I have problem, i have coded some simple if statement on beggining of the code that looks like this:     manager.on('sentOfferChanged', function(offer, oldState) {  if (TradeOfferManager.ETradeOfferState[offer.state] === "Declined") {   var ifvartruefalse = false;   return; } if (offer.itemsToGive.length == 0){     if (offer.state == TradeOfferManager.ETradeOfferState.Accepted){      var ifvartruefalse = true;     }   } });  Then I am trying to call that var from these if statements to tell me if its true or false inside another if statement:                                                     if (ifvartruefalse == false){                                                     message.reply('<:false:750799883572609245> **Trade was declined, deleting the coinflip**');                                                     return                                                   }                                                      if (ifvartruefalse == true){                                                     message.channel.send('<:true:750799921497505913> **Trade was succesfully confirmed**, generating random ticket from 0 to 100');  And keep getting error that ifvartruefalse is not defined. Please someone help...

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I know that you can use .next() in jQuery to get the next element but I also know that you can give an argument, like a selector, and it will give you the next element that matches the given argument but in my case it doesn't work. Example: HTML:

                  Google  JS: let div = $("div#divTEST");  console.log(div.next()); console.log(div.next("a"));  Now, the problem is not the div.next(), since I get the 'span' element back, the problem is div.next("a") because it doesn't give me anything in return. What am I doing wrong ?

I want to find the first span element after class counter, in code something like this:

    It seems like the next() function only finds the immediate next element, so something like this:  $(".counter").next("span")   Won't work. The way I have been using is a bit lengthy and I was wondering if there was a shorter way, it is this:  $(".counter").nextAll("span").eq(0)   I think the closest() method in jQuery 3 will do the trick, but I am using 1.2.6 -- is there a better way to do this (am I just using next() wrong?)


$x!+1=y^2$, I found 3 solutions. They are $(4,5),(5,11),(7,71)$. Is there a $4$th solution?If not can you prove it?

One observes that  \begin{equation*} 4!+1 =25=5^{2},~5!+1=121=11^{2}  \end{equation*} is a perfect square. Similarly for $n=7$ also we see that $n!+1$ is a perfect square. So one can ask the truth of this question:   Is $n!+1$ a perfect square for infinitely many $n$? If yes, then how to prove.


Let $R$ be a commutative ring with identity, let $N = \{x|x \in R, x^k=0$ for some natural number k$\}$, and let $L = \{x|x \in R, 1+xr$ invertible for all $ r \in R\}$.  I am trying to find an example of a ring R such that $N$ is strictly smaller than $L$.    It is not hard to show that $N \subseteq L$ and so I have reduced this to finding an element in R that is in $L$ but not in $N$.  It seems like $R=$ the real numbers might work, since for example $a \in R$ is in $L$ since $(1+ar)(\frac{1}{1+ar})=1$ but $a^k \neq 0$ for any natural number k if $a \neq 0$.  I'd appreciate any help with this since I'm not sure whether or not I'm on the right track here and most of the other rings such as $Z/nZ$ I've considered don't seem to have this property.  Thanks!

In a preparation question for an exam, I am asked to give an example of a ring $A$ such that the nilradical $\operatorname{Nil}(A)$ is strictly smaller that the Jacobson radical $J(A)$. Here's how I solved the problem:  It is enough to find some ring $A$ with a prime ideal $p$ which is strictly contained in some maximal ideal $m$. Then the localization $A_m$ is a local ring with maximal ideal $m$, and by the correspondence between ideals of $A_m$ and ideals of $A$ contained in $m$ we have that $J(A)=m\supsetneq p\supset\operatorname{Nil}(A)$.  An example is $A=\mathbb{Z}[x]$, $p=(x^2+1)$ and $m=(x^2+1,2)$.  Now I was wondering: are there also any "elementary" examples satisfying the condition above? By this I mean basically examples where I don't have to localize the ring.


I was thinking about how asteroids get "burned" up in the upper atmosphere as they approach the earth surface due to the atmosphere of earth heating the asteroids immensely as a result of air compression which is nothing strange.  This however seems opposite of things I observe day to day. While I am travelling in my car I open my window, and to my surprise the car became very chilly and I develop goosebumps (body response to cold), so I am inclined to think that the temperature of my body dropped slightly as a result of me travelling in our Air.    This creates a sort of paradox, for a person travelling at asteroid-speeds s\he would say that as we speed up we heat the objects up, but for a person who travels at day-to-day speeds they would say as we increase in speed we cool things down, but both cannot be correct so who is correct?  So my question is at what speed does temperature raise and not fall as we travel through air? And if so why is that?

I understand that air friction cools off an object at low speeds. For example, if you blow on a spoon of hot soup, it cools off. Or if you swing a hot frying pan in the air, it cools off faster.  But at higher speeds, the situation changes in the opposite. For example, consider a meteor falling on Earth. It is so fast that it heats up to such a high temperature that it burns into ashes.  What is the critical speed in which an object starts to heat up?  For example, consider a spherical object with radius of 1 meter. Let its density be 1 g/cm3 if needed. And let the air pressure be 1 atm. Assume that the temperature of the object is 400 K and the temperature of the air is 300 K. Also assume that the specific heat constant of the material is 1 cal/(gr.K). What is the critical speed for this object after which its temperature starts to rise above 500 K?


how to make div with class boxLinks = bottom in the main box = class = main-box?  my idea   this class main width 1200px; this class main-box are 5 div, every div width 25%     .main-box {   width= "25%";   float= left; }

          <button> PRESS </button>

     i want this div boxLinks in the last div,

Given the following HTML:

     Copyright Foo web designs

    I would like #copyright to stick to the bottom of #container. Can I achieve this without using absolute positioning?


I've been across this on the web:  \begin{align} \frac{0}{0} & = \frac{100-100}{100-100} \\ & = \frac{10^2-10^2}{10(10-10)} \\ & = \frac{(10-10)(10+10)}{(10)(10-10)} \\ & = \frac{(10+10)}{10} \\ & = \frac{2}{1} \\ & = 2 \end{align}    Of course this is wrong but I can't tell where exactly since there is no obvious (to me at least) atrocity... Is this in the first line $ \frac{0}{0} = \frac{100-100}{100-100}$ ?

I was mathematically shown 1 = 2 by a function that states the following  $$x^2-x^2 = x^2-x^2 $$   $$x(x-x)=(x-x)(x+x)$$  dividing by $(x-x)$ we get...  $$x=x+x$$     $$ x=2x$$      $$1=2$$  I can see that mathematically he was right, but for sure that I was missing something as it doesn't make mathematical sense


We are traveling from Spain to Canada via Portugal. The flight we purchased was to  depart on March 14th from Spain, with a 2-hour stopover in Lisbon. The last leg of the flight is Lisbon to Toronto. Both flights are with the same carrier.  We have been advised that the first flight was cancelled and rescheduled for the 13th. This will require us to stay overnight in Lisbon. They advise that they are not responsible for any expenses and no other flights are available.   It just doesn't seem right; is it?

I have been researching this for some time now, but can't seem to find a definite answer to my worries.   In May '15 I booked a ticket through a travel agent for the trip: Rio de Janeiro-->Madrid, Madrid-->Copenhagen (in February '16). Both flights are with IBERIA/IBERIA EXPRESS. In September '15 I got an email from IBERIA that the departure of my connecting flight from Madrid to Copenhagen had been changed to the next day, which gives me a layover time of about 25 hours in Madrid.   What are my rights? Can I make them pay a hotel, can I get a refund, can I make them pay another connecting flight?


I have been watching Hocus Pocus and wondered how people in the 1800s knew when to add eth on the end of words.

What happened to them, and how were they once used? Straining my mind to sound archaic, I came up with the following:     Dost thou thinkest thou can escape thy sins?   and     Bringeth me mine armor and favorite sword.   I’d like to use these suffixes intelligently, so my questions are: how are ‑est and ‑eth properly appellated in conjugations, and  when and why did they disappear?


I need to remove the background from this image. Is there a trick to removing the background from between/behind the cage part without having to go into each section? The floor, wall and cord will be removed, all else needs to stay. Using the latest version of Photoshop.     Thanks.

Is there any way in Photoshop to remove a background color from an image, when some of the background is behind a transparent object.   So far, I've tried using masks and channels but have not made any progress. I want to make the background transparent, so that the bottle and 'ink' can be put onto a white background colour.  Many thanks in advance, any help would be much appreciated.


I don't understand how to use Fermat's little theorem to find remainders e.g if we are asked to find remainder of 50^50 on division by 13, what is a and what is p in the formula? What is going on?? Are we using congruence classes when using Fermat's little theorem? Can someone please give me a step by step explanation from the beginning, I'm  just not understanding this stuff.

I don't understand how to use Fermat's little theorem to find remainders e.g if we are asked to find remainder of $50^{50}$ on division by $13$, what is a and what is $p$ in the formula?  Also I wanted to check can we use both congruence classes as well as Fermat's little theorem to find such remainders? How would be write $50^{50}$ on division by $13$ in terms of congruence classes to find the remainder?  I don't exactly understand what a congruence class is, what does it tell us and how is it related to this?


Occasionally (very occasionally) when returning to the main page of a site by clicking on the logo I get the following message:     It was not possible to perform this tag search at this time due to an unexpected error.   This is odd because I'm not performing a tag search.  So far this has happened on both Movies & TV and Cooking.  I have heard that others are getting this same message.

I browsed MSE front page a minute ago, and was greeted with the following error message:     It was not possible to perform this tag search at this time due to an unexpected error.   Screenshot:        I did not search for any tags...  Can the message please be changed to something more meaningful?


Is it correct to write: "What methodologies are implemented " or "Which methodologies are implemented"?   I did a little research and found both. Is there a rule? I personally think "what" sounds strange, but can't apply anything on it.  For the usage in a paper.

Most of the time one or the other feels better, but every so often, "which" vs. "what" trips me up.   So, what's the exact difference and when should you use one or the other?


How can I tell shell to re-read the ~/.bashrc without restarting the shell?

Is it possible to coerce bash to reload the .profile file without logging out and back in again?


I am trying to implement data structure Linked List (Singly) however by adding elements returns NULLPOINTEREXCEPTION.  import java.util.NoSuchElementException;  public class Linkedlist<ANYTYPE>{  private Node head;  Linkedlist(){     head = null; }  public void add(ANYTYPE data){     head.next = new Node<>(data, head); }  public void traverse(){     if(head == null) throw new NoSuchElementException("List may be empty");      Node temp = head;      while(temp != null){         System.out.println(temp.data+" ");         temp = temp.next;     } }  public static void main(String[] args) {      Linkedlist<String> l=new Linkedlist<String>();     l.add("one");     l.add("two");     l.traverse(); }   private class Node<ANYTYPE>{      private ANYTYPE data;     private Node next;      Node(ANYTYPE data, Node next){         this.data = data;         this.next = next;     } }  }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I was practicing the use of wildcards today .. that was a lot of fun.  The most complex thing that worked out exactly as I was expecting was:  ls [![:digit:]]*[a-z][0-9][0-9][0-9][aA-zZ]*[![:digit:]]   But I didn't actually manage to exclude a string.  How can I list only files which do not contain "test"?  Here some examples what I've tried already: ls *!("test")* ls !("test") ls !=*"test"* ls !(*"test"*) ls *^test* ls *(^test)* ls (^test)* ls !test* ls !*test* ls *!test* ls !{test} ls !*{test}* ls *!{test}*

I have several files with the same base filename. I'd like to remove all but one  foo.org #keep foo.tex #delete foo.fls #delete foo.bib #delete etc   If I didn't need to keep one, I know I could use rm foo.*.    demonstrates ^ to negate a match. Through trial and error, I was able to find that  rm foo.*[^org]   does what I need, but I don't really understand the syntax.   Also, while not a limitation in my use case, I think this pattern also ignores foo.o and foo.or. How does this pattern work, and what would a glob that ignores only foo.org look like?


I'm trying to use git rebase for changing a commit, but when I'm in the console inside the rebase comand if I try to use the arrow keys I get A, B, C or D letters. I created the .vimrc file with the line set nocompatible in case that was the problem but no luck... What am I missing?

When I tried to use arrow keys in insert mode in vi editor the following characters are being inserted in the editor:   for ↓ I get B, for ↑ I get A, for ← I get D, for → I get C.   Please help me in resolve this problem.


I know this is (one of the) proper ways to create an Array of Objects in PHP:  $obj1 = new stdClass; $obj1->title = "Title 1"; $obj1->author = "Author 1"; $obj1->publisher = "Publisher Name 1";  $obj2 = new stdClass; $obj2->title = "Title 2"; $obj2->author = "Author 2"; $obj2->publisher = "Publisher Name 2";  $obj3 = new stdClass; $obj3->title = "Title 3"; $obj3->author = "Author 3"; $obj3->publisher = "Publisher Name 3";  $newArray = array($obj1, $obj2, $obj3); echo ($newArray[0]->title);   but in some other languages (JS,  ActionScript..etc) you can quickly create the object inside the array declaration like so:  var userArray = [{name:'name 1', age:'10'}, {name:'name 2', age:'11'}, {name:'name 3', age:'12'}];   generic, not named, no class objects.....  And then access it like so:  userArray[0].name    Is there a quick/shorthand way in PHP to do the same?  Or do you need to define an object name and instantiate it..etc  Like so: $obj1 = new stdClass;  and then move to assigning each property and then add to the array all in separate steps?

In javascript you can easily create objects and Arrays like so:  var aObject = { foo:'bla', bar:2 }; var anArray = ['foo', 'bar', 2];   Are similar things possible in PHP? I know that you can easily create an array using the array function, that hardly is more work then the javascript syntax, but is there a similar syntax for creating objects? Or should I just use associative arrays?  $anArray = array('foo', 'bar', 2); $anObjectLikeAssociativeArray = array('foo'=>'bla',                                       'bar'=>2);   So to summarize: Does PHP have javascript like object creation or should I just use associative arrays?


In econometrics, while using Newton Raphson algorithm, why do we use 2nd Order Taylor Expansion, what is the requirement or intiution behind it? Is it something related to convergence issue? Can someone show analytically?

I've googled this and I've seen different types of proofs but they all use notations that I don't understand.  But first of all, I need to understand what quadratic convergence means, I read that it has to   do with the speed of an algorithm. Is this correct?  Ok, so I know that this is the Newton-Raphson method:  $$x_{n+1}=x_n-\dfrac{f(x_n)}{f'(x_n)}$$  How do I prove that it converges?  Thanks.


I want to know the difference between 'I know swimming.' and 'I know to swim.' Do native speakers understand the meaning of the sentence 'I know to swim.' I didn't see the sentence like 'I know to swim.' but I think that(I know to swim) is a right sentence grammatically. Is the sentence (I know to swim.) not acceptable but understandable by a native speaker?

I was reading a website where common English sentence errors are written -     INCORRECT - He doesn't know to swim.      CORRECT - He doesn't know how to swim.   I know He doesn't know how to swim is a correct sentence. But why is the other one wrong, is my question?  I know that know is a transitive verb. So, the following are correct -   i) He knows swimming.  Swimming is a gerund. We can also use the infinitive form here - to swim  ii) He knows to swim.


I have the Realtek rtl8723be driver on my HP-Pavillion Notebook.  While installing Ubuntu 18.04 LTS through plug-n-play option, I tried the following commands before actual installation:  sudo modprobe -r rtl8723be sudo modprobe rtl8723be ant_sel=2   and the wifi was working just fine.  But after installation alongside Windows 10, somehow the wifi stopped working properly, and now only wifi networks very close to the device appear.  I tried installing realtek software from  as mentioned in the README. But still no progress.   I even tried changing ant_sel parameters, then saving them to my /etc/modprobe.d/rtl8723be.conf and then performing a cold boot. But still no progress.  I also tried installing from , but I got errors.  sudo lshw -class network   *-network                         description: Wireless interface        product: RTL8723BE PCIe Wireless Network Adapter        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:08:00.0        logical name: wlo1        version: 00        serial: 70:77:81:bf:a7:b9        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless        configuration: broadcast=yes driver=rtl8723be driverversion=4.15.0-36-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11        resources: irq:18 ioport:5000(size=256) memory:c6100000-c6103fff   *-network        description: Ethernet interface        product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:09:00.0        logical name: eno1        version: 0a        serial: 3c:a8:2a:ba:12:6f        size: 10Mbit/s        capacity: 100Mbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8107e-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=MII speed=10Mbit/s        resources: irq:19 ioport:4000(size=256) memory:c6004000-c6004fff memory:c6000000-c6003fff   *-network        description: Ethernet interface        physical id: 3        logical name: enp0s20u2        serial: ea:f8:17:e8:82:30        capabilities: ethernet physical        configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.6 link=yes multicast=yes   Can anyone suggest what to do now?

I have a HP 14-AN001NA laptop. It came with Windows 10 installed on which the Wi-Fi worked fine anywhere in the house.   However I removed Windows 10 and installed Ubuntu 16.04 instead and since I have had terrible Wi-Fi anywhere aside from about three foot away from the router. I don't know if it's relevant but my Wi-Fi is not called wlan0 but wlo1 for some reason (I didn't change it).  When running lspci -knn | grep Net -A3     I get the following output:  05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723] DeviceName:   Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:81c1] Kernel driver in use: rtl8723be Kernel modules: wl, rtl8723be


I have read many articles about roc curve and how it works. But im still confused. Can someone please explain me what the points 5, 7, 9 means in the picture below?

I have a ROC curve like the figure below:   What can be inferred given this kind of curve in general?  What are the differences of states 1, 2 and 3 in the figure?  What causes the diagram to jump straight from state 1 to state 3? Most of the ROC curves on the internet look like the figure below:


I've got a folder (Projects) on my local windows 7 computer. It's shared through Google Drive. I want to take some of the subfolders and make them Local-only.  I tried going to Google Drive options (on my PC) and unchecking SubFolderName. However, that just removed it from my local folder.

Using Google Drive on Windows (although I think the same question applies to OS/X) I want to exclude certain local folders but keep them on the computer.  When I go to Drive preferences and deselect specific folders, it wants to remove them from the local PC and keep them only in the cloud.  This doesn't work for me.  I feel like I could do this in earlier versions of the Google Drive client but I cannot recall for sure.  Is this possible?


Scanner s = new Scanner(System.in);   String x;    do {      x = s.next();      System.out.println(x);      if (x == "1") {         System.out.println("working");      }   } while (x != "2");   This code prints the correct value of String x, but will never print "working" and does not end the do/while loop when x == 2. What is wrong with this code?

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


I want to use a relay switch with the GPIO on my raspberry pi 2 (40 pins).  I found the link below on google and it mostly makes sense, what I'd like to know is why do I need to use a transistor to activate the relay switch?  why can I not just wire it up directly?    please keep in mind I am a novice with electronics.  Thank you :o)

I'm trying to control a solenoid using the RasPi 2's GPIO pins. Since the solenoid needs more power than the RasPi can provide, I'm using a 9V battery to provide the power.  I started with just wiring the circuit and checking if it works by connecting and disconnecting the 3v3 output to the board.  First, here's the wiring I'm currently using:    The diode accross the solenoid inputs is a standard flyback diode, and the resistor is a 1kOhm resistor.  Apparently the RasPi GPIO output pins produce 3.3V at a maximum draw of 16mA.  The inductor represents my solendid, which I got from . As far as I can tell, it requires 12V / 1A to operate, but connecting the 9V battery straight to it (skipping the transistor) works nicely enough. Even the RasPi 5V output provides a weak activation.  However, when going through the transistor, the solenoid does not activate properly. I have noticed that when the base pin is on though, it will "hold" the end position if pushed manually, just not push towards there by itself. It does not do this if the base pin is not connected.  I tried using a BC547 NPN transistor, then I figured the output current was not enough, so I switched to a BC639 (which should have up to 1-1.5A current output), but that didn't help either.  My question is, what transistor should I use? Am I doing anything else wrong? I've seen other people use a TP120, which seems to have an even higher output current.  Since I'm setting up a circuit with 24 of these, I'd like to know for sure before ordering another batch of transistors.


test.sh:  #!/bin/bash export test_var=1   Run the script, then continue to run the command in the terminal: echo $test_var, I got nothing. Why? Since test_var was exported, I thought I could continue to use the variable in the terminal.

I have a bash script which must call another bash script which varies per-user in order to get some configuration information, like so:  somescript:  #!/bin/bash ${HOME}/.ssconfig echo "Hello, ${VARIABLE}!"   ~/.ssconfig  #!/bin/bash VARIABLE=world   Which, instead of giving me Hello, world! as expected, gives me Hello, ! How can I pass variables up from a script to the one that called it?


I got an email this morning that myOpenID is ending Feb 2014.  How anyone else received this?  Is it real?  If so, what login do I use for stackexchange/stackoverflow?  Is there a way to migrate/transfer into another login so I don't use all of my reputation points?

Sometimes OpenID providers end their services, like  and  did. How do I add or remove login methods so I don't get locked out of my Stack Exchange account?     For more information, see  in the Help Center.


Does anyone know how White Walkers were created and why? Or who they were created by?

Just watched the 4-th episode of season 4. In the end we see the scene where      the baby is turned into one of the white walkers by a magic ritual.   That means that      The white walkers actually aren't immortal, they grow older over the time, and they perhaps even can die from old age.   But if that's how the process of reproduction is organized for the White Walkers, that brings the question:  Who was the first white walker ever and how did he come to such a state?


If i cant my laptop to the side the display turns in this direction. I dont need that because I have no touchscreen. How can I disable that? My system: HP Probook 650 G2 Ubuntu 18.04  Thank you Raphael

In Ubuntu 17.04 there was 'Rotation' menu in Display tab. But now in new version of Ubuntu, there's still a Display tab but no more rotation menu. Now I can't turn that off again since I upgraded to 18.04 LTS.


I read some documentation about how to create a new shape. But some things are still not clear to me. In fact I wanted to create a new shape representing a switch symbol: I did the code in tikzpicture environment. Here is the code:  \documentclass{article}  \usepackage{tikz} \usetikzlibrary{shapes, arrows, fit} \begin{document}  \newcommand\switch[0] {     \begin{tikzpicture}         \draw (0, 0) -- (1, 0) (1, 1) -- (2, 0) -- (3, 0);         \draw [->, thick] (2, 1) .. controls +(left:5mm) and +(up:5mm) .. (1, 0);     \end{tikzpicture} } \switch \end{document}   Any suggestion is welcome.

If I have two tikzpictures drawn:  \documentclass{article} \usepackage[margin = 1in]{geometry} \usepackage{tikz} \usetikzlibrary{decorations.pathmorphing,calc,shapes,shapes.geometric,patterns} \begin{document}  \tikzset{treetop/.style = {decoration={random steps, segment length=0.4mm},decorate},trunk/.style = {decoration={random steps, segment length=2mm, amplitude=0.2mm},decorate}}  \begin{tikzpicture} \foreach \w/\f in {0.3/30,0.2/50,0.1/70} { \fill [brown!\f!black, trunk] (0,0) ++(-\w/2,0) rectangle +(\w,-3); } \foreach \n/\f in {1.4/40,1.2/50,1/60,0.8/70,0.6/80,0.4/90} {    \fill [green!\f!black, treetop] ellipse (\n/1.5 and \n); } \end{tikzpicture}  \begin{tikzpicture} \shade[bottom color=cyan!60!black, top color=blue!20!white] (0,0) rectangle (10,10); \end{tikzpicture}  \end{document}     How could I use the first tikz picture within the second? Can I define the first picture as some variable and then place this variable within the second picture and have the option of defining its exact location (x,y) and its size? For example, if I wanted to place the tree in the middle of the rectangle (5,5) but make the size of the tree half its current size. How would I do this


I was reading a text and this was the proof that they provided:     Clearly Aut(G) is a subset of Sym(G); we need to check that it is a   subgroup. Certainly the composition of two automorphisms is an   automorphism, and it is easy to check that the inverse of an   automorphism is an automorphism.   I don't understand it so any proof better than this would be appreciated.

I have to prove that if G is a group, Aut(G) is a subgroup of Sym(G), and later that the inner automorphisms group is a normal subgroup of Aut(G). I have time until tomorrow in the morning, but I have no idea what to do, please please please help me.


What's a word or phrase for a situation in which, for example, people in authority pretend to be serious in selecting a new member, whereas they have already decided who to choose?  I googled it but to no avail.

I want to write about the Chinese Government during the Cultural Revolution and argue that whilst they created the appearance of more political openness, it was merely a façade.  Is there a word that expresses the inauthenticity of their actions? Like the 'falseness' of their policies but referring specifically to the fact that they pretend to be something they're not and that they hide something more sinister.


Let $R$ a commutative ring (with $1$) such that $x^2=x$ for all $x\in R$.  Prove that for every $x,y\in R$ exist $z\in R$ such that $\langle x,y\rangle=\langle z\rangle$  Any idea with this? the exercise had an item a) that said to prove that $2x=0$ for all $x\in R$, but I can't see how to use it.

The classical book on commutative algebra Introduction to Commutative Algebra, by Atiyah and Macdonald, has the following as exercise I.11.       A ring is Boolean if $x^2=x$ for any $x$ of $A$. In a Boolean ring $A$, show that     i) $2x=0$ for all $x\in A$;    ii) Every prime ideal of $A$ is maximal, and its residue field consists of two elements;   iii) Every finitely generated ideal of $A$ is principal.     I can but solve the first two of them; for the last one, I cannot even perceive the situation here, for it will not, generally speaking, be a Dedekind domain, whereof my knowledge is somewhat more. I have hitherto tried to find one element for each ideal of two generators which can stand the stead of them, and then proceed by induction. But even the first step fails to produce any result. Thanks for any hints and inspirations in advance.


OS Operating system    FreeDOS Processor Processor   Intel® Core™ i5-4210U with Intel HD Graphics 4400 (1.7 GHz, 3 MB cache, 2 cores) MEMORY Memory, standard    4 GB 1600 MHz DDR3L SDRAM (1 x 4 GB) STORAGE Hard drive description  1 TB 5400 rpm SATA OPTICAL DISK DRIVE Optical drive   SuperMulti DVD burner GRAPHICS Graphics    NVIDIA GeForce 820M (2 GB DDR3 dedicated) Display Display size (diagonal)     15.6" Display     15.6" diagonal HD BrightView LED-backlit (1366 x 768) Connectivity Expansion slots     1 multi-format SD media card reader Network interface   Integrated 10/100 BASE-T Ethernet LAN Wireless    802.11b/g/n (1x1) and Bluetooth® 4.0 combo Ports/Slots Ports   1 USB 3.0; 2 USB 2.0; 1 HDMI; 1 RJ-45; 1 headphone/microphone combo INPUT Webcam  HP TrueVision HD Webcam (front-facing) with integrated digital microphone Pointing device     Touchpad with multi-touch gesture support Keyboard    Full-size textured island-style with numeric keypad Audio Audio features  Dual speakers POWER Power supply type   65 W AC power adapter Battery type    4-cell (41 WHr) Li-ion SECURITY Security management     Kensington MicroSaver lock slot; Power-on password; Accepts third-party security lock devices MACHINE DIMENSIONS & WEIGHT Weight  Starting at 2.23 kg Minimum dimensions (W x D x H)  37.8 x 25.9 x 2.53 cm

I'm looking to download and install the latest version of Ubuntu to replace the current version of Windows I had pre-installed on my machine when bought it.   I have some really neat features on the machine that I really am hoping will still work when I move over to Ubuntu.  Can someone please confirm if the below will still work and, if not, how I can get them to work:   The USB ports on my machine The ethernet or Network work port on the machine The HDMI output on the machine and finally, the built in webcam   Thanks Sam


how do i convert  2345 in to 2.345,00 the right way?  converting 2345 in to 2345.00 is easy as:  var new = parseFloat('2345').toFixed(2);   Have i to work with substrings or are there functions for formating floats in to UK notation?

I would like to format a price in JavaScript. I'd like a function which takes a float as an argument and returns a string formatted like this: "$ 2,500.00"  What's the best way to do this?


I was trying to write a program which would give me a message when something (xx) in this case is typed, but it doesn't print a message. Can you please tell me why that happens ?  I've also checked the code if it's equal to xx when I type it, and it is.   import javax.swing.*; import java.awt.*; import javax.swing.text.*; import javax.swing.event.DocumentEvent; import javax.swing.event.DocumentListener; class acc { public static void main(String[] args) { ramka ramka = new ramka(); panel panel1 = new panel(); ramka.show(); ramka.add(panel1); } } class ramka extends JFrame {   public ramka()  {   setSize(800, 600);      setTitle("Super duper programer");   Container kontener = getContentPane();   textfield pole = new textfield();   kontener.add(pole);   setDefaultCloseOperation(EXIT_ON_CLOSE);     sluchacz listener = new sluchacz();   pole.getDocument().addDocumentListener(listener);  }  } class panel extends JPanel {  public void paintComponent(Graphics g)     {   super.paintComponent(g);  } } class textfield extends JTextField {  } class sluchacz implements DocumentListener  {   @Override   public void changedUpdate(DocumentEvent e)   {}    @Override     public void removeUpdate(DocumentEvent e){}   @Override       public void insertUpdate(DocumentEvent e)            {           try           {          String input = e.getDocument().getText(0, e.getDocument().getLength()).trim(); if(input == "xx") {     String message = JOptionPane.showInputDialog("You've just typed ''xx''"); }     }      catch(BadLocationException ex)      {         }           } }

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


Many country and airline cancel airplane travel from/to China because corona virus. This force many people from China over stay their visa. Will countries extend their visa?

A friend of mine is currently in Wuhan, China, as   He is a European citizen and had thus made a tourist visa to visit the family of his wife for the Lunar new year, but got caught in the middle of the quarantine and lockdown of the city as he is bound to leave soon. He has an extended visa and all is fine for him, but this situation got me thinking:  Say somebody is travelling to a city like Wuhan, and they should leave tomorrow to go back home and their visa is about to expire and the city unexpectedly is locked down under quarantine.   What would this somebody situation be ? Would they be illegally in the country ? Is there some special law that covers these situations or is it an international agreement ?   Just to clarify, I am asking this question just out of pure curiosity, I am not currently in this situation.


Let $r$, $s$, and $t$ be positive integers greater than $1$. How to prove that  there exists a finite group $G$ having elements $x$ and $y$ such that $x$ has order $r$, $y$ has order $s$, and $xy$ has order $t$?  Thanks in advance.

I am struggling with the following problem:     Find a group $G$ such that whenever $m, n, k \geq 2$ are natural numbers, then there exist $a, b \in G$ such that the order of $a$ is $m$, order of $b$ is $n$, and order of $ab$ is $k$.   The group $G$ necessarily has to be non-commutative and infinite.


I have just recently installed Ubuntu into my pre installed Windows 10 machine but since I installed Ubuntu in my unallocated free space Windows doesn't recognize it as a separate drive so when booting it just loads the Windows OS straight.   How can this be rectified?

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


I have a problem :  There are 6 men and 5 women who will sit in a circular table. How many ways they sit where no two women sit next to each other?  I have tried to work for it and get the result $5!*5!$, where the first $5!$ represents the number of ways men sit and the second $5!$ is the number of ways to permute the women,  but I am not so sure. Help please

Can someone please explain how to solve circular permutation sums. I just cannot seem to understand them.    eg.       $\text{(4)}$ The number of ways in which $6$ men and $5$ women can dine at a round table if no two women are to sit together is given by          $\text{(a)}$ $6!*5!$   $\text{(b)}$ $50$   $\text{(c)}$ $5!*4!$   $\text{(d)}$ $7!*5!$


I'm new to LaTeX. When I'm learning how to use it, I'm always having trouble searching the meaning of some commands, such as \thechapter, \chaptertitlename... I think these must be basic commands in LaTeX but I cannot figure out what EXACTLY they are used for. Someone suggest me to check texdoc, however I didn't find the explanation of what I want either(I searched for the commands name in the doc). Is there some other resource that I can refer to? Or am I using wrong way of reading texdocs?

Which book (free or otherwise) was the most useful to you when you started learning LaTeX?  I am frequently asked this question by friends who want to learn LaTeX, and I recommend the book which got me started, , but I feel that there might be better options around.  Also see .


Ubuntu 14.04 LTS is the only OS on my laptop. I have spent alot of time researching on how to format the drive along with Ubuntu OS. Kindly help me do this.

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


Given file path, how can I determine which process creates it (and/or reads/writes to it)?

Three files have suddenly appeared in my home directory, called "client_state.xml", "lockfile", and "time_stats_log". The last two are empty. I'm wondering how they got there. It's not the first time it has happened, but the last time was weeks ago; I deleted the files and nothing broke or complained. I haven't been able to think of what I was doing at the time reported by stat $filename. Is there any way I can find out where they came from?  Alternatively, is there a way to monitor the home directory (but not sub-directories) for the creation of files?


In computing a cross section for the mutual scattering of two electrons (Zee, Sec II.6), I have gotten the expression factorized so that it contains a term \begin{align*}  \tau^{\mu\nu}&=\frac{1}{2}\sum_s\sum_S\,\bar u(p,s)  \gamma^\mu  u(P,S) \bar u(P,S)\gamma^\nu u(p,s) ~~. \end{align*} I want to simplify with \begin{equation*}  \sum_s u_\alpha(p,s)\bar u_\beta(p,s)=\left(\frac{\gamma^\mu p_\mu+m}{2m}\right)_{\!\alpha\beta}~~. \end{equation*} My first step is two rewrite $\tau^{\mu\nu}$ with matrix multiplication indices so that I can group the two outer spinors as required for the identity.  This yields \begin{align*}  \tau^{\mu\nu}&=\frac{1}{2}\sum_s\sum_S\,\bar u_\alpha(p,s)  \gamma^\mu_{\alpha\beta}  u_\beta(P,S) \bar u_\sigma(P,S)\gamma^\nu_{\sigma\rho} u_\rho(p,s) ~~. \end{align*} By moving the $u_\rho$ on the right over to the far left, I obtain \begin{align*}  \tau^{\mu\nu}&= \frac{1}{2\big(2m\big)^2}\,\big( \gamma^\lambda p_\lambda+m \big)_{\!\rho\alpha}  \gamma^\mu_{\alpha\beta}  \big( \gamma^\kappa P_\kappa+m \big)_{\beta\sigma}\gamma^\nu_{\sigma\rho} ~~. \end{align*} Zee says this is equal to \begin{align*}  \tau^{\mu\nu}&= \frac{1}{2\big(2m\big)^2}\,\text{tr}\big( \gamma^\lambda p_\lambda+m \big)  \gamma^\mu \big( \gamma^\kappa P_\kappa+m \big) \gamma^\nu  ~~, \end{align*} but I am not seeing how this trace epxression follows.  Any pointers?

I've been studying different scattering processes (from Mandl & Shaw QFT's book, chapter 8) and there's always a purely-mathematical common step I do not understand: the showing-up of the trace. Let me give two specific examples.  $$A_{(l) \alpha \beta}=\sum_{s_1} \sum_{s_2} \Big[ \bar u_{s_2} (\vec p_2') \gamma_{\alpha} v_{s_1} (\vec p_1'))(\bar v_{s_1}(\vec p_1')\gamma_{\beta} u_{s_2} (\vec p_2'))\Big]_{(l)}=Tr\Big[\frac{\not{\!p_2'}+m_l}{2m_l} \gamma_{\alpha} \frac{\not{\!p_1'}-m_l}{2m_l}\gamma_{\beta}\Big] \ \ \ \ (1)$$  $$X= \frac 1 2 \Lambda_{\delta \alpha}^+ (\vec p') \Gamma _{\alpha \beta} \Lambda_{\beta \gamma}^+ (\vec p) \tilde \Gamma _{\gamma \delta}=\frac 1 2 Tr \Big[\Lambda^+ (\vec p') \Gamma \Lambda^+ (\vec p) \tilde \Gamma \Big] \ \ \ \ (2)$$  Where:   $\not{\!A} := \gamma^{\alpha} A_{\alpha}$ $\Gamma$ is a $4 \times 4$ matrix $\tilde \Gamma := \gamma^0 \Gamma^{\dagger} \gamma^0$ $u, v$ are the Dirac Spinors (which are $4 \times 1$ matrices) The Dirac-$\gamma$-matrices are $4 \times 4$ matrices and the adjoint is defined as $\bar w := w^{\dagger}\gamma^{0}$ $\Lambda^+$ is the positive energy projection operator defined as  $$\Lambda_{\alpha \beta}^+ (\vec p) := \Big( \frac{ \not{\!p}+m}{2m} \Big)_{\alpha \beta}$$ $\Lambda^+$ has the following property   $$\Lambda_{\alpha \beta}^+ (\vec p) = \sum_{r=1}^2 u_{r \alpha} (\vec p) \bar u_{r \beta} (\vec p)$$  But what I do not understand is why does the Trace show up in $(1)$, $(2)$   Any help is appreciated.  EDIT  Let's write out the spinor indices explicitly for $(1)$  $$A_l = \Big(\sum_{s_1} u_{s_1 \color{red}{\delta}}(\vec p_2') \bar u_{s_1 \color{blue}{\alpha}}(\vec p_2')\Big) \gamma_{\color{blue}{\alpha}\color{green}{\nu}}\Big(\sum_{s_2}v_{s_2 \color{green}{\nu}}(\vec p_1') \bar v_{s_2 \color{gray}{\beta}}(\vec p_1')\Big)\gamma_{\color{gray}{\beta}\color{red}{\delta}} \ \ \ \ (3)$$  We know the following properties  $$\Lambda^+_{\color{red}{\delta}\color{blue}{\alpha}}(\vec p_2')= \sum_{s_1} u_{s_1 \color{red}{\delta}}(\vec p_2') \bar u_{s_1 \color{blue}{\alpha}}(\vec p_2')=\Big(\frac{\not{\!p_2'}+m_l}{2m_l}\Big)_{\color{red}{\delta}\color{blue}{\alpha}} $$  $$\Lambda^-_{\color{green}{\nu}\color{gray}{\beta}}(\vec p_1')= -\sum_{s_2}v_{s_2 \color{green}{\nu}}(\vec p_1') \bar v_{s_2 \color{gray}{\beta}}(\vec p_1')=-\Big(\frac{\not{\!p_1'}-m_l}{2m_l}\Big)_{\color{green}{\nu}\color{gray}{\beta}}$$  Thus we get  $$A_l = \Lambda^+_{\color{red}{\delta}\color{blue}{\alpha}}(\vec p_2')\gamma_{\color{blue}{\alpha}\color{green}{\nu}}\Lambda^-_{\color{green}{\nu}\color{gray}{\beta}}(\vec p_1')\gamma_{\color{gray}{\beta}\color{red}{\delta}}=-\operatorname{Tr}\Big[\frac{\not{\!p_2'}+m_l}{2m_l}\gamma_{\alpha}\frac{\not{\!p_1'}-m_l}{2m_l}\gamma_{\beta}\Big]$$  Now I have two questions:  1) Why are we allowed to manipulate $\sum_{s_1} \sum_{s_2} \Big[ \bar u_{s_2} (\vec p_2') \gamma_{\alpha} v_{s_1} (\vec p_1'))(\bar v_{s_1}(\vec p_1')\gamma_{\beta} u_{s_2} (\vec p_2'))\Big]_{(l)}$ in such a way to get $(3)$? What I mean is that I do not see what mathematical properties allow us to do so.  2) I get a negative sign. I guess it gets cancelled out due to an antysymmetric swap of certein indices, but what pair specifically?  Thank you :)


I'm looking for a brand of cookies from my childhood. On which Stack Exchange site should I ask?

I am trying to find an appropriate Stack Exchange site to ask about food. I am particularly interested in the name of a local Swiss cheese. Which is the appropriate site to ask similar questions?


I have a 2D binary array (size 1445 by 120), which I have clustered into 10 clusters using Python's  method. Each of the 1445 samples is given a cluster index of a number from 0-9.  My question is this: Is there a way to visualize these clusters in a 2D space, so that it looks something like this?: . I'm having trouble thinking of a way to map 2D binary data into coordinates. The data is very sparse and only ~5% are 1s, the rest are 0s. Any thoughts?

I have 100 data points, observed on 15 variables. I want to cluster my 100 observations, but I am unable to visualise 15-dimensional clusters in MATLAB.


How do I find the area shaded in red? The difficulty is actually in finding the area in blue.

Don't let the simplicity of this diagram fool you. I have been wondering about this for quite some time, but I can't think of an easy/smart way of finding it.  Any ideas?    For reference, the Area is:  $$\bbox[10pt, border:2pt solid grey]{90−18.75\pi−25\cdot \arctan\left(\frac 12\right)}$$


I'm using Ubuntu Xenial and mysql 5. editing the mysql.conf file didn't help. it's still showing active.

Currently, my MySQL server starts on every server boot. For a couple reasons, this is undesirable behavior. Is there a way to disable this behavior?


My final outcome will be a flat plane with a displaced board game piece that I can move around. I started by making a cylinder come out of the plane.  Then I wanted to use RGB curves to shape a board game piece. I tried for a while to turn this all into a vector I could use, but I just don't know how.  I'm using this less than and clamped add to make the plane under the cylinder full white so it doesn't change with the base of the game piece P.S. I've tried putting my final b&w texture into the x and y sockets on a Combine XYZ node, and I've tried doing that but multiplying the combine to the vector I'm working from, every solution I've conceived always makes a cone shape, despite the RGB curve shape. I had some weird problems like this on another project where the outcome is pretty much not related at all to the nodes

I'm struggle with vector displacement shader. I'm trying to do something like reverse cone but I can't figure out how to add radial direction. I would like to use RGB curves like screw (lathe) modifier but in shader. My actual setup:


I needed to tidy the files I am using in my blender project. After doing so blender doesnt know how to find the files as the path they were on has changed.   What can I do with blender to make sure it doesn't lose the paths when I tidy the files?

I'm moving all files to a new computer, via an external hard drive. I am certain that broken links will be a concern. What can I do to fix this? Is there a 'Best Practices' kind of way to prevent this problem beforehand? I have many hundreds of .blend files, and of course, I fear losing them.


If $f:X\to Y$ takes Cauchy sequence to Cauchy sequence then prove that $f$  is a continuous function.  Let $x_n$ be a  sequence in $X$ such that $x_n\to x\implies x_n$ is Cauchy $\implies f(x_n)$ is Cauchy but that does not guarantee that $f(x_n) \to f(x)$ .  So how is the above result true. Please help.

Let $(X,d)$ and $(Y,\rho)$ be metric spaces and $f:X\to Y$ be a function and suppose for any Cauchy sequence $(a_n)$ in $X$, $(f(a_n))$ is a Cauchy sequence in $Y$.  Is $f$ continuous?  Let $f$ be continuous, is it uniformly continuous?


I wrote a command to create a folder named with day's date and copy some file and folders to it.  @echo off for /f "tokens=1,2,3,4 delims=/ " %%a in ("%date%") do set wday=%%a&set month=%%b&set day=%%c&set year=%%d set tmpname="%day%_%month%_%year%" mkdir %tmpname%  xcopy /e \\192.168.0.11\bkup x:%tmpname%   Now, I want a command line that will delete folders that are 10 days old. How can I do this?

I'm looking for a function in batch that recursive delets all files/folders older than X Days from a given path.  Is there a Fast and easy snippet that could be placed in a batch function?


I've been trying to create a matrix (displayed in the image below), and I haven't been able to figure out so far.  I've tried the following code (as an example), but its not quite the same as you can see in the image. Can someone please guide me about this? \documentclass{article} \usepackage[utf8]{inputenc} \usepackage{blkarray}  \begin{document}   \[ \begin{blockarray}{ccccc} a & b & c & d & e \\ \begin{block}{(ccccc)}   1 & 1 & 1 & 1 & 1   \\   0 & 1 & 0 & 0 & 1   \\   0 & 0 & 1 & 0 & 1   \\   0 & 0 & 0 & 1 & 1   \\   0 & 0 & 0 & 0 & 1   \\ \end{block} \end{blockarray}  \]  \end{document}

I have the following code:  \documentclass{article} \begin{document} $ M = \bordermatrix{~ & x & y \cr               A & 1 & 0 \cr               B & 0 & 1 \cr} $ \end{document}   But this code makes a matrix with () and i would like it to be with [] How do i do this?


I'm trying to order by WeekId, then Order in my SQL table (end result should have workouts together by id, then ordered by the order specified), yet it is giving the wrong order. Is there something wrong with my LINQ statement?  private List<Workout> GetWorkouts(int id) {     return new OPPDBContext().Workouts         .Where(p=>p.ClientId == id).OrderBy(p => p.Order).OrderBy(p => p.WeekId).ToList(); }   The table:    The results:    Expected results:   Lat Pulldowns  Squats  Lat Pulldowns  Squats  Reverse Lunges

I have two tables, movies and categories, and I get an ordered list by categoryID first and then by Name.  The movie table has three columns ID, Name and CategoryID. The category table has two columns ID and Name.  I tried something like the following, but it didn't work.  var movies = _db.Movies.OrderBy( m => { m.CategoryID, m.Name })


doesn't seem to be necessary because Meta SE doesn't have its own Meta.  According to , the privilege to post a comment is set at 5 reputation. It seems to be far lower than other sites which require 50 reputation points and  is set at 100 reputaiton. Are they intentional?

What I am asking here is to please remove the privilege to participate in Meta for MSE.  This privilege is literally useless. You can't really have a meta site for a meta site. There's no Meta.Meta.SE here or any other SE site out there: Meta.SE covers for every site in SE, including itself.     When users find out that you don't really get anything new, it's kinda sad for those people. There is no use for it except just to be there and fill up the space between the first and third privilege. Privileges should be shown only if you earn something new, and this privilege to participate in the meta isn't new because it's where you report problems in all of SE, including Meta.SE.    So please remove the privilege to participate in meta just for Meta.SE.    This is not a dupe as this is a feature-request to remove it, not support on why it is there.


When I define a caption in lstlisting, LaTeX writes, for example, "Listing 1.1: ..." but I want to change the "Listing" to another language. How can I do this?

I am using babel package for Turkish language and I also use listings package. A code sample for one of my listings is as follows:  \begin{lstlisting}[label=some-code,caption=Poo Class] public class Person {      public int ID { get; set; }     public string Name { get; set; }     public string Surname { get; set; }  } \end{lstlisting}   As header, what I am getting is this:     Listing 7.1: Poo Class   I would like it to be like this:     Kod Örneği 7.1: Poo Class   Am I asking too much?


Doing a question on codility and was Asked to take two numbers and get the product. Then get the binary repesentation of that number and count the number of one's that are in the binary number.  My code is      return method(int a, int b)     {     int count=0;     int num;     num = a* b;     while(num>0)     {        if(num %2 ==1)        {            count++;        }      num = num >> 1;     }   return count;   }   Yet it only gives 50% correctness. Can anyone explain this. Is there something i missed that i should be aware off.

8 bits representing the number 7 look like this:  00000111   Three bits are set.     What are algorithms to determine the number of set bits in a 32-bit integer?


In this folder, there are 14GB of archives with names such as WiFiDiagnostics follow by a date. Is it safe to delete these archives? A reboot did not remove them.

Seems like there are around 5,000 wifi logs, each 2MB each, totaling nearly 10GB on my disk in /private/tmp. Can I delete these logs, or will macOS automatically delete them itself? I tried making a file using the mkfile command until I had about 2GB of disk space left, but nothing was automatically cleared.


Prove that each natural number has a multiple solely consisting of digits $0,1$ I have really no idea for this!!

I recently solved a , which says that,     A positive integer can be multiplied with another integer resulting in   a positive integer that is composed only of one and zero as digits.   How can I prove that this is true(currently I assume that it is). Also, is it possible to establish an upper bound on the length(number of digits) of the number generated?


I have the following minimal example:   \documentclass[12pt,a4paper]{article}  \usepackage{pgfplots}  \begin{document}  \begin{figure}   \begin{tikzpicture}     \selectcolormodel{gray}     \begin{axis}[       ybar,       xtick=data,       symbolic x coords={A},     ]       \addplot coordinates {(A,   1.000)};       \addplot coordinates {(A,   1.150)};       \addplot coordinates {(A,   1.393)};       \addplot coordinates {(A,   1.234)};       \addplot coordinates {(A,   1.599)}; % this will be purple       \addplot coordinates {(A,   0.912)};     \end{axis}   \end{tikzpicture} \end{figure}  \end{document}   which generates the following bar chart:    I would very much expect the last bar to also be grayscale. Subsequent bars are still grayscale.  Am I going crazy or doing something wrong?  I know that I can still just add [style={fill=black!40white}] to \addplot to manually overwrite the color, but why doesn't it do it automatically?

\selectcolormodel{gray} doesn't work for the duck hair, but it works for the other parts of the ducks, why?  \documentclass{ltugboat}  \usepackage{microtype}  \usepackage{graphicx}  \usepackage{ifthen} \newboolean{grayscale}    \setboolean{grayscale}{true}% for the black & white version    %\setboolean{grayscale}{false}% for the colored version     \usepackage{tikzducks} \usetikzlibrary{positioning}  \newenvironment{mytikz}{%     \begin{tikzpicture}     \ifthenelse{\boolean{grayscale}}{\selectcolormodel{gray}}{}      }     {\end{tikzpicture}}  \usepackage{ifpdf}  \ifpdf  \usepackage[breaklinks,hidelinks]{hyperref}  \else \usepackage{url} \fi   \begin{document}      Why \textbackslash\texttt{selectcolormodel\string{gray\string}} does not work for the duck hair?      Black and white version:          \begin{mytikz}         \begin{scope}[xscale=-1]             \duck[longhair=pink]         \end{scope}         \begin{scope}[xshift=10pt]             \duck[crazyhair=orange]         \end{scope}     \end{mytikz}      Colored version:     \setboolean{grayscale}{false}      \begin{mytikz}         \begin{scope}[xscale=-1]             \duck[longhair=pink]         \end{scope}         \begin{scope}[xshift=10pt]             \duck[crazyhair=orange]         \end{scope}     \end{mytikz} \end{document}


What is the best way to pass a boolean  into wp_localize_script as from what I can see everything is interpretted as strings.  I have a backend user options form for a plugin, when the values are returned I am using them for a jQuery script, one of them is a boolean, the user selects true or false from a dropdown, using wp_localize_script outputs these as strings (not booleans) "true" or "false" which will fail that parameter in the script.   <?php    $options = get_option('ng_slicknavmenu');   // Add PHP plugin variables to the $params[] array to pass to jQuery   $data = array (     'ng_slicknav_menu'         => $options['ng_slicknav_menu'],     'ng_slicknav_parent_links' => $options['ng_slicknav_parent_links'], // this is a boolean true/false     'ng_slicknav_speed'        => $options['ng_slicknav_speed'] ,   );    // Pass PHP variables to jQuery script   wp_localize_script( 'slickinit', 'phpVars', $data );   This is how I am doing it at the moment in my js init file     if( phpVars.ng_slicknav_parent_links === "true" )         $links = true;     else         $links = false;   jQuery(document).ready(function($){  ng_slicknav_speedInt = parseInt(phpVars.ng_slicknav_speed, 10);  jQuery(document).ready(function($) {             $(phpVars.ng_slicknav_menu).slicknav({                 allowParentLinks: $links,                 duration:ng_slicknav_speedInt,             });             });  });   But is there a better way?  I have tried some solutions from  ...  'ng_slicknav_parent_links' => ($options['ng_slicknav_parent_links']) ? true : false,   and  'ng_slicknav_parent_links' => (bool)$options['ng_slicknav_parent_links'],   But the answer does not work. The answers there for both result in a string of "1" for both values which is incorrect.

I am using wp_localize_script to pass a couple of values from my theme options to a javascript file. First I got the values from my theme options:  $options = get_option('theme');   $flex_auto = $options["slide-auto"]; $flex_animation = $options["slide-animation"]; $flex_direction = $options["slide-direction"];   Then I used wp_localize_script to create my array of values.  wp_enqueue_script('flexslider'); wp_localize_script('flexslider', 'flex_vars', array(     'flex_auto' => $flex_auto,     'flex_animation' => $flex_animation,         'flex_direction' => $flex_direction     ) );   In my javascript file I did this:   var $anim = flex_vars.flex_animation; var $auto = flex_vars.flex_auto; var $dire = flex_vars.flex_direction;  jQuery('.flexslider').flexslider({     animation: $anim,     slideshow: $auto,     controlNav: 'thumbnails',     directionNav: $dire,      slideshowSpeed: 7000,     animationSpeed: 1000,     touch: true, });   My theme options include some values that are made with checkboxes which work with 0/1 booleans while the jQuery plugin I'm using works with true/false. I tried saving the boolean value as strings by using a drop-down menu with two options, either true or false, but that doesn't seem to work. How can I pass the boolean values from the theme options to the javascript file? Any suggestions and hints very welcome :)


It would be very nice to be able to include images from an iOS device in a post (question, answer), etc.  I am testing the iOS app now and I had like to include some images, but it doesn't seem possible to do it now and since iOS is very willing to expose the images to the web I can't add it to imgur for example.

So this is pretty obvious. Image upload?    How about allowing to attach images in questions from the photo gallery, by perhaps sending the image for off-site storage like done from the full-web version?


I need to remove the repeated values from the list lista and put them in another list or in the same.  Distinct() doesn't work. listasemrepetidos returns the same as lista.  List<XYZr> lista = new List<XYZr>(); List<XYZr> listasemrepetidos = new List<XYZr>();    lista.Add(new XYZr(Convert.ToDouble(data[1].Replace('.', ',')), Convert.ToDouble(data[2].Replace('.', ',')), Convert.ToDouble(data[3].Replace('.', ',')), CLR));   listasemrepetidos = lista.Distinct().ToList<XYZr>();

I am playing with LINQ to learn about it, but I can't figure out how to use Distinct when I do not have a simple list (a simple list of integers is pretty easy to do, this is not the question). What I if want to use  on a list of an Object on one or more properties of the object?  Example: If an object is Person, with Property Id. How can I get all Person and use Distinct on them with the property Id of the object?  Person1: Id=1, Name="Test1" Person2: Id=1, Name="Test1" Person3: Id=2, Name="Test2"   How can I get just Person1 and Person3? Is that possible?  If it's not possible with LINQ, what would be the best way to have a list of Person depending on some of its properties in .NET 3.5?


$$\sum_{k=0}^{\infty} \frac{(-1)^k(2k+1)}{(2k+1)^2 + 1} = \frac{\pi}{4}\mathrm{sech}(\frac{\pi}{2})$$ I tried to consider breaking up the alternating factor of the series by decomposing it into 2 separate series - one adding the even terms and the other subtracting the odd terms, but then I couldn’t figure out where to go. My attempt, letting $S$ be the sum of interest. $$S = \sum_{k=0}^{\infty} \frac{(2(2k)+1)}{(2(2k)+1)^2 + 1} -   \frac{(2(2k+1)+1)}{(2(2k+1)+1)^2 + 1}$$ Don’t know what else to do.

Solve $$\int \limits_{0}^{\infty} \frac{\cos(x)}{\cosh(x)} dx$$ without complex integration.  This integral can be very easily solved with contour integration, but how can you solve it without taking a tour in the complex plane?


Sometimes it is appropriate to delete your own answer or question. That is often because someone explained a problem, and one accepts that the question or answer is not valuable. That is not directly related to down voting - an answer may be well liked, but not actually applicable.  When I agree to delete it based on the comment, I would typically like to reply to the comment - just before deleting the post. This comment I write is associated with that deleted post, and becomes unavailable with it. But that does not mean it is immediately completely lost.   I write that comment not to have it permanently associated with the question or answer, but to reply to the comment that convinced me to delete the post. It is typically to roughly explain my reasoning - or just thanking for the hint by explaining that I learned something from it.  All that is relevant to me is that the recipient (indicated by @) can somehow read the comment - even if it does not become permanent. It could appear in the inbox - and would be visible in part there - truncated to fit the space. Does the notification stay in the inbox even if the associated post is deleted? Can it still be read in full?

I have an inbox item but it looks like the person who answered the question and made response comment deleted his answer. Is there a way to see his/her id? I can see only part of the text in my inbox. Can I see it completely? I wanted to let the poster know that his answer was working! Not sure why he deleted it. Here's what I see in my inbox:  comment on Delete consecutives values in ArrayList of Int "Give it a try... That's called twice because I'm already at the beginning of the next ran..." on


I have a doubt about the following sentence.   "Vaccinating children has become increasingly popular these days."  According to my understanding children is plural so, this sentence suppose to be like this   Vaccinating children have become increasingly popular these days.  is this correct?  Thanks

Making adult decisions are/is really not fun.     What is the proper answer and why? My gut says "is" but I can't explain why.


okay, here is the thing -  I want to set up a Media + File server for my home...  I have a tp-link wifi router+modem.  I plan to use xbmc as the media server...i tried it out and i can now use it..  but, i have problems in the following -   how to use the same server as a file server?  i installed vsftpd but i cant understand how to use it from a remote ubuntu , android and windows machine...  is there any other software like xbmc for file server access apart from filezilla... filezilla is fine but i would like to know if there is anything as simple to use as a file manager to access the files on the server...i do use the ubuntu filemanager to access ftp server set up on my phone to access the phone but i cant seem to figure out how to use such a thing where i can just access a location in my network on ubuntu, android, windows pcs...  also, i cant figure out how to remotely upload files on the server for use through xbmc(like movies etc...i guess that shall also be done with ftp..but just asking if there is any other way)..  Access from outside the wifi network is not a priority at first though it would be a thing to add later for sure( guess it needs port forwarding on the router... :/ )  hope my question is understandable... thankyou...

I have the following pieces of hardware I would like to network mostly for file sharing (media primarily): 1 gaming laptop, 1 i7 (2.3Tb storage) desktop, 1 P4 desktop (500g storage), and 1 250gig PS3.  I am looking to setup a linux host (with a PS3 media server) with the i7 desktop but am concerned about leaving it on all the time. What stripped down, low energy usage distro can I couple with which windows & PS3 friendly software?  Also, how should i reformat my i7 (in terms of partitions, RAID options, whatever)? It has 2 1Tb drives (likely adding a third), and 1 320 gig.


I am trying to understand these of monitor in C# and tried out the following program.  Basically, this is all it tries to do:   Thread 1 acquires lock on an object (done in method m) Thread 2 invokes another method which changes the state of locked object when the lock is still held by Thread 1. (Main thread does this by calling anotherMethod)   Ideally, one would expect that when a lock is held on an object, no other thread can alter its state during the lifetime of the lock. But that doesn't seem to be happening.   class Program {     private int x = 0;      void Method()     {         lock (this)         {             Thread.Sleep(5000);         }     }      void AnotherMethod()     {         x++;         Console.WriteLine("entered");     }      static void Main(string[] args)     {         Program p = new Program();         Thread t = new Thread(() => p.Method());         t.Start();         p.AnotherMethod();     } }   What good is a lock if it doesn't freeze the state of object when it is in force?  Also, please help me understand this : if the sole purpose of lock statement is to mark some code as critical section, whats the significance of acquiring lock against an object?

The  says that public class SomeObject {   public void SomeOperation()   {     lock(this)     {       //Access instance variables     }   } }  is "a problem if the instance can be accessed publicly". I'm wondering why? Is it because the lock will be held longer than necessary? Or is there some more insidious reason?


Is there a name for (or even the NEED for a name for) taking the starting point (seeding) of Fibonacci's sequence "back" past $0$ or $1$ ?. $$ \left\{\vphantom{A^{A^{A}}}\ldots -21, 13,-8, 5, -3, 2, -1, 1, 0, 1, 1, 2, 3, 5, 8, 13, 21\ldots\right\} $$ I figure it could also be rewritten, reversing its order, with subtraction being action as $$ \left\{\vphantom{A^{A^{A}}}\ldots 21, 13, 8, 5, 3, 2, 1, 1, 0, 1, -1, 2, -3, 5, -8, 13, 21\ldots\right\} $$ It seems like someone a lot smarter than me would have already talked about this but it felt pretty good to walk in that person's same footsteps and have those personal "aha!" moments. Thanks for your time, Ben Prohm

I have a feeling this question is a duplicate, but it's not coming up in "Questions that may already have your answer."  We all know very well that $F(0) = 0$, $F(1) = 1$ and $F(n) = F(n - 2) + F(n - 1)$ for all $n > 1$.  I'm wondering about $n < 0$. My first thought was $F(-n) = -F(n)$, which is appealing from a multiplicative point of view, as it seems to preserve certain identities, like $F(n)^2 = F(n - 1) F(n + 1) - (-1)^n$.  But it doesn't quite make sense from an additive point of view, it doesn't seem to work both "forwards" and "backwards." For example, it would give us $F(-1) + F(0) = -1 \neq F(1)$.  How do we extend $F(n)$ to negative $n$ so as to maintain both the related identities and the basic defining identity?


A friend of mine ended up in a weird situation that they're looking for advice about: they published two different papers under identical titles. Google Scholar lists both papers with the same number of citations, and with the citations listed being the combined list for both papers.  What should they do? One solution might be to change slightly one the titles. They might do this by adding "a review" at the end of one of the papers, as it is a review paper. Are there better ideas?

For some reason I don't understand, Google Scholar thinks two of my papers are the same, despite different titles, co-authors, and publication years. When I click on one ("Resonant absorption as mode conversion?") it lists 27 versions, most of which are the completely different paper ("Three Dimensional MHD Wave Propagation and Conversion to Alfvén Waves near the Solar Surface. I"). It therefore combines the citations for the two. How can I split them? I even tried deleting both papers and adding them manually from scratch, but without success.


Is there a way to safely disable the Radeon Pro 560X dGPU on the 2018 15" MacBook Pro?  I know I can go the other way (force dGPU only) via the 'Automatic graphics switching' check box in Energy Saver but that is the opposite of what I want to do :)  I know on older models it was possible via magic nvram options.  Is it even possible on the 2018 MacBook Pro?   Edit: I should mention I have tried gfxCardStatus (and a more up-to-date port) however this does not block the dGPU from becoming active it simply switches back to the iGPU if something does fire up the dGPU. I want to fully disable the dGPU so it cannot be activated.

I'd like to disable the NVidia GTX 750M GPU on my MacBook Pro 15" (Retina, Mid 2014, Mac OS X 10.10 Yosemite). I know I can use GfxCardStatus but I read I could have a more permanent solution by changing some EFI flag. My question is:  How can I disable the discrete GPU from EFI? I assume this is persistent across multiple reboots. I'd also want to know how to undo it if needed.   Update: The question is basically whether the command mentioned in  is correct or not, and how to undo it if it doesn't work. . An answer to this alone is a correct answer, but it'll be awesome if you can also tell me:  If you force integrated graphics in GfxCardStatus, Mac OS X (up to Yosemite at least) doesn't allow you to use multiple monitors (even though the built in Iris Pro can do it). If I disable the discrete GPU from EFI, will macOS think that the integrated GPU is the one installed and will it let me use multiple monitors with it?  I heard that the same EFI setting is responsible for not even showing the integrated GPU to other operating systems than macOS and you have to trick it somehow to think it's macOS. Is that true? And if yes, how to do that?


If $\prod X_{\alpha}$ is normal then is $X_{\alpha}$ normal too? I would guess it's not? But I have no idea of how to prove it. Is there any proof to prove the claim or a counterexample otherwise?

It seems like this should be true, but I can't find the right argument.  Thanks.  Edit: How about   1) Take two disjoint closed sets in a partial product.  2) Extend them trivially to the entire product.  3) Separate them with disjoint open sets in the big product.  4) Restrict these open sets to the subproduct.  ???


If I change the input text of task1, the text box task2 is changed as expected.  But if I change the text box task2, text box task3 is not changed.  What is wrong with my code?  <!DOCTYPE html> <html lang="en">     <head>         <script type="text/javascript"  src="D:\Website\Jquery/jquery-2.1.4.js"></script>         <script type="text/javascript">             $(document).ready(function() {                 $("#tasks1").change(function () {                     alert('testingphase1');                     $("#tasks2").replaceWith('<input type="text" id="tasks2" placeholder="t2">');                 });                 $("#tasks2").change(function () {                     alert('testingphase2');                          $("#tasks3").replaceWith('<input type="text" id="tasks3" placeholder="t3">');                 });             });         </script>     </head>      <body>         <input type="text" id="tasks1" >         <input type="text" id="tasks2" placeholder="taks2">         <input type="text" id="tasks3" placeholder="taks3">     </body> </html>

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


I have sony xperia l running Android kitkat4.4.4 AKOP rom  I want to ask that my phones google play services draines my battery 60% to 80%  I tried all kind of fix but nothing sloved my problem  Thanks

I recently updated to the 10.1 M snapshot of CyanogenMod for my Sprint Galaxy S3 (d2spr). Ever since I did the update, I have been seeing crazy high battery usage from Google Services. I have tried just about everything I can think of to shut it off, but nothing seems to be working. I'm connected to Wi-Fi most of the day, so I don't think 3G has anything to do with it.  Attempted Troubleshooting:   Turn off Google Account Sync (per ) Turn off Google Now Turn off Location reporting   If possible, I'd like to fix this without using Juice Defender or any other battery management apps, but if that's what it takes, so be it.  So how can I get Google Services to stop sucking the life out of my phone?


I am sick of the new Windows 8. I just want to get rid of it completely and run Ubuntu.  I have a live CD. What do I need to do?

I would like to see a full how-to guide on how to install Ubuntu.


Why do water of water based liquids like sweat cool objects? The most clear example I have is the sweat on the skin. I learned that it absorbed heat because it evaporates, but this is something strange. I also read that by putting a little water on a can under the sun will cool the inside of the can, for the same reason as sweat. Why is this? Why does a liquid take away the heat, while it isn't even at the boiling point? The body is only 37 degrees Celcius, why does sweat "want" to evaporate already? I do know that liquids take energy to change its phase without adding to the temperature, but this is only at boiling point.

The title says it all. If I'm standing in the wind and I'm wet, I feel much colder than when I'm dry. This is true no matter how warm or cold the water. Why is this?


After installing ubuntu 16.10 in dualboot with ubuntu 14.04 (which is my prime os) i've suddenly encountered this kind of something:     Error mounting /dev/sdb1 at   /media/nerbellion/4d28c2ff-7649-4dd1-b423-3a48b5c695de: Command-line   `mount -t "ext4" -o "uhelper=udisks2,nodev,nosuid" "/dev/sdb1"   "/media/nerbellion/4d28c2ff-7649-4dd1-b423-3a48b5c695de"' exited with   non-zero exit status 32: mount: Bad message   /dev/sdb1 as /home     Error mounting /dev/sdb9 at   /media/nerbellion/a7a0a95e-8d8f-4486-8d8b-ae4f09aa11e2: Command-line   `mount -t "ext4" -o "uhelper=udisks2,nodev,nosuid" "/dev/sdb9"   "/media/nerbellion/a7a0a95e-8d8f-4486-8d8b-ae4f09aa11e2"' exited with   non-zero exit status 32: mount: Bad message   /dev/sdb9 as /root  What is the solution to this? It's happened after the installation.  By the way, /dev/sdb is my secondary external hdd, not the one, containing main os - 14.04.

I have a desktop computer with Ubuntu Desktop 14.04.4 LTS 64-bit with an attached HDD USB 3.0 4TB Intenso 1 partition ext4 data drive only (no OS or Apps). After a sudden power failure, I am unable to mount the drive (checked different host Linux machines with no result).  error message:  sudo mount /dev/sdd1 /mnt mount: wrong fs type, bad option, bad superblock on /dev/sdd1,        missing codepage or helper program, or other error        In some cases useful info is found in syslog - try        dmesg | tail  or so   Tried with fsck, e2fsck with no result. The error message says "Get a newer version of e2fsck".  Tried with all available superblocks backups with no result.  Tried offline file/drive Linux checkers on the offline and UNmounted volume with no result.  Finally, I received the following error message for which I couldn't find any help online:   "has unsupported feature(s): metadata_csum". e2fsck 1.42.9 (4-Feb-2014) /dev/sdd1 has unsupported feature(s): metadata_csum e2fsck: Get a newer version of e2fsck!   Can anyone help me take my data back?


Can I write  Our journey starts on the railway platform?  Or does it start at the platform?

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


I'm teaching myself how to build Wordpress plugins. I found a great guide to creating a Wordpress Meta Box and saving the form input from it.    I want to send the entered and saved form input from the Meta Box that is in the Post edit view of Wordpress to the Wordpress RSS in its own tag. So when the user publishes the Post the Meta Box form data saves and adds the saved input to the post Wordpress RSS nested in its own tag.  This is the code that saves the form input:  function prfx_meta_save( $post_id ) {  // Checks save status $is_autosave = wp_is_post_autosave( $post_id ); $is_revision = wp_is_post_revision( $post_id ); $is_valid_nonce = ( isset( $_POST[ 'prfx_nonce' ] ) && wp_verify_nonce( $_POST[ 'prfx_nonce' ], basename( __FILE__ ) ) ) ? 'true' : 'false';  // Exits script depending on save status if ( $is_autosave || $is_revision || !$is_valid_nonce ) {     return; }  // Checks for input and sanitizes/saves if needed if( isset( $_POST[ 'meta-text' ] ) ) {     update_post_meta( $post_id, 'meta-text', sanitize_text_field( $_POST[ 'meta-text' ] ) ); }  } add_action( 'save_post', 'prfx_meta_save' );

I'm trying to extend an RSS feed to output some post-meta from my website.  I have an 'event_date' meta-key and I need to order by this as opposed to the RSS standard publish date, which I know how to do if I could get that information.  I'm using the following code, which makes use of the Wordpress action hooks available in the RSS feeds. However, when I use these hooks, the feeds report that there are no items found, while without these the items are found, but of course I cannot order them as I need.  Am I doing something wrong in the way that I am outputting to the RSS feed?  /**  * Adds the 'event_date' meta value to a feed  */ add_action('atom_entry', 'add_event_date_to_feed'); add_action('rdf_item', 'add_event_date_to_feed'); add_action('rss_item', 'add_event_date_to_feed'); add_action('rss2_item', 'add_event_date_to_feed'); function add_event_date_to_feed(){      global $post;      $event_date_raw = get_post_meta($post->ID, 'event_date', true);     if($event_date_raw && $event_date_raw !== '') :         $date_object = DateTime::createFromFormat('D, d M Y H:i:s +0000', $event_date_raw);         $event_date = $date->format('U');     else :          $event_date = '';     endif;     printf("\t\t".'<eventDate>%1$s</eventDate>'."\n", $event_date);  }


I have a new laptop with only 4 GB of RAM. When I boot up the system, almost 2 GB are used for something.   Are there some quick tricks to increase available space? Maybe disable Superfetch as I have SSD, or decrease size of disk cache?

I thought that Windows 8 was supposed to be better with memory than Windows 7. So far, that is not my experience.  When I boot up my brand new laptop (Samsung NP550P5C-S03CA Intel Core i5 3210M 8GB 1TB ) , the Task Manager Performance tab tells me that I have:  8.0 Gb of DDR3 available  of this:  3.7GB is in use, leaving 4.2GB available  3.5/25.9 GB is committed and 1.4GB is cached.  162Mb paged pool, 2.4GB non-paged.  I then go to the Details tab, and I add up the Memory used by all the processes. It comes to about 300Mb. That is 0.3GB.  So what is using up the other 3.4GB of memory???  I then load up a bunch of programs that I use concurrently - notably Firefox (with about 30 tabs), Chrome, Thunderbird, Notepad++, Filezilla and my memory consumption goes up to 4.4GB. That seems about right.  I then work on it for a number of days, hibernating in-between, and I start to get notices that I am running low of memory. The performance tab says I am using 90% or more of my memory. The committed has gone up to 31GB. But if I add up the memory usage listed in the Details tab, it comes to only about 1800MB (I notice that Firefox has gone up to about 1300MB)  So, again, where has all my memory gone?  If I then close all the programs, it doesn't help. The details tab shows little running, yet the Performance tab shows I am still out of memory?  What is using up all my memory?  The only thing that clears it, is to do a restart. Which brings us back to the top of the loop, with the same initial question - what is using up over 4GB of my memory?  I never had these problems with windows 7.  As a sidenote, Win 8 also seems to be very unstable. Frequently getting programs not responding and crashing, including Windows Explorer, which seems to have to reload itself frequently.  Oh, and my wifi connection keeps dying and then I have to run the troubleshooter to get it all running again (my wife has that same problem on her brand new Acer).  So, what gives? How do I get my new laptop to work as fast as my 4 year old Sony Vaio with Win 7 and lower specs?  Anyone got any ideas? Or is this normal for windows 8?


Light (or any radiation as a matter of fact) is an electromagnetic wave so why doesn't it have a electric charge associated with it?  As far as I know only static or flowing electric chargers can produce electric fields and if it does have a charge why doesn't light (i.e. a photon) respond to an electric or magnetic field?

Since electromagnetic waves have both electric and magnetic field components, which oscillate in phase perpendicular to each other and perpendicular to the direction of energy propagation. How much is that electric charge? Can you possibly get a shock in some way?


As a child, my parents always made me finish my food even if I was already full. Food definitely isn't wasted this way, but overeating is not good either.  What would be the advantages and disadvantages of making/forcing a child to finish their food even if they are already full?   For the sake of this question, disregard the child's food preference (i.e. he doesn't not finish his food just because he doesn't like the food)

Like many young children, my 4.5 year old daughter will often stop eating her supper (6 PMish - she has breakfast and lunch at daycare) and say she's not hungry.  My instinctive initial response is to insist in some fashion because that's what my parents always did.  The assumption seems to be along the lines that they're just being picky or distracted, and will get hungry later, and that they need to learn to eat on a schedule.  But regardless of whether she'll be hungry 3 hours later, what if she really isn't hungry now - aren't I doing her a disservice in her development by ingraining the idea that she should keep eating when she's not hungry?  What should I do, just a gentle reminder that this will be her last meal of the night?


What can actually happen if CPU or GPU is over clocked?   Many people over clock their CPU so much it 'toasts'. What do they mean by toast. Does it really go up in flames or does it just stop working.  My Question  Back to my question what is the worst thing that can happen that could be considered dangerous.  Hope this makes sense

When you undervolt or overlock an CPU, when it passes a certain limit it starts to make the system unstable, reboot, etc. But these are the effects of it.  What I'm curious about is what happens on the CPU. What happens? It gives wrong answers to instructions? Bits on cache flip?


The solution should be within a page and please give full explanation.  The original question is,  What is $$\left(2018^{2019} + 2019^{2018}\right) \pmod{7} ?$$

I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two:   $13^{100} \bmod 7$ $7^{100} \bmod 13$   I've also heard of this formula:  $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$  But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?)  Any hints or pointers in the right direction would be great.


I had a custom Apex REST controller which was made available by a Site    But now I've added the Apex class into a managed package, I cannot access the REST controller anymore? How do I access the REST endpoint?

After my app is granted an OAuth token by the user, I take the "url" provided in the OAuth request, and the token, and make a request back to salesforce to store some settings.  In my unmanaged package testing the url looked something like this:    And this domain matched the domain in salesforce while the user was using the app.  Now that I uploaded a *Managed package though, it seems to be different. The URL in Salesforce looks like this    and the POST request to  is returning a 404   Is this expected? Do I need to append the app namespace to my API requests to the custom REST endpoint? Or is the namespace optional and can I just omit it when creating the managed package?


I install MySql Server and MySql Client on my Ubuntu 16.04.1 from "Ubuntu Software Center".  As far as I know, when you install mysql-server from terminal, it prompt for root password in the middle of installation process. But when I install it from "Ubuntu Software Center", it just installed and I don't know what the root password is.

I used apt install mysql-server to install MySQL on Ubuntu 16.04 but during the installation, it did not ask for root password.  After installation I got ERROR 1045 when I tried to login as root and mysql_secure_installation threw the same error. I purged and autoremoved then reinstalled but it does not work.  How could i fix this? Can I set the root password if I didn't set it during installation?  This is my installation log:   The following additional packages will be installed:   libaio1 mysql-client-5.7 mysql-client-core-5.7 mysql-server-5.7   mysql-server-core-5.7 Suggested packages:   mailx tinyca The following NEW packages will be installed:   libaio1 mysql-client-5.7 mysql-client-core-5.7 mysql-server mysql-server-5.7   mysql-server-core-5.7 0 upgraded, 6 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/17,9 MB of archives. After this operation, 160 MB of additional disk space will be used. Do you want to continue? [Y/n] y Preconfiguring packages ... Selecting previously unselected package libaio1:amd64. (Reading database ... 227144 files and directories currently installed.) Preparing to unpack .../libaio1_0.3.110-2_amd64.deb ... Unpacking libaio1:amd64 (0.3.110-2) ... Selecting previously unselected package mysql-client-core-5.7. Preparing to unpack .../mysql-client-core-5.7_5.7.12-0ubuntu1_amd64.deb ... Unpacking mysql-client-core-5.7 (5.7.12-0ubuntu1) ... Selecting previously unselected package mysql-client-5.7. Preparing to unpack .../mysql-client-5.7_5.7.12-0ubuntu1_amd64.deb ... Unpacking mysql-client-5.7 (5.7.12-0ubuntu1) ... Selecting previously unselected package mysql-server-core-5.7. Preparing to unpack .../mysql-server-core-5.7_5.7.12-0ubuntu1_amd64.deb ... Unpacking mysql-server-core-5.7 (5.7.12-0ubuntu1) ... Selecting previously unselected package mysql-server-5.7. Preparing to unpack .../mysql-server-5.7_5.7.12-0ubuntu1_amd64.deb ... Unpacking mysql-server-5.7 (5.7.12-0ubuntu1) ... Selecting previously unselected package mysql-server. Preparing to unpack .../mysql-server_5.7.12-0ubuntu1_all.deb ... Unpacking mysql-server (5.7.12-0ubuntu1) ... Processing triggers for libc-bin (2.23-0ubuntu3) ... Processing triggers for man-db (2.7.5-1) ... Processing triggers for systemd (229-4ubuntu4) ... Processing triggers for ureadahead (0.100.0-19) ... Setting up libaio1:amd64 (0.3.110-2) ... Setting up mysql-client-core-5.7 (5.7.12-0ubuntu1) ... Setting up mysql-client-5.7 (5.7.12-0ubuntu1) ... Setting up mysql-server-core-5.7 (5.7.12-0ubuntu1) ... Setting up mysql-server-5.7 (5.7.12-0ubuntu1) ... update-alternatives: using /etc/mysql/mysql.cnf to provide /etc/mysql/my.cnf (my.cnf) in auto mode Checking if update is needed. This installation of MySQL is already upgraded to 5.7.12, use --force if you still need to run mysql_upgrade Setting up mysql-server (5.7.12-0ubuntu1) ... Processing triggers for libc-bin (2.23-0ubuntu3) ...


Let $A$ be a ring with $0\neq1$ having $2^n-1$ invertible elements and at most $2^n-1$ non-invertible elements. Then $A$ must be a field? How many elements does the ring need to have? Because $2^n-1$ is odd, the characteristic of the ring is $2$. Thank you!

Let $A$ be a ring with $0 \neq 1 $, which has $2^n-1$ invertible elements and less non-invertible elements. Prove that $A$ is a field.


I've searched for this but no clear answers (especially on the latter). In what cases should you use a datetime or timestamp?

Would you recommend using a  or a  field, and why (using MySQL)?   I'm working with PHP on the server side.


I've been trying to install gcc-4.4 (needed for compiling old software I use) on a new system that is running Ubuntu 16.04.  The command uname -m gets an answer of aarch64 since the system has 64-bit ARM CPU cores.  I only have access through ssh (no graphical desktop), but I am able to run commands using sudo (such as sudo apt-get install gcc-4.4).  Unfortunately, even looking at answers to similar questions in this forum and spending several hours surfing the web for ideas, I cannot manage to install gcc-4.4.  I'm not a sys-admin or Linux expert, so please be gentle.  I want to learn.  Update:  Here's the error message:  ubuntu@ubuntu:~$ sudo apt-get install gcc-4.4 [sudo] password for ubuntu:  Reading package lists... Done Building dependency tree Reading state information... Done Package gcc-4.4 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'gcc-4.4' has no installation candidate ubuntu@ubuntu:~$

Is there a repository containing packages for old versions of gcc, for the latest Ubuntu. I want to install gcc3 alongside gcc 4, for programs that need gcc3 specifically.


I'm trying ti insert a tuple (record) on a sqlite db. it has one integer primary key. but when I try to insert I got an error "null object reference".  I searched a lot but unfortunately I can't resolved the error with respect to my case. Would you please give me hand?  here are the codes:  and the logcat says there is fatal exception.   this is how I created the the table. my sql insert function works correctly , but I think there is a problem with the datatype I have.  public class AccountHolder_to implements Parcelable {      private  Integer A_A_accountNumber;     private  String A_email;     private  String A_username;     private  String A_password;     private  String A_syncedURL;      private  Demographics_to A_A_patientID;      public AccountHolder_to () {         super();     }      private AccountHolder_to(Parcel in) {         super();         this.A_A_accountNumber= in.readInt();         this.A_email = in.readString();         this.A_username = in.readString();         this.A_password = in.readString();         this.A_syncedURL = in.readString();          this.A_A_patientID = in.readParcelable(Demographics_to.class.getClassLoader());      }      public int getA_A_accountNumber() {return A_A_accountNumber;}      public void setA_A_accountNumber(int id) {         this.A_A_accountNumber = id;     }      public String getA_email() {         return A_email;     }      public void setA_email(String email) {         this.A_email = email;     }      public String getA_username() {         return A_username;     }      public void setA_username(String un) {         this.A_username = un;     }      public String getA_password() {         return A_password;     }      public void setA_password(String pw) {         this.A_password = pw;     }      public String getA_syncedURL() {         return A_syncedURL;     }      public void setA_syncedURL(String sr) {         this.A_syncedURL = sr;     }      public Demographics_to getA_A_patientID() {         return A_A_patientID;     }     public void setA_A_patientID(Demographics_to pi) {        this.A_A_patientID = pi;    }      @Override     public String toString() {         return "accountHolder_Table [A_accountNumber:" + A_A_accountNumber + ", name:" + A_email                 + ",username:" + A_username + "password:" + A_password                 + "syncedurl:" +A_syncedURL +"patientid:" + A_A_patientID+ "]";     }      @Override     public int describeContents() {         return 0;     }     @Override     public void writeToParcel(Parcel parcel, int flags) {         parcel.writeInt(getA_A_accountNumber());         parcel.writeString(getA_email());         parcel.writeString(getA_username());         parcel.writeString(getA_password());         parcel.writeString(getA_syncedURL());          parcel.writeParcelable(getA_A_patientID(), flags);     }      public static final Parcelable.Creator<AccountHolder_to> CREATOR = new Parcelable.Creator<AccountHolder_to>() {         public AccountHolder_to createFromParcel(Parcel in) {             return new AccountHolder_to(in);         }          public AccountHolder_to[] newArray(int size) {             return new AccountHolder_to[size];         }     };      @Override     public int hashCode() {         final int prime = 31;         int result = 1;         result = prime * result + A_A_accountNumber;         return result;     }      @Override     public boolean equals(Object obj) {         if (this == obj)             return true;         if (obj == null)             return false;         if (getClass() != obj.getClass())             return false;         AccountHolder_to other = (AccountHolder_to) obj;         if (A_A_accountNumber != other.A_A_accountNumber)             return false;         return true;     } }   Thank you in advance !

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I am interested in studying computer science after I graduate, and I am aware that, based on your occupation, it can be a math heavy field. I've looking into discrete mathematics, and am interested in what the basis of it is. Also, if anyone has any experience, could you recommend any books for studying?

I am going to a Computer Science Course in University next year. I heard that Discrete Mathematics is whats required for Comp Sci so, I am looking for resources/books that I can read to get started with. I picked up . I find that some things are alittle hard to understand still. I have also looked at some videos from , I find the videos easy to understand. Except that I don't really know where am I supposed to start 1st. I am on algebra now, but can someone tell me whats the sequence I should go from here, eg. topics/playlists?  An you know, for maths, there must be alot of practice. So where can I find lots of practice questions? Schaum's Outline of Discrete Mathematics has quite little practice questions.


I want to make Ubuntu panel (made by "dash to panel" extension) transparent forever, Now it's transparent when desktop is active and solid when any kind of window is active, like on this picture(panel is bottom :P).

I'm using Ubuntu 17.10. I want the Panel to be always transparent instead of dynamic transparency.


3 sentences:-  A number of such incidents has/have been reported by the local residents so far. The number of such incidents is/are very low. The number of elephants in Kerala has/have been dwindling.  What is the correct form of verb in the sentences, and why?

Possible Duplicate:          From the grammatical view both are correct, but please explain the difference in meaning:   The number of students in the class is fifteen. A number of students were late for class.


If I use ls -l assets/**/*.webp  in bash, it works fine However, if I put it into a script, it will complain: ls: assets/**/*.webp: No such file or directory I noticed that if I remove the trailing .webp ls -l assets/**/*  this script works, but that's not what I want here's the full script which will fail #!/bin/bash ls -l assets/**/*.webp

I'd like to write something like this:  $ ls **.py   in order to get all .py filenames, recursively walking a directory hierarchy.  Even if there are .py files to find, the shell (bash) gives this output:  ls: cannot access **.py: No such file or directory   Any way to do what I want?  EDIT: I'd like to specify that I'm not interested in the specific case of ls, but the question is about the glob syntax.


Evaluate $$\int_{-a\pi}^{a\pi} \frac{\cos^5(x)+1}{e^x+1}dx, \quad a \in \mathbb{N}$$   In the beginning, I didn't have any ideas of how to solve this. The one that later came to mind was to try using Feynman's technique, but I couldn't think of the proper function to use for the second variable.   Any ideas?

Let $[-a, a] \subset \mathbb{R}$ be an interval. Let $f: [-a, a] \rightarrow \mathbb{R}$ be a Riemann-integrable function such that $f(x) = f(-x)$ for all $x \in [-a, a]$. Let $b \in \mathbb{R}_+$.  Question: Is there a "good" way to simplify the integral $\int_{-a}^a \frac{f(x) + 1}{b^x+1} \,\mathrm dx$?