbox{ and }\quad\psi\in\mathcal{H}\Rightarrow\langle\psi,\psi\rangle\in\mathbb{R}, $$  where $\psi^*$ is the complex conjugate of $\psi$. I am thinking in particular in two-variable functions $\psi(x,t)$, but the generalisation to more spatial dimensions is straightforward. Given an operator $A$, the hermitian conjugate $A^\dagger$ saisfies $\langle\psi,A\chi\rangle = \langle A^\dagger\psi,\chi\rangle\,\forall\psi\chi\in\mathcal{H}$.   Take $A=i\partial_t$, hence:  $$ \langle\psi,A\chi\rangle = i\int dx\int dt\psi^*\partial_t\chi = -i\int dx\int dt\partial_t(\psi^*)\chi = \int dx\int dt(i\partial_t\psi)^*\chi = \langle A\psi,\chi\rangle $$ iwhere in the second steps I integrated by parts and dropped the global derivative assuming suitable boundary conditions, and in the third equality I used $(\partial_t\psi)^*=\partial_t(\psi^*)$. Then $A = A^\dagger$.  But since $A\psi =i\partial_t\psi = H\psi$ from the Schrödinger equation, doesn't it imply that the Hamiltonian must be always Hermitic?.


Why is the set of commutators not a subgroup?

I was surprised to see that one talks about the subgroup generated by the commutators, because I thought the commutators would form a subgroup. Some research told me that it's because commutators are not necessarily closed under product (books by Rotman and Mac Lane popped up in a google search telling me). However, I couldn't find an actual example of this. What is one? The books on google books made it seem like an actual example is hard to explain.   Wikipedia did mention that the product $[a,b][c,d]$ on the free group on $a,b,c,d$ is an example. But why? I know this product is $aba^{-1}b^{-1}cdc^{-1}d^{-1}$, but why is that not a commutator in this group?


Web sites do not work when I am logged into Google Chrome or need to log in to Google

This problem is really weird. If I log into Google chrome, I can not use Google to search. And I cant log in to sites like this one and Stack Overflow with my Google account. The pages time out with "no response from server" type errors.  If I use a Windows PC on the same network it is fine, but in Ubuntu or Mint it fails.  The problem started a month ago so I switched from Mint to Ubuntu with no improvement.   When I search Google (not logged into Chrome) the results pages are usable. But if I log into Chrome, I get a page of results that I can't click on unless I manually change the link. For example this link:    Fails to redirect, but if I open in a new tab and change the google.co.nz/ to google.com/ it will load.  DNS lookups are working fine using dig or nslookup to confirm.  Does any one have a clue as to what to try next? This a now a fresh install of Ubuntu 13.10, but had the exact same problem on Mint and a Windows PC works fine (how I am logged in now).


Fantasy (audio)book about boy being recruited

I'm looking for a book (well, an audiobook) that I listened to maybe 7, 8 years ago in English (I live in the U.S.), and for young children, or maybe for teens. My memory is very shaky but here goes:  I remember a boy and his friends entering a competition. I don't remember what the competition was for, but I remember the first stage being some sort of space game or something with each team having a certain target (so sort of like the Assassin game), and the main character eliminated his friends. One of the spaceships had an ability to become invisible, if I remember correctly.  I remember the boy was (intentionally, I think) harpooned by another person competing with him relatively late-stage. The kids/teens were divided into 2 groups and were competing for something, and all had harpoons.  I remember the boy and another boy having to compete by rolling a marble/ball through a maze telekinetically, and the main character barely won by choosing a faster path, despite not being able to roll the marble as fast.  I remember the boy and a girl going into another part of the world that was previously unknown to them (and was sectioned off or something).


When the trace of the Frobenius homomorphism is zero?

Let's consider an elliptic curve over a finite field $\mathbb F_p$.  The trace of the Frobenius homomorphism is defined as:  $$a_p=p+1-\#E(\mathbb F_p)$$  See for example .  I read that this value is zero if and only if the elliptic curve is supersingular. Unfortunately there is no proof give. So I am looking for a proof of this. (For example a good reference).


Where were the locations of the districts in The Hunger Games?

In , the nation of Panem (implied to be North America after some sort of post apocalyptic scenario) is divided into 13 districts and the Capitol. District 12 is hinted to be in the Appalachia Mountains, and the Capitol is hinted to be in the Rocky Mountains. District 13, which was destroyed, is described as "east of District 12", which made me think it's where Washington D.C. is today.  The other districts, however, were mostly ignored, and almost no detail was provided as to their locations in the books. Has there been any supplemental information that reveals where the districts are?


I've been learning Lisp to expand my horizons because I have heard that it is used in AI programming. After doing some exploring, I have yet to find AI examples or anything in the language that would make it more inclined towards it.  Was Lisp used in the past because it was available, or is there something that I'm just missing?


Problem with making raster from Aspect and wind direction data

I know its not correct to ask for work flow, but I am learning by doing and now I don't know how to move on.  I'm trying to make new raster which will represent the facing sides of hill around a factory. Then I'll use wind data (.csv) file to get which of these sides are more often under blowing wind. Wind data are for 10years, and the average is north-west flow.  I was looking for some index but I couldn't find one. So is there any chance to make it with the QGIS raster calculator?


Prove that $\frac{b+c}{\sqrt{a}}+\frac{c+a}{\sqrt{b}}+\frac{a+b}{\sqrt{c}} \geq \sqrt{a}+\sqrt{b}+\sqrt{c}$

If $a,b,c$ are positive reals and $abc=1$, Prove that $$\frac{b+c}{\sqrt{a}}+\frac{c+a}{\sqrt{b}}+\frac{a+b}{\sqrt{c}} \geq \sqrt{a}+\sqrt{b}+\sqrt{c}$$  My try: $$\frac{b+c}{\sqrt{a}}+\frac{c+a}{\sqrt{b}}+\frac{a+b}{\sqrt{c}}=\frac{b+c+a-a}{\sqrt{a}}+\frac{c+a+b-b}{\sqrt{b}}+\frac{a+b+c-c}{\sqrt{c}}$$ $\implies$ $$\frac{b+c}{\sqrt{a}}+\frac{c+a}{\sqrt{b}}+\frac{a+b}{\sqrt{c}}=(a+b+c)(\frac{1}{\sqrt{a}}+\frac{1}{\sqrt{b}}+\frac{1}{\sqrt{c}})-(\sqrt{a}+\sqrt{b}+\sqrt{c})$$ Is there a way from here?


Why can the forbidden corridor on the third floor be unlocked by simply using Alohomora?

If that corridor's just so important and held a very dangerous beast, why would they let it be opened just by simply casting an Alohomora?


Is it standard for graduate students to get gifts for their advisors?

Is it standard for graduate students to give their advisors gifts around Christmas, like chocolates or bottles of wine?  What about other important people, such as their thesis committee members, or department secretaries?


I'm cleaning up my MBP and found two Library folders, one of 3.37 Gb and the other 9.75 Gb. Why are there two of them, and more importantly, how can I reduce their sizes?


Can someone show me a straightforward proof that  $\lim_{m\to\infty}(1+\frac{r}{m})^{mt}=e^{rt}$  Thanks!


UBUNTU 14.04 cheese booth not detect webcam

Cheese Booth shows an error:     There was an error playing video from the webcam     I test if webcam works fine or not by opening google hangout, its works fine.    Please tell, what is the issue in cheese booth.  Note: Sometimes the cheese booth works fine but most of time not


What does the number on the favorites tab mean?

I went to my user page this weekend and was surpised to see this:    I only have 11 questions favorited, so I thought that 34 seemed a bit high.  Then I realized that I actually have no idea what that number means.  I found an awesome answer by  to this question:    But, his observations ("The number next to the tab indicates how many posts have new answers since you last visited the tab") do not match up with what I'm seeing:     I don't have 34 questions favorited, so I don't think it's a count of questions with new answers It doesn't seem to be a tally of all the new answers on my favorited questions either (because there are only 32 answers total to those 11 questions).   Could we get a clear definition of what this number means?  This is obviously not a high-priority request, I'm just curious =)  I have left  the same for now, in case that is helpful to anyone doing detective work on this feature =)


Are there any worthwhile benefits to saving Cid in the World of Ruin?

I've been reading that it is possible to keep Cid alive after Celes wakes up from you coma on Solitary Island in Final Fantasy VI, from what I've read if I end up saving Cid, instead of Celes finding out about the raft from Cid's note he shows it to her himself  Considering that there are only 2 good fish that will raise Cid's health, his health drops by 1 every second your not in a menu, you can let it drop bellow 30 and have to raise it above 255 to save him it seems like a hell lot of work and I've always thought that after Cid's death and Celes's attempted suicide due to her now being left alone in the world made for a better motivation for her to search for Locke after seeing that bird.  So i'm wondering, apart from the slight change in how he finds the raft to leave the island, is there any worth while changes what would validate spending so much time trying to save Cid cause i remember spending 10 minutes getting fish repeatedly to get nowhere so I just then waited


I am preparing to teach an enrichment session to some 16 year olds, about Continued Fractions. I am confused about the following paradox.  1=2 via Continued Fractions This is true of course that $1=\frac{2}{3-1}.$ Now, let's substitute this very expression for $1$ in the denominator: $$1=\frac{2}{3-\frac{2}{3-1}}.$$ We can do that one more time: $$1=\frac{2}{3-\frac{2}{3-\frac{2}{3-1}}}.$$ And one more time to make sure there is no misunderstanding of the construction, $$1=\frac{2}{3-\frac{2}{3-\frac{2}{3-\frac{2}{3-1}}}}.$$ At this point I am assuming that further steps could be performed by any reader who got this far. To indicate that possibility I'll use the ellipsis: $$1=\frac{2}{3-\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}}.$$ Well, we also know that $2=\frac{2}{3-2}.$ With this as a starting point, we follow in the footsteps of the previous example. Replacing $2$ in the denominator with that expression gives $$2=\frac{2}{3-\frac{2}{3-2}}.$$ To continue as before: $$2=\frac{2}{3-\frac{2}{3-\frac{2}{3-\frac{2}{3-2}}}}.$$ And finally, $$2=\frac{2}{3-\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}}.$$ But this is exatly the same continued fraction. By necessity we conclude that $1=2.$ — by 24.0.94.225 at 20110927 via   What is the hole in the argument? Presumably it has something to do with lack of convergence, but would anyone be able to explain it so that:  I could undersatnd it (I studied Maths at university)  16 year olds (with no formal knowledge of analysis or the language of convergence) would understand it?   Thank you.


Can anyone tell me what I'm doing wrong here? Command block said:     Data tag parsing failed: Unbalanced Quotation:   I am creating a sign in Minecraft with multiple colors on a single line. The only thing I need is to execute a command upon right-click of the sign. I got the colors and everything working fine. I'm pretty new to this though, so sorry if I'm just missing a quote or something. ;)  This one works, I just need to add a click event:  /give @p sign 1 0 {BlockEntityTag:{Text2:"[\"\",{\"text\":\"[\",\"color\":\"gold\"},{\"text\":\"Assault\",\"color\":\"gray\"},{\"text\":\"]\",\"color\":\"gold\"},{\"text\":\"\",\"color\":\"dark_aqua\"}]",Text3:"[\"\",{\"text\":\"(Right-Click)\",\"color\":\"dark_gray\"}]",Text4:"[\"\",{\"text\":\"\",\"color\":\"\"}]",id:"Sign"}}   Like so:  clickEvent:{action:run_command, value:\"/tp @p 1027 62 1000 \"}   Here is the command that gave me the error:  /give @p sign 1 0 {BlockEntityTag:{Text2:"[\"\",{\"text\":\"[\",\"color\":\"gold\"},{\"text\":\"Assault\",\"color\":\"gray\"},{\"text\":\"]\",\"color\":\"gold\"},{\"text\":\"\",\"color\":\"dark_aqua\"}]",Text3:"[\"\",{\"text\":\"(Right-Click)\",\"color\":\"dark_gray\"}]",Text4:"[\"\",{\"text\":\"\",color\":\"blue\"}],id:"Sign",clickEvent:{action:run_command, value:\"/tp @p 1027 62 1000 \"}}


Increase in the size of nested parenthesis with \left and \right

I want to obtain an increase in the size of nested parenthesis with a single command like \left and \right, something like the right term of  but using the code used for the left term. (The image is created using \left(1 + \left(f(x),g(x)\right)\right) and \Big(1 + \big(f(x),g(x)\big)\Big)) I could simply use \bib, \Big, ... but I don't want to keep track of the content all the time. I have no clue how to define a new set of \left and \right for this purpose.


How does grad school view a consistent B average in a course sequence?

I'm a math major, and in an undergraduate real analysis sequence I got a B- and B over the two semesters. A year later I took the first year graduate real analysis sequence and got a B+ and a B over the two semesters. I know there's a lot of outside factors to consider, but in general how do these grades affect my ability to get a Master's in Statistics and a PhD in Computer Science?  My overall GPA is an A-. How can I remedy this track record if it looks negative? Does it involve taking even higher level courses in Real Analysis  (i.e., comparable to 6000 level) and getting A's?


Finding $O(ab)$ when $O(a)$ and $O(b)$ are given in non abelian Group

Let $G$ be a non abelian group. If $ a$ and $b$ $\in$ $G$ and $O(a) = 3$ and $O(b) = 4$. Then what is the order of the element $ab?$   Now Since $O(a)= 3$ and $O(b)= 4$ , $O(G)$ must be of the form $12.n$ for some $n \in N$. therefore $O(ab)$ should divide $12.n.$  I dont know how to proceed from here...please give me a hint to solve this problem  $a) 6 \quad b) 12 \quad c)$ of $12k$ for some $k \in R \quad d)$ need not be finite


Installing ubuntu inorder to Install boot loader

I deleted my Partition for Ubuntu and my Windows OS cant load. How can I load Ubuntu into a USB so I can install the boot loader on my PC ?


How can I configure and print with an HP LaserJet 1000?

Could anyone help me to configure printer? I tried googling but haven't found anything.  EDIT: system->administration->printing there are no printers and cant add new one, add button is unclickable  at the beginning I didn't try to add printer and was installing those drivers, maybe I ruined something? I used this guide ubuntuforums.org/archive/index.php/t-112556.html by maulattu 3rd post..


Get null pointer exception when checking null input

I have a class like this.  public class Event {  public Event(String objectName, Integer moduleId, Integer actionId) {    if (StringUtils.nullOrEmpty(objectName)) {      throw new IllegalArgumentException("The objectName field is not supplied");   }   if (0 > moduleId || null == moduleId) {      throw new IllegalArgumentException("The moduleId field is invalid");   }   if (0 > actionId || null == actionId) {      throw new IllegalArgumentException("The actionId field is invalid");   }    objectName = objectName;   moduleId = moduleId;   actionId = actionId;  } }   When I test the null value for moduleId and actionId I got the null pointer exception. But it's fine for the objectName. Did I do something wrong?


How to stop Message memory full Internal phone storage is getting low?

I have been trying to get rid of this but nothing is working, and its super annoying please help! I've tried clearing cache but it didn't work.


Mathematical Induction proof for $(n!)^2 > n^n$

I have the math problem (induction proof - $n!^2 > n^n$) that I try to solve and I haven't yet managed to get it right so maybe somebody could help me.    My current plan solving the problem is the following :  1) for : $n = 1 \implies$ False; $n = 2 \implies$ false; $n = 3 \implies$ true  2) for $n = k \implies (k!)^2 > k^k$  3) $1^2 \cdot 2^2 \cdot 3^2 \cdot \ldots \cdot (k*k) > k^k $  4) $1^2 \cdot 2^2 \cdot 3^2 \cdot \ldots \cdot k > k^{k-1}$   move one k to right part of inequality  5) $k > \frac{k^{k-1}}{[(k-1)!]^2}$  I am aware that this proof is not complete! I would appreciate very much some help.  Thank you


Let A = $\begin{bmatrix}1 & 1 & 4\\0 & 3 & -4\\0&0&-1\end{bmatrix}$. Is the matrix A diagonalizable?  If so find a matrix P that diagonalizes A. Can you write A as a linear combination of rank 1 matrices formed from its eigenvectors? Determine the eigendecomposition $A = PΛP^{-1}$. A = $\begin{bmatrix}3 & 1 & 0\\1 & 2 &1\\0&1&3\end{bmatrix}$. Is the matrix A diagonalizable?  If so find a matrix P that orthogonally diagonalizes A. Can you write A as a linear combination of rank 1 matrices formed from its eigenvectors? (Note that A is real symmetric so that you do not have to compute the inverse of P).   My solution attempts:   det(λI - A) = $\begin{vmatrix}λ - 1 & -1 & -4\\0 & λ - 3 &4\\0&0&λ + 1\end{vmatrix}$ = (λ -1) (λ -3) (λ + 1) = 0   $λ_{1}$ = 1, $λ_{2}$ = 3, $λ_{3}$ = -1  ($λ_{1}I - A)x_{1}$ = 0  $\begin{bmatrix}0 & -1 & -4\\0 & -2 &4\\0&0&2\end{bmatrix}$ $\begin{bmatrix}x_{11}\\x_{12}\\x_{13}\end{bmatrix}$ = $\begin{bmatrix}0\\0 \\0\end{bmatrix}$   $\begin{bmatrix}x_{11}\\x_{12}\\x_{13}\end{bmatrix}$ = $x_{11} \begin{bmatrix}1\\0 \\0\end{bmatrix}$  It follows that $\begin{bmatrix}1\\0 \\0\end{bmatrix}$ is a basis for the eigenspace of A corresponding to $λ_{1}$ = 1.  In a similar way, I found other two basis vectors as $\begin{bmatrix}1/2\\1 \\0\end{bmatrix}$ and $\begin{bmatrix}-2/5\\1 \\1\end{bmatrix}$, and I got $P = \begin{bmatrix}1 & 1/2 & -2/5\\0 & 1 & 1\\0&0&1\end{bmatrix}$. Then my $P^{-1} = \begin{bmatrix}1 & -1/2 & 9/10\\0 & 1 & -1\\0&0&1\end{bmatrix}$. And I said A's left-multiplication by $P^{-1}$ and right-multiplication by $P (P^{-1}AP)$ gives the diagonal matrix Λ that is similar to A. I found Λ as $\begin{bmatrix}1 & 0 & 0\\0 & 3 & 0\\0&0&21/5\end{bmatrix}$. Then I said that if we multiply both sides of the equation $P^{-1}AP = Λ$ by $P$ from the left and by $P^{-1}$ from the right we get $PP^{-1}APP^{-1} = PΛP^{-1} = A$ and that this is the eigendecomposition of A. Here is my first question: Do you think I understood and did correctly what the asker wanted me to do by saying "Determine the eigendecomposition $A = PΛP^{-1}$."?   I started in the same manner and I got three eigenvectors as  $\begin{bmatrix}x_{11}\\x_{12}\\x_{13}\end{bmatrix}$ = $x_{12} \begin{bmatrix}0\\1 \\0\end{bmatrix}$,  $\begin{bmatrix}x_{21}\\x_{22}\\x_{23}\end{bmatrix}$ = $x_{21} \begin{bmatrix}1\\1 \\1\end{bmatrix}$ and  $\begin{bmatrix}x_{31}\\x_{32}\\x_{33}\end{bmatrix}$ = $x_{33} \begin{bmatrix}1\\-2 \\1\end{bmatrix}$.   I said A is not diagonalizable since the eigenvectors are not linearly independent.  Here is my second question: What the hell does the sentence "Can you write A as a linear combination of rank 1 matrices formed from its eigenvectors?" mean?


Nowadays i'm getting too much of spam emails from my contact form, below is it's html view,      <form id="contactForm" action="processform.php" method="post" class="positioned" style="display: inline;">

                 Name :                 <input type="text" name="senderName" id="senderName" placeholder="Type your name" required="required" maxlength="200">

                 Email :                 <input type="text" name="senderEmail" id="senderEmail" placeholder="Type your email" required="required" maxlength="200">

             Feedback :             <input type="textarea" name="senderfeedback" id="senderfeedback" placeholder="Type your Message here" required="required">

                                  <input type="submit" id="sendMessage" name="sendMessage" class="button" value="Submit">

         </form>   I think some auto bot is accessing my processform.php file. Is there any way to stop this ?


Why can one leave out the article in "Please contact administrator"?

As a native American English speaker, I wrote the following error message for our application: "There was an error. Please contact administrator."   A native German speaking colleague asked me why I didn't write, "Please contact the administrator."  Both of course sound correct to me, and I find thousands of instances of "Please contact administrator" when googling.  Why is it that as a native American English speaker, I find "Please contact administrator" correct while e.g. I don't find "There was error." correct?  Does anyone know of a linguistic rule which explains when one can leave out articles and when one can't?  It seems to have to do with headlines as someone suggested in the comments, but also instructions. Has there been any research on this to determine all the contexts in which articles can be omitted in this way?


155 GB in c drive used up. 50 GB used in minutes. Windows 7

My laptop has Windows 7 home premium. OS is installed on C drive. The C drive has some 155 GB but currently only 1.17 GB is free. I deleted contents of my download folder and moved the contents from my desktop and my documents. this freed some 50 GB. but within minutes it was full again. ran disk cleanup and gained some 2 GB. i checked size of all the folders ignored large sized windows and program files and program files (x86). Was baffled when users folder said 110 GB. went to my user folder and selected all files n checked properties it showed under 5 GB. So if i check my user folders properties it says 110 GB but if i check properties of its content its under 5 GB. BTW I am not using any anti virus program. Do you guys have any idea whats going on. Is my laptop possessed or something? :P Please help me out.


"He Isn't"/"She Isn't" V.S. "He's Not"/"She's Not"

Is there a difference in usage between "he isn't"/"she isn't" and "he's not"/"she's not"?  I think "he's not" and "she's not" are stronger because they put more emphasis on the word "not" than "he isn't" and "she isn't" do.


I want to show that $Z =\{(u^3, u^2v, uv^2, v^3) \mid  u,v \in \mathbb{C}\}$ is an algebraic set. So I need functions in $\mathbb{C}[x_1, x_2, x_3, x_4]$ that vanish for all $(u^3, u^2v, uv^2, v^3)$ where $u,v \in \mathbb{C}$.  I already found out that the function $f_{uv}(x_1, x_2, x_3, x_4) = -x_1 - 3x_2 - 3x_3 - x_4 + (u+v)^3$ vanishes at $(u^3, u^2v, uv^2, v^3)$. But how can I find one that vanishes for all complex numbers $u$, $v$?


World of Warcraft Stopped Downloading Ubuntu 13.10

I found out how to get WoW running on Ubuntu using Wine 1.5 and am able to play it (albeit somewhat slow, but that's mostly due to my hardware). It was downloading just fine and I could play without any errors.  But now that it has reached 85.5%. It refuses to download any more. It was stopped at 84.5 but I reloaded the Launcher multiple times and it moved another 1%.   I don't know why it stopped; the only thing I did was close the Launcher to resume it later (which hadn't caused problems until 84.5% downloaded). Everything loads and it seems like it is just lagging (the download speed wont show up and start downloading the game again).   Anyone know what I can do?   (Not using dual-boot with Windows, just straight Ubuntu)


Can't connect to Internet except via a VPN

A couple days ago all of a sudden my laptop stopped connecting to the Internet. For instance, if I open the Chrome browser (64-bit version 78.0.3904.97) and enter in the url textbox: apple.stackexchange.com, then after a long wait the following message appears:     This site can't be reached   apple.stackexchangecom's server IP address could not be found.   Try:   Checking the proxy, firewall, and DNS configuration   DNS_PROBE_FINISHED_BAD_CONFIG   This happens whether I connect with Ethernet or WiFi.  However, strangely, my VPN app (TorGuard v. 3.96.1) still manages to connect when turned on, and if I repeat the above scenario while the VPN app is on, Chrome downloads the apple.stackexchange.com front page.  Given the above error message, I should probably add that, as far as I know, I use no proxy or firewall, however if someone could explain to me how to check this definitively, I'll be grateful.  Computer: MacBook Pro (mid 2012) OS: macOS Catalina, v. 10.15    It has been suggested that this question is a duplicate of . I don't think it is, becaused the other question says: "I just tried at a friend's house to check, with no problems." In my case I don't think trying to connect elsewhere would have solved the problem, because the problem was with the DNS settings, which, to the best of my understanding, are configured manually, and don't simply change by moving the device to another location (but I'm not sure).


In the year 2000, someone probed the 3 dimensional quantum dots using a new condition which is important in semi conductor physics. But they basically solved the Schrodinger equation for ground state and discussed the consequences.  I have extended their work for general case , i.e, one can calculate "higher" state energy using those calculations. Also, I have pictured how the wave function looks like at higher states.  But I think that I have done just Math & some computations.     My query is : Is this result publishable owing to the fact that I am a Junior year student and I did this work without any adviser.


It seems that the voltage over ethernet ranges from 2 to 3 volts. How much current typically runs through the wires? I tried Googling with no success.  I ask this because I'm looking for components that are able to switch on and off an ethernet connection.


Clone bay damaged crew dead but backed up with DNA backup can you continue game?

I was in the format C version of the Rock cruiser and attacked the crew was killed and clone bay damaged had the Backup DNA augmentation. All the crew is suspended waiting to be cloned except there is no one to repair the clone bay! Aside from starting the game over completely is there a way to continue?


HP bs179tx Wifi not working on Ubuntu 14.04

I am using HP bs179tx.  I have installed Ubuntu 14.04 but I am not able to get my Wifi working.  It has Realtek driver installed in it   I do not see the option Enable Wifi in the network bar.


When does jumping down become falling, for damage purposes?

I understand that every 10 feet of distance fallen is 1d6 bludgeoning damage at the bottom... but how do you determine when to start calculating that if a player intentionally jumps down from a ledge? At what point does "dropping down" become "falling"?  I don't think it's based on the jump range measurements provided by the PHB, because the vertical distance is almost always less than 10ft, and the jump distances seem to be just an allowance to bypass terrain obstacles during your move by jumping over them.  Ten feet isn't that high and, while it can certainly hurt, 20 feet didn't kill me or break any bones. I expect more physically capable people would be able to jump down from higher, but I wouldn't dare do it myself — 20 feet was scary enough.  Clarification: In the absence of magic. How high is "a great height"? When dropping down, the only distance restriction is how high off the ground you are. Another example of this could be an aarakocra who chooses to drop from the sky to his feet, rather than flying down and landing. It's controlled because they chose to jump, so does that mean they're immune go damage regardless if height? Just because they wanted it? By that reasoning, saying "I meant to do that" could save your life. Is it just 10ft or more automatically becomes a fall unless magic is helping you? That seems totally arbitrary and random.


Upper left button of stack exchange communities vs. 'Questions' tab

I noticed, in the communities I'm subscribed to that if you click on the top left of the stackexchange community pull down menu, that it lists the questions of the community and when you click on 'Questions' in that community you get different questions.  Is there a difference in the two in the sorting of questions?


Monochromatic squares in a colored plane

Color every point in the real plane using the colors blue,yellow only. It can be shown that there exists a rectangle that has all vertices with the same color. Is it possible to show that there exists a square that has all vertices with the same color ? If it is not possible, please give me an example of a coloring of the real plane that does not have monochromatic squares.  To give the viewers an idea about other similar results (which they might find useful), for any coloring (2 colors) of the real plane:  1) There exists three collinear points having the same color, such that one of the points is the midpoint of the line segment that joins the other two.  2)For any two angles $\theta,\phi$ there exists a monochromatic triangle that has angles $\theta,\phi,180-(\theta+\phi)$  3)For any angle $\theta$, there exists a monochromatic parallelogram with angle $\theta$  Now its natural to ask if there are any monochromatic squares.  Thank you


Definition of a primary ideal in a commutative ring

The definition of a primary ideal $P$ is : $ x y\in P $implies either $x \in P $or $y^n \in P$ for some$ n > 0$.  My question is, why is it $x$ and not $x^n$ in the definition? Replacing $x$ by $x^n$ doesn't make a difference, does it?


How to iterate through an array of objects with checking the key of iteratees with the state?

Variable br must consist only of bool values. Which have been gotten by looping through the first array.  state ={     nonRelated: this.props.non_related.value,     1:true,     2:true,     3:false,     4:false,     5:true,    //  etc. }  let ar = [1,2,3,4,5,6,....20]; let br = ar.map(el => { return state.el })   Another example:   I need to filter the array, if the key in the iteratee (which is an object) in the state has the value "true".


I heard a voice mail message in the evening. What should I say: "You had left a message for me" or "you left a message for me"?


Custom ordering of duplicate targets is not necessarily honored on mobile apps

The order of duplicates is different between apps and web. :  iOS          App Version: 1.6.6.2 Device: Unknown (iPad7,3) OS Version: Version 12.2 (Build 16E227)   Android         App Version: 1.0.95 Device Manufacturer: LGE Device Model: LM-G710 OS Version: 8.0.0 (190492326deb8.FGN)   Web


Why Do we close our eyes while sneezing?

Google says germs  may fall on eyes from our sneeze but it happens all the time . Also it says it a part of contraction. What may happen if we sneezing wirh our eyes open ?


If I say "you will be paid up to today's date"

Does that mean you will be paid for the period ending the day before today or the period ending on today?  e.g. if today is the 31st August, do I pay until the end of August or until the 30th?


When I go to the rendered view, the object is very hard to see and I cant put any textures s on it.  and here is a rendered image of it  It's a .png file and the white surface should a plane, but there are no textures. This error corrupted every blender, including the already created ones. What should I do?


From my local machine I can copy files from a remote machine  scp remote:/some/file/path ~   But what if I'm already SSHed into the remote machine? Can I do something like this  ssh remote cd /some/file scp path local:~   where local somehow resolves to the machine I SSHed from. This would of course be possible if the local machine is running an SSH server and the remote is configured to connect to it, but that isn't always an option.  Is something like this possible?


Not being able to post more than once every 20 mins means I can't file all my bug reports easily

I'm trying to be a helpful citizen and file a whole bunch of bug reports for the Android app. But the 20-minute limit is getting in my way; really unhelpful for everyone involved. I've got lots of tabs open ready to go...


Another question asks,  Rather than the background, I am interested in blurring the foreground. What techniques or advice are different for achieving sharp subjects with strongly blurred foregrounds? Note that I'm not asking how to use an editing program to achieve this effect after in post production or after the image is captured. I am using a Nikon D7200 with an AF-S 18-140 mm VR Lens


Book series with humans vs. Demons and dragon bone ships

I'm looking for a series of books about a war between humans and demons who traveled to floating chunks of shattered worlds via boats made of dragon skin and bones?  I remember a couple of wizards, a guy that uses a cloak as a weapon, and a scorpion demonlord fighting other demonlords for dominance.


Looking for a short story where humans kidnapped by aliens live in a simulation

Looking for a short story where a group of humans are stuck in a game like simulation, they break out of the simulation only to find that they were in hibernation and playing the game to pass time. However the plot twist is that they're actually astronauts who were kidnapped by aliens, and the reason why their simulation is so game like is because the aliens made it based on the video games the astronauts played. Thanks in advance


Tell me before I start editing that I can't suggest edits

On sites where I don't have the edit privilege, the iOS app still lets me make all the improvements I want to a post, but won't let me submit them:    Could the app warn me with this message before I spend a bunch of time editing the post?


What's the difference between CPU and MPU?

Can somebody explain what's the difference between these two terms? This answer  contradicts with what I found on the internet:  CPU is essentially a microprocessor, not all microprocessors are CPUs.  vs  A microprocessor is essentially a processor that happens to be on a chip (or a small number of chips), as opposed to one made from a large number of individual components.  in the answer. As far as I understood, MPU contains in it CPU + additional stuff, specific to its purpose. GPU is a MPU, even a sound card is a MPU. CPU itself is used when we refer to the main processor of the computer. Am I right? Also, I've found this image:


Is there a simple way to remove special characters (such as é, É, à, ç etc.) from a given string, via a command \removeSpecialCharacters{...}? More precisely I would like to remove all characters but a...zA...Z0...9 and, if possible, replace the accented characters by the non-accented characters.


Normal force in a compound pendulum (physical pundulum) system?

Consider a compound pendulum pivoted about a fixed horizontal axis, illustrated by the force diagram on the right:  # Okay, I can't figure out where the normal force on the pendlum should point (this force isn't indicated in the diagram). On the one hand, I think it should point in the same direction as the tension force on the left-side diagram, in order to produce the rotation. But on the other hand, shouldn't the normal force point towards the pendulum rather than away from it? In any case, I know that normal face is perpendicuar to the contact surface, but how does "contact surface" fit into the context of this scenario? Please help me understand the concepts involved.


Distribution of the top $m$ of $n$ samples of a Gaussian distribution?

I was wondering if there was an analytic description of the distribution of the largest $m$ of $n$ samples of a Gaussian distribution, where $n \geq m$.  (As an example, I generated 100 samples from $\mathcal{N}(\mu = 0, \sigma = 1)$. The average of the top 100 samples came to $0.0404$, the average of the top 50 samples came to $0.832$, the average of the top 10 samples came to $1.842$, and the top 1 sample was 2.88.)  Intuitively, as $n$ increases and $m$ stays constant, or $m$ decreases and $n$ stays constant, the expected value increases. It's like taking the top $m$ applicants.  Is there a name or analytic description of such a distribution?  (I haven't been able to figure out how to do this, and I spent a lot of time searching. This seems like a simple / common problem and I'm surprised I haven't found anything on it.)  EDIT: After the comments below, I as able to find a good answer here:


Im still searching and trying to manage with this float figures but with no success. I really need that my figures stay right at the place that they are called, not on the next page! My document is something like this:  Executamos o algoritmo, geramos nossos dados e plotamos o nosso gráfico. Vide Figura ~\ref{fig:exampleFig5}.  \begin{figure}[htbp] \centering \includegraphics[width=.7\textwidth]{alg3.png} \caption{} \label{fig:exampleFig5} \end{figure}  O resultado do gráfico não representa uma reta, logo, teremos que analisar o comportamento deste algoritmo. Aplicamos o log dos valores do eixo y e replotamos o gráfico. Vide Figura ~\ref{fig:exampleFig6}.  \begin{figure}[htbp] \centering \includegraphics[width=.7\textwidth]{alg3y.png} \caption{} \label{fig:exampleFig6} \end{figure}  Com o grafico gerado, continuamos sem saber a característica deste algoritmo. Vamos tirar o log do eixo x e novamente replotar o gráfico. Vide Figura ~\ref{fig:exampleFig7}.  \begin{figure}[htbp] \centering \includegraphics[width=.7\textwidth]{alg3xy.png} \caption{} \label{fig:exampleFig7} \end{figure}  The text is in portuguese, but this doesnt matter. The question is: why the figures are going to the next page if i call them right after the text with this: [htbp] ?  Sorry, i dont know how to use the code format in this editor


Possible Duplicate:        $b$, $x$, $y$, $z$, $\ldots$ are integers greater than 1. How can we prove that  $$ \gcd (b ^ x - 1, b ^ y - 1, b ^ z - 1 ,\dots)= b ^ {\gcd (x, y, z, \dots)} - 1\ ? $$


Does everyone see the same "Hot Network Questions"?

Hot Network Questions are wonderful to discover things one never expected to read about. I was always wondering whether the list seen on the side bar, or the one at  are the same for every Stack Exchange visitor, or whether they are filtered based on some criteria? (logged in or not, most active networks for the user, previous visits to a SE site from HNQ, ...)


Can a single ground wire ground 2 outlets? I don't want to run another wire through the wall, if I can run a wire to that other ground wire (and have 2 outlets being grounded by one wire).  In other words,     I also have concerns about equipment protection.  Will adding a ground wire be worse for my electronic equipment in any way?   If I am having problems with equipment taking damage, will this help?


I need soup help. I am unable to make a homemade soup with pasta. If I make chicken noodle I have to add cooked noodles just before we eat it. Otherwise all my soups turn out like a goulash. The pasta absorbs all the water .   Today I cooked a very tasty, successful, tomato based, beef macaroni soup with zuchini.... o.m.g. yum! It did look like soup at one point. And I'm so glad I snuck a bowl while it was soup cuz I turned the burner off to let it cool, came back to goulash. No more soup. Ugh!  I've also failed at freezing left over homemade chicken noodle soup. The pasta turns to mush.  It sure tastes good. But not what I wanted Help!? Thanks guys!


Batch fit images into ratio with blurred background

I need to resize a lot of images into a 4:3 ratio with the desired effect.  Is there a way to do this using photoshop actions? (the background can be scaled or two copies moved to the sides, either way works)     image credits:


How can one prove that the random sample is normally distributed if the sample mean and sample variance are independent?


Two cases:   When should numerous numerical predictors be grouped? is it just based off some theoretical knowledge on the predictors?  When should levels(>2) in a factor be grouped together?


Is exponential map locally a diffeomorphism w.r.t. base point?

Let $M$ be a riemannian manifold and $\exp_p: T_pM \rightarrow M$ the exponential map at $p \in M$.  At each point $p\in M$, $\exp_p$ can be restricted to a neighborhood $V$ of $0\in T_pM$ so that $\exp_p|_V$ is a diffeomorphism. Let $U\subset M$ denote image of $V$ under this map.  Choosing an orthonormal basis $\{E_i\}$ for $T_p M$ and using the isomorphism $E: \mathbb R^n \rightarrow T_pM$, where $E(x^1, \dots, x^n)= x^iE_i$, gives normal coordinates $(U, \phi)$, where  $$ \phi := E^{-1} \circ \exp^{-1}_p: U \rightarrow \mathbb R^n $$  My question is: can we fix some $z\in \mathbb R^n$ (small enough) and take some small neighborhood $\widetilde{U}$ of $p$ so that the function $\widetilde \phi$, defined as $$ \widetilde{\phi}_z (p) := \exp_p ( E(z)) $$ is a diffeomorphism when restricted to  $\widetilde{U}$?  (In the definition of $\widetilde \phi$, the isomorphism $E$ will also vary with $p$.)


Weird behavior of constructor instance for prototype property

Refer to the given example:   Code:  var Person = function (name) {     this.name = name; } var john = new Person("John"); console.log(Person.prototype);//Object{}    console.log(john.prototype);  //undefined   Person is a function so its prototype would be derived from object so its understandable that it gives an Object in return (which further has Constructor & proto) as its properties.   Coming to second console statement. As, john is an instance of Person, therefore it must have the same prototype as Person has. Means, I should have got an object in return. How am I getting undefined? Can someone explain?


I'd like to delete everything from this pc's HDD. It has Ubuntu on it, so I can't reformat it. I got a Live CD with Ubuntu 12.04 on it from a library.   I went to BIOS and set DVD-ROM as the first boot device, saved and rebooted. It still boots into Ubuntu 16.04 that is on my HDD, so I can't delete the partion.   The CD shows up in the Home Folder with the name "Ubuntu 12.04 LTS i386" it has all the files in it, so the CDROM is fine. What should I do? I do not have multiple partitions. My problem is the PC won't boot using the CDROM, so I can't delete the partion with ubuntu 16.04 on it. I am planning on installing Steam OS so I'd like the drive to be clean.


Im working a small "search engine", and im trying to improve it to prevent mysql injection, but im new to php and I don't know how :/ any ideas.  I already look some tutorial on google but not with a luck :/  require("../login/connect.php"); $search = $_GET['query'];  $search = "%".$search."%";  $query = "SELECT * FROM mobiles WHERE (`name` LIKE :search) or (`type` LIKE :search)";   $query_params = array(':search' => "%".$search."%");  try {   $stmt = $db->prepare($query);   $result = $stmt->execute($query_params); } catch(PDOException $ex) {   die("Failed to run query: " . $ex->getMessage()); }  $rows = $stmt->fetchAll(); $count = $stmt->rowCount();  $min_length = 3; if(strlen($query) >= $min_length) {   echo "
";    echo "
           Mobile Name	           Mobile Type
";   if ($count > 0)    {     foreach($rows as $row):     {        echo "
               ". $row['name'] ."	 ".$row['type']."
" ;     }     endforeach;    }  else   {      echo "
Sorry..No results for $search
";      echo "
";     } }


Would you capitalize the job title in the following sentence?      I am writing this letter in regard to Joe Brown who is applying for the director of teaching and learning position in the XYZ School District.


How to convince immigration officers on accommodation while on a travel trip availing couchsurfing?

I'm from India and I was wondering how to get around the situation, when I am going for a travel trip to a country (any country for that matter) abroad, but haven't booked a hotel as I am planning to do a couchsurfing. The period of stay could vary between 5 days to 1 month, out of which, suppose I received confirmation of stay for an initial couple of days from a couch surfer.   1)In such a scenario, how do I clear the interview by the immigration officer when asked to provide my accommodation arrangements? Will simply telling the truth about relying on couchsurfing be wise to get clearnce by the officer? 2)Is it even an option to book a hotel through websites in advance and cancel the booking after I get clearance from the immigration officer? In that case, will I be liable to pay cancellation charges- or-the whole booking amount gets deducted from my credit card account?  The questions might sound silly to many, but I am seriously looking for your guidance on this as I will be planning visit to different countries depending mostly on couchsurfing for accommodation. Thanks in advance.  Additional Notes: Currently I hold a B1 valid for 9 more years. I have visited UK and USA once and twice respectively on business purpose- if this info helps. And I'll be planning for travel trip to USA/UK/Europe/south east Asia


bit of a beginner here. I'm using Blender to design an electronic Cello. I want to flatten out the faces highlighted here so I can saw from a flat sheet of thin plywood which will then be wrapped to the 3D shape shown. I thought Mesh>Cleanup>MakePlanarFaces might work but sadly not. Any ideas?


Salesforce and JIRA integration using OAuth

For last few days I am trying to figure out the ways of implementing this type of integration using OAuth.  I've got a community from which I wanna make requests to JIRA to create/get/delete/edit issues. I have no problem with making these requests, using basic authentication, but I am tasked to do it, using OAuth.  So, I've got several questions:   What needs to be configured (on org and on JIRA side)? What data do we need to store in org for that?   Thanks, in advance.


I have Tex Live installed. Everything look fine, pdfpages show any particular page I want, but when i want to print all pages via command:   \includepdf[pages={1-5}]{vyzkum/Form.pdf}   ! Missing = inserted for \ifnum.   <to be read again>                 -   l.6014 \includepdf[pages={1-5}]{vyzkum/Form.pdf}   or      \includepdf[pages=-]{vyzkum/Form.pdf}    ! Package pdfpages Error: Cannot find file `-'.     See the pdfpages package documentation for explanation.    Type  H <return>  for immediate help.     ...                                                   l.6014 \includepdf[pages=-]{vyzkum/Form.pdf}   The default (no range spacified):    \includepdf{vyzkum/Form.pdf}   It shows only the first page  Any comment/help is deeply appreciated!


How to add class on a textbox if its empty? I am using getmdl.io framework. What I want to do is when the textbox is empty I want to add a class which is (is-focused, is-invalid and is-dirty)
      <input class="mdl-textfield__input" type="text" id="fullname" name="fullname" autocomplete="off">      Full name
   and this is my javascript code when the submit button is click.  function validate () {     var f = _('fullname').value;     if (f == "") {         _('fn').className += " is-invalid";     } }


Can participial adjectives be placed without a noun after them?

Adjectives are placed before nouns. But sometimes I've seen (though I'm not sure if they are correct), things like:     The item placed there   I know that it may be a short way of saying "The item which is placed there".    Is the past participle "placed" considered as an adjective in that sentence? Can any past participle used in this way by ommiting the relative pronoun+subject of the relative clause? Is there any exception for the rule that adjectives must be placed before noun?


I can't understand the truth table of implication  I could understand that  'if p then q' : true     then   'if p then not q': false  But why  'if not p then q' and 'if not p then not q' are true?  I thought that they can be true and false depending on the situation.  But why are they both true?


I have string s="if(a<b) c else d", Please help me solve it?

var a=50; var b=20; var c=0,01*a; var d=0,1*b; var s="if(c<d,a,b)"; var result=?;   So how i can get value of string s by using C#?


Which ones we should use:   the global population global population


how can I change svn folder to normal folder

In git I can remove .git folder and after that, the folder is considered as a normal folder, I wonder how can I do the same for svn folder?


Proving $\frac{\sin n\theta}{\sin\theta}= 2^{n-1}\prod_{k=1}^{n-1}\left(\cos\theta-\cos\frac{\pi k}n\right)$

I have to prove $$\frac{\sin(n\theta)}{\sin(\theta)}= 2^{n-1}\prod_{k=1}^{n-1}\left(\cos(\theta)-\cos\left(\frac{\pi k}{n}\right)\right)$$  $$\sin(\theta) = \frac{e^{i\theta}-e^{-i\theta}}{2i} ,\qquad\sin(n\theta) = \frac{e^{in\theta}-e^{-in\theta}}{2i}.$$ So \begin{align*} \frac{e^{in\theta}-e^{-in\theta}}{e^{i\theta}-e^{-i\theta}} & =\frac{e^{2in\theta}-1}{e^{2i\theta}-1}\cdot e^{-i\theta(n-1)} \\ & =\frac{(e^{2in\theta}-1)(e^{-2i\theta}-1)}{(e^{2i\theta}-1)(e^{-2i\theta}-1)}\cdot e^{-i\theta(n-1)} \\ & =\frac{e^{i\theta(n-1)}+e^{-\theta(n-1)}-e^{i\theta(n+1)}-e^{-i\theta(n+1)}}{2-e^{2i\theta}-e^{-2i\theta}} \\ & =\frac{\cos((n-1)\theta)-\cos((n+1)\theta)}{1-\cos(\theta)}. \end{align*} Can I get my desired result from here or I made a mistake?


Accessing values of dict inside list with indexes

I had a requirement in one of my codes to access values from a list of dictionaries that I initialized with default values. My object looked like this:  >>> lengths = [{"max_len":0,"eq_len":True}] * 7 >>> print(lengths)  [{'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}, {'max_len': 0, 'eq_len': True}]   Surprisingly, when I'm trying to update any one of the values in this lengths object directly, all the other objects are also getting updated. For ex:  >>> col_lengths[0]["max_len"] = 10 >>> print(col_lengths)  [{'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}, {'max_len': 10, 'eq_len': True}]  >>> col_lengths[4]["eq_len"] =  False      >>> print(col_lengths)  [{'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}, {'max_len': 10, 'eq_len': False}]   Looks like this behavior is unexpected. Or am I doing something wrong? Can someone please help me with this?


discerning between the usage of raise and rise?

I am wondering if there is any difference between the bold parts? these are extracted from Longman:  rise:  increase:  to increase in number, amount, or value [= go up; ≠ fall] raise: increase   to increase an amount, number, or level [≠ lower]:


We have like 20 Office 2010 Product Key Boxes but we have no clue which one are used and which one are free.  Is there any way to check which one are free?


Nautilus file manger is not showing up in taskbar

When I open up natuilus ( the default ubuntu file manger), the icon does not appear in my task manager so when I want to go back to that same session, I simply cannot. I wonder if this is a known problem. using 16.04.


Can somebody please fix my code? I keep getting an error saying:     'pygame.Surface' object is not subscriptable   on line 40 where it says   SURF.blit(Dirt[tilemap[row][column]], (column*tilesize, row*tilesize))  I'm using pygame and I'm very new to python. Thank you for any help, its greatly appreciated.      import pygame, sys     import Sprites     import random      pygame.init()      from pygame.locals import *      #DISPLAY = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)      pygame.init()      infoObject = pygame.display.Info()      print(infoObject.current_w, infoObject.current_h)      tilesize = 40      TILESX = infoObject.current_w // 40     TILESY = infoObject.current_h // 40      print(TILESX, TILESY)      WHITE = (255, 255, 255)     BLACK = (0, 0, 0)      Dirt = pygame.image.load('Sprites/Dirt.png')     textures = {        Dirt    }    tilemap = [[Dirt for w in range(TILESX)] for h in range(TILESY)]     SURF = pygame.display.set_mode((TILESX * tilesize, TILESY * tilesize))     while True:  for row in range(TILESY):     for column in range(TILESX):         SURF.blit(Dirt[tilemap[row][column]], (column * tilesize, row * tilesize))  pygame.display.update() for event in pygame.event.get():     if event.type == pygame.QUIT:         pygame.quit()         sys.exit()   input()


How to fix, or document for users: Escaped backtick rendering, in question/answer or comment

Noting this duplication of topic, I hope this question can also address, what else might be easily done? This is a bug, or should be added to editing notes.  Congratulations you discovered meta._.stackexchange.com and meta.stackexchange.com  is not a great help. This is indeed a duplicate in trying to understand what's happening. About 40 (2/3rds of the 60 or so)  relate to this.  In the question & answer editor, the input: `\``  produces the output: ``` Whereas in the comments, the same string correctly renders a code block containing a back-tick.


Proving $\sum_{k = 0}^n k\binom nk^2 = n \binom{2n-1}{n-1}$ with combinatorial proof

Prove that $$\sum_{k = 0}^n k\binom nk^2 = n \binom{2n-1}{n-1}$$  I have to prove it in a combinatorically. No induction or algebra.


I had raised a  to merge pre-build-event, and pre-buildevent; and postbuild-event and post-build-event. That was about 11 months ago, and I still see these two tags even now.  How are tag merge requests handled? Is there a better way for tag merge requests other than posting on Meta?


How can I convert an array of objects with dynamic keys into a single object?

I am trying to convert this array of objects into a single object:  const arr = [   {day: "15/06/34", id: 40, time: "2000", type: "time"},   {duration: "240", id: "ZF3P49", name: "Race", title: "First ever"},   {message: "Try to beat me"},   {car: "Ferrari", userId: "D0Ek5Y"}, ]   I don't consider this to be a duplicate of  as that one only covers keys that are not dynamic.


Is there a common way to get the current time in or with milliseconds?  There is os.time(), but it only provides full seconds.


Every compact metric space is complete, proof verification

I want to give a proof, that every compact metric space is complete.  Proof:  Let $(X,d)$ be a compact metric space. Let $(x_n)_{n\in\mathbb{N}}$ be a Cauchy sequence. The theorem of Bolzano-Weierstraß yields, that $(x_n)$ has a convergent subsequence $(x_{n_k})_{n_k\in\mathbb{N}}$.   Note $x:=\lim_{n_k\to\infty} x_{n_k}$.  I want to show, that $d(x_n, x)\to 0$.  Let $\epsilon >0$ be arbitrary.  Since $d(x_{n_k}, x)\to 0$ exists for $\epsilon/2 >0$ a $N'\in\mathbb{N}$ such that $d(x_{n_k}, x)<\epsilon/2$ for every $n_k\geq N'$.  Likewise since $(x_n)$ is a Cauchy sequence, we find for $\epsilon/2>0$ a $N''\in\mathbb{N}$ such that for every $n,m\geq N''$ holds, that $d(x_n,x_m)<\epsilon/2$.  Take $N:=\max\{N', N''\}$ and we conclude the proof:  $d(x_n, x)\leq d(x_n, x_{n_k})+d(x_{n_k},x)<\epsilon/2+\epsilon/2=\epsilon$.  Therefor $\lim_{n\to\infty} x_n\to x$ converges and $(X,d)$ is complete.  I would appreciate your thoughts on my proof. Thanks in advance.


I know that as the velocity increases, the mass of the object also increases so it becomes tougher and tougher to move the object which ultimately leads to a requirement of infinite energy to accelerate an object to the speed of light. But I have a doubt.  As far as I know only the observable mass (Relativistic mass) increases but not the Proper Mass or Intrinsic Mass, right? The actual mass of the object will remain the same. So if the actual mass ($m_0)$ remains the same and only the observable mass increases, why is more and more energy required? I know that even if the object exceeds the speed of light, we will not be able to say that it is moving faster than the speed of light but is it possible to make it move faster than light?  If rest mass does not change with $v$ then why is infinite energy required to accelerate an object to the speed of light?  I quote Igor Ivanov (a stackexchange user from this question ) to give an insight into my question.     The mass (the true mass which physicists actually deal with when they calculate something concerning relativistic particles) does not change with velocity. The mass (the true mass!) is an intrinsic property of a body, and it does not depends on the observer's frame of reference. I strongly suggest to  popular article by Lev Okun, where he calls the concept of relativistic mass a "pedagogical virus".   EDIT  After reading the answers I have a doubt.  SO can I say that only the overall energy of the system increases while the mass remains constant? But then if mass remains constant, then why is more and more energy gradually required? I mean there should be a reason for that requirement of infinite energy.


I recently had my computer brought to the the Genius Bar, and they installed a copy of OS X Snow Leopard onto my computer. However, I was previously running Lion. So I went over to the Mac App Store to try and reinstall Lion, and it keeps telling me that the item I've requested is not available in the U.S. Store. Is there any way I can resolve the issue? I've tried switching stores and had no luck.


How to prove some statistical model to be dominated?

I have a model following the PDF $$f_\theta(x) = \theta^2 x \exp(-\theta x)\delta_{[0, +\infty)}(x)$$ where $\theta > 0$ is the parameter and $\delta_\mathcal{S}$ denotes the indicator function of the set $\mathcal{S}$.  I am ask to prove that this model is regular, for which I have to prove that it is dominated. How should I do that?  Below is the definition of "dominated" that I found the the book Theory of Point Estimation by E.L. Lehmann and George Casella:     Statistical problems are concerned not with single probability   distributions but with families of such distributions $$\mathcal{P} = \{P_\theta, \theta\in\Omega\}$$ defined over a common measurable space   $(\mathcal{X}, \mathcal{A})$. When all the distributions of   $\mathcal{P}$ are absolutely continuous with respect to a common   measure $\mu$, as will usually be the case, the family $\mathcal{P}$   is said to be dominated (by $\mu$).      Most of the examples with which we shall deal belong to one or the   other of the following two cases.      (i) The discrete case. Here, $\mathcal{X}$ is a countable set,   $\mathcal{A}$ is the class of subsets of $\mathcal{X}$, and the   distributions of $\mathcal{P}$ are dominated by counting measure.      (ii) The absolutely continuous case. Here, $\mathcal{X}$ is a Borel   subset of a Euclidean space, $\mathcal{A}$ is the class of Borel   subsets of $\mathcal{X}$, and the distributions of $\mathcal{P}$ are   dominated by Lebesgue measure over $(\mathcal{X}, \mathcal{A})$.   Thank you in advance for any help!


What is the (triplet) eigenstate for two electrons?

Let's assume I have a harmonic oscillator which is one dimensional. What is my plan is to work the the two electron's spin states and my requirement is that they have to be in the triplet sates.  Lets also consider that wave function which is $\Psi (r_1,r_2) \ \chi(1,2)$  If the radial wave function is antisymmetric, the spin part has to be symmetric to have two electron triplet states under the given conditions.   There are three possible values of $m_z$ (1,0,-1) in the triplet states which are symmetric spin states. But if I asked to write down, how would be the spin state of the total function?   Is it going to be something like this:   $$\chi(1,2) = a |{\uparrow \uparrow} \rangle + b |{\downarrow \downarrow} \rangle+ c \frac{1}{\sqrt{2}}\Big(|{\uparrow \downarrow} \rangle + |{\uparrow \downarrow}\rangle\Big)$$  The reason I did this because I thought all the spin states could be possible.


Is transit visa required for London, UK when travelling from USA to India while on expired US visa?

I am an indian national, currently staying in USA. My current H1B Visa has expired and I am planning to travel back to india via London, UK.  Will I require an airside transit Visa for London?


Let $OABC$ be a regular tetrahedron. Using   $OA=a,~OB=b,~OC=c$, prove that  $QT$  bisects  $PU$ where $P,U,Q,T$ are mid points on the edges of a regular tetrahedron. P is the midpoint of OA. T is the midpoint of AC. U is the midpoint of BC. Q is the midpoint of OB. Midpoints; P and Q are midpoints on the edges of the base of the tetrahedron.  Going about this I thought that I would prove that $PUQT$ forms a a parallelogram and then prove that $QT$ bisects $PU$, however I may be wrong.


I am really looking for the answer. I will be happy to hear your answers. Thanks Question:  She brought her three friends, none of .... I have ever met before.  who which whom whose


Can't remote into a computer because "the remote computer requires Network Authentication"

I'm trying to remote into one Windows 7 computer from another Windows 7 computer, and am getting this error:     The remote computer requires Network Level Authentication, which your computer does not support     I believe my computer does support Network Level Authentication, because:   I'm on Windows 7 I have remoted into the target computer from this computer before, with Network Level Authentication required on the target computer The "About" dialog of mstsc.exe says that it is supported:     Has anyone seen this issue before, or know how I can fix it?


Painting the faces of a cube with distinct colours

I don't think this is solved by Burnside's Lemma since there is a condition that each side is painted a different colour. The question is as follows.      If I had a cube and six colours, and painted each side a different colour, how many (different) ways could I paint the cube? What about if I had $n$ colours instead of 6?   The answer given in an old thread on a different site is $6!$ for the first question, and $n(n-1)(n-2)(n-3)(n-4)(n-5)$ for the second question. However, this doesn't actually hold up because a few of the paintings are isomorphic. The original thread assumes we can somehow tell the difference between two paintings which actually look identical if you rotate the cube, which I don't think is what the question intended.  The answer I got for the first question is $4! + 4 = 28$. But this was just through a case-bash, and I'm not sure whether it's correct or whether it generalizes.


Get nested list of dynamic objects to be displayed as tree

I have these two classes  public class Category {     public int Id { get; set; }     public string Name { get; set; }     public int? ParentId { get; set; } }  public class CategoryVm {     public int Id { get; set; }     public string Name { get; set; }     public List<CategoryVm> SubCategories { get; set; } }   and I have a list of the first class and I want to convert it to the second form to be displayed inside a tree view.    Example input    Example output


Counting degrees of freedom of gauge bosons

Gauge bosons are represented by $A_{\mu}$, where $\mu = 0,1,2,3$. So in general there are 4 degrees of freedom. But in reality, a photon (gauge boson) has two degrees of freedom (two polarization states).   So, when someone asks about on-shell and off-shell degrees of freedom, I thought they are 2 and 4. But I read that the off-shell d.of. are 3.   And my question is how to see this?


Can I update to iOS 8.3 using IPSW files?

I recently received an iPhone as a gift. It had not been used in a while, and as such, had been left un-updated on iOS 6.0.1. I am a jailbreak enthusiast, and since there may not be an iOS 8.4.1 - iOS 9 jailbreak, would it be possible to update to iOS 8.3 with its IPSW file (despite it not currently being signed)?


Build Interactive Web map for offline/localhost visualisation

I am part of a small research project where we are leading field experiments in a small watershed, on some remote location far away from our research institute.   I have a series of vector data, shapefiles actually, consisting of various points, lines, polygons, each one representing some specific entity on the field: either rain gage stations, drillings, boreholes, contours, roads, parcels, etc... Also, for those entities, I have some photos taken with a camera to illustrate the actual state of the entity.  I would like to build a series of maps. I want them to be interactive, so that people can choose thematic layer entities of interest and display them, measure distances, etc. Also, it would be good to run them locally on the browser, without the need to install some third party software.  I don't have a clear idea on the way to go. Can anyone help pointing me in the right direction ?


I have tried almost everything and scratched my brains over it but still, I am not able to figure it out. Please help me to achieve this lettering.


Is it possible to mirror the apt repositories?

I am a student at Case Western Reserve University, and the bandwidth from the Ubuntu servers to my location is often horrendously bad (on the order of a few hundred bytes per second). Myself and a few friends would like to be able to download the packages once, and have them cached for the rest of our Ubuntu installations on campus. To do that, we would either need to setup our own APT repositories, or setup some form of caching (squid?) server at which we could point our systems.  Is setting up such a mirror a difficult process? How would one accomplish it?


If someone takes a decision, can someone tell me where they intend to take it? Call me old fashioned or conservative if you like but I was always taught to make a decision and once it's been done it's made.  I do not intend to take it anywhere. Verbally speaking there is a great difference between take and make..........just as there is a difference between stick and put.  Does anyone have any glue?


OnClick doesn't work at js created button

In my program I create buttons with javascript and they should start an function but they don't. If I press the button on my program the browser says "can't find variable" how can I fix it that the button starts the function.  JS-Code  $(document).ready(function(){ function myfunction() { alert("pls"); } var Id = sessionStorage.getItem('Id'); var status = 0; var nummer = 0; $.ajax({ type: "POST", url: "http://localhost/jQuery&PHPnew/Markt.N.php", data:{status:status}, success: function(data){     var anzahl = 1;     status = 1;     while (anzahl>nummer) {       nummer++;     $.ajax({         type: "POST",         url: "http://localhost/jQuery&PHPnew/Markt.N.php",         data:{nummer:nummer, status:status},         success: function(data){           var Daten = JSON.parse(data);           var Ausgabebereich = document.getElementById('main');           var f = document.createElement("form");            var bInhalt = document.createElement('button');           var Inhalt = document.createTextNode("Senden");           bInhalt.appendChild(Inhalt);           bInhalt.setAttribute("type", "button");           bInhalt.setAttribute("onclick", "myfunction()");           f.appendChild(bInhalt);            Ausgabebereich.appendChild(f);          }         })       }      }     })   })


This may be a duplicate, but I did a thorough search and couldn't find it.   It would be useful to have the original question visible when composing an answer. I often want to reference the question to use the askers variable names, and check my wording.


I have an issue with xrdp being unable to display gnome fallback session in 13.10 - connection works fine but everything I get is Xserver grey screen and X cursor.  My hardware config is ATI HDMI with dual display on ATI drivers.  What I have done until now:   Installed xrdp (no tightvnc), gnome-session-fallback from terminal. Created .xsession file in my home dir: gnome-session --session=gnome-fallback Restarted xrdp several times, restarted Ubuntu   At the moment file is owned by the user I am trying to connect as and has executable privilegs.  What I get after connection from Windows 8.1 laptop is Xserver grey desktop and no chance to play.  .xsession-errors says:  Xsession: Xsession started for at ....  X error of failed req: BadValue (Integer param out of range)  Major opcode for failed req: 109 (X_changeHosts)  Value in failed req: 0x5  ...  gnome-session-is-accelerated: No composite extension  gnome-session-check-accelerated: Helper exited with code 256  gnome-session-is-accelerated: No composite extension  gnome-session-check-accelerated: Helper exited with code 256   I have already reinstalled system like 20 time to solve some issues but being unable to RDP is a no go for me.  When I installed xfce4 it was working fine. What's wrong with my gnome-fallback?


Very slow computer but low CPU or Memory usage

My computer is very slow. All the programs and Windows itself is slow. But strangely, all the games run without lag. They are not affected somehow.  I just reinstalled my computer for the 6th time this year, and it is not getting any better. It is always lagging. All the parts are new, bought around November 2013.  These are my specs:   CPU: Intel Core i5-3350P at 3.10 GHz GPU: AMD Radeon HD7770 HDD: Toshiba 2TB, 7200 RPM RAM: 4GB Kingston, DDR3 at 1333 MHz Motherboard: Gigabyte Z77-HD3 Audio: M-Audio Firewire 410 (external audio card)   I am using this computer for recording music.    OTL reports  I read it can be usefull, so I ran the program and here they are:   OTL.txt -  Extras.txt -      One more thing! My computer can't sleep! When I hit the sleep button in Windows, it either restarts or sleeps, but then I cannot wake up the monitor.  If someone could tell me why my computer is so slow, I would be very grateful!


High RAM usage by svchost.exe and chrome.exe

I don't know why while my laptop is sitting idle , it uses a lot of RAM , searching in task manager I found the process svchost.exe. , how can I remove it or is it normal. I have 3GB RAM. and my gadget shows RAM usage over 70%.I have listed all high usage processes shown in task manager.  edit i have also found chrome stealing my memory , while only one tab of chrome is open.


How to scan an entire network using Nmap?

Is there a way to scan an entire network using ?   What I want to do is scan my network for all the devices that are currently connected to it.


The story peripherally involves a corporation named Eight Colors, but also includes a plot about people living underground, viewing the surface through prisms and periscopes. Near the end the protagonist takes a group of people to the underground community, where they are psychoanalyzed, and their emotions are encoded on shifting color badges they wear on their shirts or sleeves, i.e., literally wearing their feelings on their sleeves.


Kali Linux: apt update returns "Hash Sum mismatch" error

I'm experiencing exactly the same issue as described in this question: . Before you mark this as a duplicate however, I have tried the solutions posted there, as well as on numerous other sites, including:  sudo apt-get clean sudo rm -rf /var/lib/apt/lists/* sudo apt-get update   Editing /etc/apt/sources.list with alternate official mirrors, such as  deb http://mirrors.ocf.berkeley.edu/kali kali-rolling main non-free contrib or deb https://http.kali.org/kali kali-rolling main non-free contrib  Everything worked after I first imported the VM. I ran sudo apt update and it found some ~650 packages to upgrade. I ran sudo apt upgrade and it encountered an error partway through. That error was solved using sudo apt --fix-broken install, but that is when this hash sum error began. Unfortunately due to hours of troubleshooting I no longer have the details of the earlier error, but I believe it was an error extracting a package due to corrupt data.  I've tried multiple official mirrors, but I get the same error. Additionally, when I downloaded the Packages.gz file  on my Windows machine (VM host) and computed the SHA256 hash, I got the exact hash that apt printed as the expected value. This led me to believe that the error was not with the mirror but with my VM.  The next thing I tried was wget https://mirrors.ocf.berkeley.edu/kali/dists/kali-rolling/main/binary-amd64/Packages.gz followed by sha256sum Packages.gz, which provided yet another different hash output.  To be clear, I have seen 3 different hashes for the same file:   The "correct" hash shown by apt as expected, which is the one that windows also produced after downloading the file using a browser The incorrect hash calculated by apt, which led to the error A different hash calculated by sha256sum after downloading the file using wget using the same URL as for the browser download   I should also note that I have only been referencing the SHA256 hash in each step. The other hash functions are also mismatched when I run sudo apt update, but the file size is the same. I had considered that downloads might be failing due to limited disk space (it is a VM after all) but I don't think that's the case.  What am I missing?


Two tubes (infinite right circular cylinders) $A$ and $B$ of equal radii $3$ cross at the angle $90°$ (i.e. their axial lines cross at that angle). What is the volume of the intersection of $A$ and $B$? I figured it should be equal pir22r but just to cross check.


Can anybody show me how to prove that $\cos^2(z)+\sin^2(z)=1$ for $z\in \mathbb{C}$? I can prove it for the case where $z$ is real, but can't seem to find a way to prove it for complex numbers in general.


Do the cards in the shop depend on the arena you are in when the shop refreshes?

Will cards from a higher arena than you appear in the card shop, or will only cards from the arena you are in (or below) when it refreshes be available to purchase?


Let $p$ be a prime number. Find all $p$'s such that $p^4 + p^3 + p^2 + p +1$ is a perfect square.   I tried rewriting the expression as  $p^4 + p^3 + p^2 + p +1 = x^2 \iff (p^2 + p)(p^2 + 1)=(x - 1)(x + 1)$. Then I think I need to bound this using $x$ but am not sure how to.


Find an integer $y$ such that $x= (ay+b)/c$ is also an integer

Given three fixed integers $a,b,c$. I am asking if one can find an integer $y$ such that the quotient $$x= (ay+b)/c$$ is also an integer. There is no restriction on the values of $y$.


Find $$M:=\sum_{n=1}^{\infty}\tan^{-1}\frac{2}{n^2}$$   There's a solution  that uses complex numbers which I didn't understand and I was wondering if the following is also a correct method.   My proposed solution   $$\begin{align} &\sum_{n=1}^{\infty}\tan^{-1}\frac{2}{n^2}\\ =&\sum_{n=1}^{\infty}\tan^{-1}\frac{(1+n)+(1-n)}{1-(1+n)(1-n)}\\ =&\sum_{n=1}^{\infty}(\tan^{-1}(1+n)+\tan^{-1}(1-n))\\ =&\sum_{n=1}^{\infty}(\tan^{-1}(n+1)-\tan^{-1}(n-1)) \end{align} $$  And this implies  $$M=\lim_{m\to\infty}(\tan^{-1}(m+1)+\tan^{-1}m-\tan^{-1}1-\tan^{-1}0)=\frac{3\pi}{4}$$