Hi anyone knows how to evaluate this limit?  I let $P$ = the limit  Then $\log$ both sides to bring the $1/n$ power down.  After that I integrate it by parts and gotten until   $\log P = 2\log2 - 1$  But from here how to get rid of the $\log$ and get $P$?

Calculation of  $\displaystyle \lim_{n\to \infty}\prod_{r=1}^{n} \left(1+\frac{r}{n}\right)^{\frac{1}{n}}$  $\bf{My\; Solution::}$  Let $y=\displaystyle \lim_{n\to \infty}\prod_{r=1}^{n} \left(1+\frac{r}{n}\right)^{\frac{1}{n}}$, Now taking $\log_{e}$ on both side  $\displaystyle \log_{e}(y) = \lim_{n\to \infty}\log_{e}\left(\prod_{r=1}^{n} \left(1+\frac{r}{n}\right)^{\frac{1}{n}}\right)=\lim_{n\to \infty}\frac{1}{n}\cdot \sum_{r=1}^{n}\log\left(1+\frac{r}{n}\right)$  Now Using Reinman Sum of Integral ...  $\displaystyle \log_{e}(y) = \lim_{n\to\infty}\frac{1}{n}\cdot \sum_{r=1}^{n}\log\left(1+\frac{r}{n}\right) = \int_{0}^{1}\ln(1+x)dx = \log_{e}(4)-\log_{e}(e) = \log_{e}\left(\frac{4}{e}\right)$  So $\displaystyle y =\lim_{n\to \infty}\prod_{r=1}^{n} \left(1+\frac{r}{n}\right)^{\frac{1}{n}} =\frac{4}{e}$  But how can i solve above question using Stirling Approximation,  May I ask for help?  Thank you in advance!


Aloha Travelers! As a general rule, if you are going A-C via a country B, which requires a transit visa in advance, should I get another visa if my return also happen to be C->B->A ?  I am planning to visit a lesser known country, and the point B country requires a visa in advance. There is an embassy in our country and it's easier to get a visit visa. Is it the general practice to get 2 transit visas, or is there such "multiple-entry transit visa" thing?  One transit visa allows me to stay 5 days in the country, and provide the departure ticket. The point C country also has an embassy of country B there, and I will be saying 20 days in the country C.  Please note I'm asking the general rules, and not the specifics. That is not just for a singe trip. The point B is a hub for most flights so I'm looking for potential future trips and to know the general rules about this.  Update 1: the point B country is Malaysia.  Their rules are somewhat strange that they do have a transit visa on arrival, but that is only if the destination country is in a a few selected array of countries, which my third country is not in.   Update 2: I could ask an official representative at the KLIA2 airport the same question. Note that this is relevant only to citizens of countries that Malaysia is not offering visa on arrival or visa-free entry. Unfortunately, Sri Lanka is being one of them.  See the information on . If you are visiting any country listed under #2, you can pass the immigration control and visit the country. However, on your return flight, you cannot do this if your destination (home) country is not in the list.  After checking flight routes and times of Malaysia Airlines and AirAsiaX, it seems they work nicely with the rules as well. While I'm not 100% sure about this, all of the flights have 2-5 hours of time in between flights which practically makes you stay in the airport.

I am an Indian passport holder travelling from China to India via Kuala Lumpur, on Air Asia tickets bought separately. The layover is 4 hours and 30 minutes.  Do I need a transit visa?


Iam running Ubuntu Server 14.10 in Oracle VM VirtualBox. Whenever i start the VirtualBox, it changes IP address. To run putty or WinScp, i had to check everytime. Is there any way to assign a static IP so that i need not login to check IP everytime i start the VirtualBox

I have a public ip as below which is static (my isp provided) as below:  IP Address: x.x.146.50 Subnet Mask:    255.255.255.240 Default Gateway:    x.x.146.49 DNS1:   x.x.1.196 DNS2:   x.x.7.196   But what is my Network, Broadcast and DNS (this scared me for ages, looking for a easy way to do 100% accurate calculating/math).  iface eth0 inet static     address x.x.146.50     netmask 255.255.255.240     network ????????????     gateway x.x.146.49     broadcast ?????????   Follow up: (short cut)  $ ipcalculator 8.8.8.8/28 Address:   8.8.8.8              00001000.00001000.00001000.0000 1000 Netmask:   255.255.255.240 = 28 11111111.11111111.11111111.1111 0000 Wildcard:  0.0.0.15             00000000.00000000.00000000.0000 1111 => Network:   8.8.8.0/28           00001000.00001000.00001000.0000 0000 HostMin:   8.8.8.1              00001000.00001000.00001000.0000 0001 HostMax:   8.8.8.14             00001000.00001000.00001000.0000 1110 Broadcast: 8.8.8.15             00001000.00001000.00001000.0000 1111 Hosts/Net: 14                    Class A  1) It tells me Broadcast what to copy and paste 2) It tells me Netmask what to copy and paste 3) It tells me Network what to copy and paste   Now its Easy! i was always finding them complex in my head to do manual calculation and server is down for 20 days :P. Not not anymore.


how would you fix the hole so that its even like the other parts of the mesh?

Is it possible to fill this hole with a grid?    I tried with Grid Fill    With F fill (but no grid)


Can I use Moto G2 with Google Cardboard. I just want to experience Virtual reality in a cheapest way possible. I've a Moto G2, So I was wondering If I can use Moto G2 with Google Cardbaord. If anybody has used it then please suggest me, What kind of stuff I would be able to see and what I won't be able to.

Google cardboard comes with 3D glasses. Does that mean that we will be able to watch 3D videos using a smartphone like the Moto-G (1st edition) which is not 3D enabled?


Have below Selenium Program using Object Repository Library File but the same is failing and shows java.lang.NullPointerException. Have commented the specific syntax lines as "error". Also attached the error screenshot and config.property files.enter image description here. Have tried to identify the cause but could not. please clarify the cause of the failing and error message.   package objectrepository; import org.openqa.selenium.chrome.ChromeDriver; import org.openqa.selenium.WebDriver; import org.testng.annotations.Test; import objectrepository.Lib_ChromeDriver;  public class OBRClass_2 {  @Test public void launch_chrome() throws Exception{  Lib_ChromeDriver LCD = new Lib_ChromeDriver();// Lib_ChromeDriver is the Object Repository Library File   System.setProperty("webdriver.chrome.driver", LCD.Path());// error shown  WebDriver Snap = new ChromeDriver();  Snap.get(LCD.AppURL());   } }   and:  // a Java Class containing Constructor & method and is saved as Library file. // Constructor has will call the ObjectRepository File and  // method will call the Call the ChromeDriver Location to Launch the same // this Library Class can be called in Selenium program to launch the Chrome Driver   package objectrepository;  import java.io.File; import java.io.FileInputStream; import java.util.Properties; import org.testng.annotations.Test;  public class Lib_ChromeDriver {  Properties Prop;  @Test public void Lib_ChromeDriver() throws Exception{// Constructor calling the Object Repository File  File OB_File = new File("./Config/Config.property"); FileInputStream OB_FIS = new FileInputStream(OB_File); Prop = new Properties(); Prop.load(OB_FIS); }  public String Path() throws Exception{// method calling the ChromeDriver Path to Launch the same  String ChromePath = Prop.getProperty("ChromeDriver"); // error shown return ChromePath; }  public String AppURL() throws Exception{  String AppURL = Prop.getProperty("URL"); return AppURL; } }

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?


If $x,y,z \in \mathbb{R^+}$ such that $x+y+z=3$. Prove the inequality $\sqrt x+\sqrt y+\sqrt z\ge xy+yz+zx$.    My work: We have   $$3(x+y+z)=x^2+y^2+z^2+2(xy+yz+zx) \implies (xy+yz+zx)=\dfrac12(3x-x^2+3y-y^2+3z-z^2)$$  So, we have to prove, $\sqrt x+\sqrt y+\sqrt z-\dfrac12(3x-x^2+3y-y^2+3z-z^2)\ge 0$    Now, I cannot proceed further. Please help.

Let $a,b,c$ are non-negative numbers, such that $a+b+c = 3$.  Prove that $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge ab + bc + ca$    Here's my idea:  $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge ab + bc + ca$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(ab + bc + ca)$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) - 2(ab + bc + ca) \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) - ((a+b+c)^2 - (a^2 + b^2 + c^2) \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) - (a+b+c)^2 \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge (a+b+c)^2$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3^2 = 9$  And I'm stuck here.  I need to prove that:   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge (a+b+c)^2$ or  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3(a+b+c)$, because $a+b+c = 3$  In the first case using Cauchy-Schwarz Inequality I prove that:  $(a^2 + b^2 + c^2)(1+1+1) \ge (a+b+c)^2$  $3(a^2 + b^2 + c^2) \ge (a+b+c)^2$  Now I need to prove that:   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3(a^2 + b^2 + c^2)$   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a^2 + b^2 + c^2)$   $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge a^2 + b^2 + c^2$   I need I don't know how to continue.  In the second case I tried proving:  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a+b+c)$ and  $a^2 + b^2 + c^2 \ge a+b+c$  Using Cauchy-Schwarz Inequality I proved:  $(a^2 + b^2 + c^2)(1+1+1) \ge (a+b+c)^2$  $(a^2 + b^2 + c^2)(a+b+c) \ge (a+b+c)^2$  $a^2 + b^2 + c^2 \ge a+b+c$  But I can't find a way to prove that $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a+b+c)$  So please help me with this problem.  P.S   My initial idea, which is proving:  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3^2 = 9$  maybe isn't the right way to prove this inequality.


I want to start a list of the programming-related StackExchange websites, since there are more and more SE sites that might have a more focused community, rather than SO.  If you have more than 100 rep feel free to edit the first answer itself. Otherwise post a link seperately and someone will add it in :). I'm not doing this for rep so please don't close this question.  Lists

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


I am trying to compile a latex file but I noticed that the file ``freezes" at the point of this array:   \[\left(\begin{array}{ccc} a_{11} & a_{12} & a_{13}\\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{23} & a_{33} \end{array}\right) \left(\begin{array}{c} u_{t}^{\tau} \\ u_{t}^{g} \\ u_{t}^{y} \end{array}\right) = \left(\begin{array}{ccc} b_{11} & b_{12} & b_{13}\\ b_{21} & b_{22} & b_{23} \\ b_{31} & b_{23} & b_{33} \end{array}\right) \left(\begin{array}{c} e_{t}^{\tau} \\ e_{t}^{g} \\ e_{t}^{y} \end{array}\right) \]   That array was a copy and paste from another latex file. Is there a particular package that creates this problem ? Once I remove the array from the file it compiles with no problems.  The document class that I use is {book} with the following sample of packages:   \usepackage[a4paper, total={6in, 9.5in}]{geometry} \usepackage{amsmath, mathtools} \usepackage{amssymb} \usepackage{multirow} \usepackage[flushleft]{threeparttable}

I'm trying to compile my LaTeX file (an article), but I keep getting a Windows API error: my synctex file is busy - the filename has been changed and appended with (busy).  I'm using TexMaker to compile the file, but it occurs in TeXStudio as well.  When I create a new file I can compile it once before this issue occurs.  The API error is     pdflatex: Windows API error 4350:  This file is currently not available for use on this computer. pdflatex: Data: Report4.synctex.gz


This question is in relation to the following YouTube video:    In it, an electrical generator is shown consisting of a CPU fan with thin magnets attached to the fan blades. Allegedly, bringing another magnet close to the fan causes the fan to spin. The fan's motor is utilized as a generator to power a light-bulb.  Just to be clear, I know there's no such thing as "free energy". But I'm puzzled as to why the CPU fan rotates at all. It seems intuitively that the most you could accomplish by approaching another magnet to the fan is to set up an oscillating motion (rather than continuous rotation).  Several ways of "cheating" come to mind: A magnetic stirrer hidden under the table? But, in part of the video, the demonstrator holds the fan somewhat above the table. A small battery hidden somewhere on the fan? We don't get to see it from all sides, but it doesn't look like he's flipping a switch.  Some of the comments on the video speculate that the energy comes from demagnetizing the magnets, but this seems dubious. If the device "works" to any extent it seems the input energy would be in the form of work performed by the person moving the magnet. But can the fan be started spinning by motion of the magnet alone?

There are many videos on youtube in which people arranged magnets in circle and rotated one placing in middle of that circle on a shaft, and the magnet (magnet motor) starts madly and continues its movement. Do they really rotate infinitely? If so, do they from where they get that extra energy to move so fast and infinitely?    EDIT: This question is about real world scenario  UPDATE: I am unable to find that particular video about which i talked about -- I added them to my favourites, but they are all now deleted :( -- there are hundreds of that that kind of videos. Some example videos links


I am attempting to write several parts of code that work together to show Classic formatted list views (with pages to click through) in Lightning and am barely knowledgable in HTML, CSS and sort of understand Apex. I've been instructed that I need: 1) Apex Class 2) Apex Test Class 3) Apex Controller 4) Apex Test Controller 5) Visualforce Page -and- 6) Component.  I've been able to get basic outlines for all except the Apex Test Class, and no matter what I try, I keep receiving error "Add test methods to your test class."  Can someone please help fix this test class?   Thank you, Kristen  Apex Class: NitishContactListViewClass  public class NitishContactListViewClass { public List<SelectOption> listViewNames{get; set;} public String conFilterName{get; set;}  public NitishContactListViewClass(ApexPages.StandardController controller){     String q = 'SELECT Name FROM Contact LIMIT 1'; //Any object whose list view you are trying to retrieve.     ApexPages.StandardSetController ACC = new ApexPages.StandardSetController(Database.getQueryLocator(q));     List<SelectOption> ListViews = ACC.getListViewOptions();     listViewNames = new List<SelectOption>();     for(SelectOption w : ListViews ){         listViewNames.add(new SelectOption(w.getLabel(), w.getLabel()));     } }  public PageReference resetFilter() //Dummy function {     return null; }  }   Apex Test Class: NitishContactListViewClass  @isTest     public class NitishContactListViewClassTest {  @isTest static void NitishContactListViewClass() {     listViewNames = new List<SelectOption>(00B60000005aJl1EAE)     System.assertEquals("My Contacts", listViewName );    }   }

This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, including more unit test resources, navigate to the  tag.  This canonical question is intended to address several classes of common questions by providing a quick summary and links to comprehensive resources:   How do I start writing my first unit test?  How do I unit test this code?  I need help writing this unit test.   Salesforce Stack Exchange looks for detailed, specific questions that the community can help you with, and can't write tests on your behalf. We feel that working with the resources below can help you get started, and we encourage you to make an attempt to write your test and return to SFSE with your specific questions when you encounter challenges you can't resolve.


Consider the following sentence:     The main culprit together with his associates was/were arrested.   Which should be used, was or were?

My question arises from , where OP asks whether he should use the singular or plural verb form after "the title, as well as the tone,"  As luck would have it, when I searched Google Books for , I found...        ...and...        At the risk of having this question closed as just peeving, I feel that the first one should have been plural "err", because without the commas it seems to me both "the title" and "the tone" have more or less equal status as "joint" subjects of the verb, making it plural.  On the other hand, I feel the commas in the second example effectively demote "the tone" to "parenthetical" status (the clause is almost incidental). Since this encourages us think of "the title" as the primary subject, it should have been singular "derives".  I'm no great fan of "grammatical rules", but it seems weird to me that the only two relevant examples for this specific wording should both (in opposite ways!) contradict my inclinations.  What's going on?


How to verify the continuity of the following function at $(0,0)$ :  \begin{cases}f(x,y)=\cfrac{x^3}{x^2+y^2}& \text{if } (x,y)\neq (0,0)\\ f(0,0)=0\end{cases}

How to show if the limit $$ \lim_{(x,y) \to (0,0)} \frac{x^3}{x^2 + y^2}$$ exists? I suspect that there is, as I can't find any path that would show that limit doesn't exist, and WolframAlpha also suggests that the limit is (0,0).  In general, can you recommend any tips how to learn to approach similar limit problems (fractions and polynomials like this)? edit That is, excluding the polar coordinate conversion method?


SMB stands for small to midsize business. If I was using 'SMB' on my resume, what would be more appropriate to use before 'SMB'.   in a SMB environment   or   in an SMB environment   How do I know how the reader will read it? Some read the letters out loud which would produce the "ess" sound which would require the "an" but someone else who knows what it stands for, (which I hope is everyone) will be expecting the preceding word to be "a".

99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people & references I respect disagree.  Which of the following would you precede with "a" or "an," and why?   FAQ FUBAR SCUBA   [Note: I've read the questions  and , but the rules given there don't necessarily apply here.]    [Edited to add]  Here's a shorter (and hopefully clearer) version of the question…  In written English, which is correct (and why): "a FAQ" or "an FAQ"?  Some references with differing opinions:   an: the  and  a: the Microsoft Manual of Style for Tech Publications, 3e either: the  and


When reading the topic about primary and rational canonical form of matrices I stuck myself on this theorem:     The matrices $A,B\in K^{n\times n}$ are similar if and only if their characteristic $\lambda$-matrices $(A-\lambda{I})$ and $(B-\lambda{I})$ are $\lambda$-equivalent; more precisely if $P(\lambda), Q(\lambda) \in K[\lambda]^{n\times n}$ are invertible such that $(B-\lambda{I})=Q(\lambda)(A-\lambda{I})P(\lambda)$ then $P(\lambda)=P$ and $Q(\lambda)=Q$ are constant matrices satisfying $Q=P^{-1}$ and $B=Q A P$.    (in Slovak).   The main point in the proof of this theorem seems to be the assertion: If $P(\lambda), Q(\lambda)$ are invertible and $(B-\lambda{I})=Q(\lambda)(A-\lambda{I})P(\lambda)$ then $P(\lambda)=P$ and $Q(\lambda)=Q$ are constant matrices.  What is the proof of this assertion?


I have this question and I don't know exactly how to solve it; the question is:  Give the number of shortest paths from (-2,5) to (2,-1)? please, I need a help...

How do you find the number of the shortest distances between two points on a grid where you can only move one unit up, down, left, or right? Is there a formula for this?  Eg. The shortest path between $(0,0)$ and $(1,1)$ can be $(0,0)\to (0,1)\to (1,1)$ or $(0,0)\to(1,0)\to(1,1)$, so there are two shortest paths.


I'm looking at deploying a server for high bit rate video streams up to 250 Mbps. There are 8 clients in the network which at any given point may be playing any given stream, so a worst case scenario is 8 x 250 Mbps or 2000 Mbps. How would I go about sizing the RAID array correctly, given that I would opt for a RAID5 array? Can I consider this as a strictly sequential I/O workload and would therefore basic calculations suffice? I.e. a RAID5 array of 8 disks with 150 MB/s throughput per disk would yield around 1200 MBps sequential throughput which would be theoretically sufficient. Thanks for your insights.

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


I have an apparently simple question, but quite surprising I can't find any answer online. The question is: is it possible to run PCA on proportions? Since I am not specifically trained in statistics or mathematics it would be great if someone could give a simple answer, besides giving an appreciable mathematical grounded answer. Thank you

I would like to analyze a small matrix N (8 cases) x M (6 variables) whose values are the number of responses each case get on the different variables. These values have a very different scale because each case had a very different exposure, thus the number of responses are cleary very different in size. My aim is to find the distinctive characteristics (the "profiles" we can say) of each case with regard to the variables, and comparing the analysis results with a theoretical typology.   My first approach was to calculate the proportion for each case in order to normalize the values in a comparable scale (after this step I ended up with a matrix N x M containing proportions, with each row that adds up to 1) and then apply a Principal Component Analysis (PCA) in order to discover the most characteristic relations that link the cases to the variables, also discovering the main factors underlying the variables, which I try to interpret with the aid of my theoretical typology.  I already discovered that proportions are not appropriate for PCA analysis, but there are also "robust" PCA to analyze "compositional data" (the proportions). However, I am not specifically trained in statistics, and I am sure that there is some better and more correct approach to use for this case.   You can find   Can someone help me? Thanks


Tigers are found both in Asia and in Africa.  Tigers are found both in Asia and Africa.    I could use in twice in this sentence. Can I omit it the second time?

Is on needed a second time in this sentence?        There is a bad effect either on human health or environment.    There is a bad effect either on human health or on environment.


I use this code to place an image next to a character while matching its size:  \documentclass{article}  \usepackage{mwe} \newlength{\Height} \newlength{\Depth} \DeclareRobustCommand{\ScaleImage}[1]{%     \def\temp{#1}\ifx\temp\empty         \PackageWarning{Eu}{Empty character given}%     \fi     \raisebox{-\depth}{%         \vphantom{#1}%         \settoheight{\Height}{#1}%         \settodepth{\Depth}{#1}%         \addtolength{\Height}{\Depth}%         \includegraphics[height=\Height]{example-image-a}% }}  \begin{document}     \dots \ScaleImage{!}!      \dots) \ScaleImage{)}      an \ScaleImage{a} anonymous \dots      \dots fooling around, \ScaleImage{,}      \ScaleImage{} \end{document}   This is how this looks:    It works pretty well, but note, for example, the example with the exclamation mark, which exceeds the size of the red box. Am I missing something, or is there some discrepancy between how a character is measured and how it is printed?

How can I take input text and replace each character with a solid (and/or hollow) rectangle representing the bounding box for that character? In the case where two characters are closer together from kerning (e.g. microtype) the boxes would overlap. The addition of the boxes should not change the spacing of the text - I'm looking for a "draft mode" for the letters.  Solutions and Problems  Both solutions presented by Yiannis Lazarides and egreg seem to do a reasonable job for single words, though as mentioned, it seems that kerning was not completely respected. Below are the results (without markup/egreg/Yiannis):    Both solutions fail however when multiple words are involved. One of the answers completely eats a space while the other overcompensates. Both of them seem to choke on a line break as well.


This is a simple question, but too generic to find on google, I guess.  How would I set-up a program to run every time I opened the terminal?   For example; every time I open the Terminal it runs hello.sh which would echo "hello bofimpact".  Do I need to put hello.sh in a boot folder for the terminal or something?  (p.s.: I'm using Ubuntu 14.04 )

I'm running Arch-Linux ARM on a Raspberry Pi.  My project goal is to have a barcode scanner attached to the Pi that forwards the scanned messages to a server in a LAN.  To harden the system against power outages etc. and minimize required user interaction, I wish to set it up so that a certain user is logged in automatically at startup (done and works) and a specific program is to be run at startup (done and works but not as intended).  I've done this so far by adding  exec mono scannerSoftware.exe 127.0.0.1 1234 randomString   to /home/certainUser/.bash_profile so it gets executed only once even when I'm switching back and forth to root (in contrast to bashrc).    The particular problem I am having: When I launch the system, it works as intended (login as certainUser, starting scannerSoftware.exe); BUT if I want to switch users and hit Ctrl+C, it restarts the login process, logging certainUser in again and running the program again => back to where I came from.  My guess as to why this happens is that the sys detects "login not complete, better start it again".  I could circumvent this by spamming Ctrl+C right around the login so that I practically interrupted it. Of course, this is not good practice. Suffice it to say it is not practical at all.  My question: How can I set it up so the program gets executed AFTER login is complete so that Ctrl+C'ing out brings me to a normal bash prompt as certainUser instead of beginning the endless login-cycle?  EDIT: I'm not using any graphical interface or such, only commandline (bash on tty), because when done the system won't even have a display.


Recently we merged contacts in Salesforce and deleted 4 million duplicate records from salesforce. Now we would like to delete the same records from SFMC.I know once we deleted those records , they would not have synced back to marketing cloud and our synchronized data extension in SFMC would automatically get rid of those merged records. But those customers would be in “All Contacts” which would count against our Contacts and we would like to delete them from All contacts. How should we go about it considering we have 72 million records in All Contacts?Also if I run left join on All Contacts and synchronized data extension,it times out.  Just to add,I am not just trying to identify the numbers of contacts but i have identified them and facing issue with the volume of data. Also I have deleted the customers from Salesforce and i use person account there. Does it make sense to compare All contacts with synchronized DE contacts_salesforce?I only want to filter those 4 million (which i had merged in CRM) from the All contacts.

I'm trying to delete a large number of records from SFMC to avoid being charged extra. I've run several different SQLs to help identify the records I don't need, but when I run the Contact Count report, it still shows approx 100K billable contacts and approx 60K distinct email addresses.  Here are the SQLs I've tried:   No Opens in past 5 days Leads/Contacts not in SFDC  SubscriberKey as Email Address Leads/Contacts where SubscriberKey is Empty Unspecified records (DE populated by MC Support)    These efforts reduced the count a good amount, but not as much as I was expecting.   Has anyone else gone through this process before and if so, what queries can you share that might help my case?


If I had a cube like object with 6 main faces:     and I added some detail to one side:    How can I copy what's on that one face to the 5 other faces? I know I can mirror to have a copy on the opposite side, but what about the other 4 faces?  While taking screenshots for the question, I managed to figure out how to make it work for uniform/regular shapes. I'm still interested anyone who has an answer for how to do this when the faces are not in regular locations.

I want to create a cube with some general extrusions. This should be the same across all sides of the cube. Is there a way to make this mirrored across all six sides? I know that I could delete the rest of the cube, copy my changes, rotate it 90°, move it down and to the side, and repeat for all the sides, then remove doubles, but I'm wondering if there's a way to make this work in real time.  In the below image, all six sides should copy the changes shown here on the one side:


I understand that both $\mathbb{N}$ and $\mathbb{N}\times\mathbb{N}$ are of the same cardinality by the Shroeder-Bernstein theorem, meaning there exists at least one bijection between them. But I can't figure out what such a bijection would be. The paper that I'm reading gives an example of an injective function $f:\mathbb{N}\to\mathbb{N}\times\mathbb{N}$, $f(n)=(0,n)$, and an injective function $g:\mathbb{N}\times\mathbb{N}\to\mathbb{N}$, $g(a,b)=2^a3^b$. I was thinking perhaps if there were some way to combine these two, I could find a bijection, but I have no idea how to go about that or if it's even possible.  What is an example of a bijection between these two sets, and please explain the process by which you found it?

Possible Duplicate:             I wanna know if $\mathbb{Z^+}\times \mathbb{Z^+}$ is countably infinite and how should one construct a bijection and check if it is a bijective function


I've been putting in the command: /give @p iron_pickaxe 1 0 {CanDestroy: ["diamond_ore"]}  I've been putting this into a command block. I've repeatedly tried to fix it, change it a little, re-enter it, I even destroyed the command block and tried a new one. Nothing worked. It's been saying the same thing: Line 1, Column 2 Missing: "}" or object member name  What am I doing wrong here?

This question was recently split into different questions for each workaround. See   meta posts for more information.   Can you use NBT tags in commands? I’ve tried commands that normally work in Java Edition like: give @s minecraft:planks 30 1 {display:{Lore:["Wooden planks"]}} give @s stone_pickaxe{Unbreakable:1b} give @s item_frame{EntityTag:{Invisible:1b}} summon villager ~ ~ ~ {Offers:{Recipes:[{buy:{id:"emerald",Count:5b},sell:{id:"diamond_sword"}}]}} summon tnt ~ ~ ~ {Fuse:20s}


I have a document I keep compiling, using latex and bibtex, and it automatically creates my reference page. My final page is references and I use two columns, so naturally, assuming the reference page is not full, I get a full left column and a less-than-full right column.  I need the reference page to be evenly spaced between the columns. I usually do the following: After compiling, I edit the .bbl file and insert \vfill\pagebreak after the 'middle' reference. The problem is that after each compilation I need to re-do this.  I'm sorry not to have an MWE but it would require uploading a complete library of references...   Appreciate any comments. Thanks, Ido.

I create a document in two-column-layout with LaTeX (and Koma-Script, if that is relevant). The two-column-layout is defined in documentclass. The last page of an chapter fills the left column first - the result is that both column are of different length. How can I balance that?  EDIT: flushend like mentioned in the answer of TH. doesn't work for me. Maybe it is conflicting with some other package I use?  EDIT 2: OK, after I tested with lipsum like suggested from Joseph Wright I saw it balanced. I tried a little bit and could find out, that flushend only balances the columns in the last chapter, not in all of them. Knowing that, I could see, that it is true for my document too, the last chapter has balanced columns. How can I achieve it for all of them? Here my short example:  \documentclass[a4paper, 10pt, twocolumn, DIV=18]{scrbook}      \usepackage{flushend}     \usepackage{lipsum}      \begin{document}      \chapter{test}          \lipsum         \lipsum      \chapter{second}          \lipsum         \lipsum      \chapter{third}          \lipsum         \lipsum  \end{document}


I had a hacking streak (sojourner) of 71 days and did my first hack of the day on day 72 (31 August), only to discover it had gone back to '0'. Why has this happened. I definitely did not miss the 24hr reset time as I was actually out and about 4 hours earlier than I would normally have been. To say I was really annoyed about this is an understatement!

Does the 24 hours timer start:     when you hack a portal on a particular day     or     does it use the calendar days and check if you did hack a portal on a particular day   or     does it simply use a fixed international timezone to calculate the 24 hour cycle   or     does it use the agent's hacking cell's timezone to start it?   If it's the calendar days method than the explanation of the badge would be a little bit misguided because you could hack a portal on 00:01 on Saturday and then hack another one on 23:59 on Sunday and it would be practically two days between two hacks.  If it's based on the agent's last hack for a particular day then the explanation still would be problematic?  The third option would be a little bit unfair (or timezone racist) for the rest of the world.  The last option (the cell's timezone) would/could be both unfair for travellers and/or non-travellers.  Does anyone know any details about it?


Say my last name is Soloniewicz and I'm writing a holiday card. Is it:   Happy holidays from the Soloniewicz's Happy holidays from the Soloniewiczs Happy holidays from the Soloniewiczes   I'm leaning towards the number three, but looking for input.

If I were to use the sentence "There are lots of John Smiths" in the world, would that be the correct use for saying that there are a lot of people named John Smith in the world?  I don't think there should be an apostrophe as that would imply ownership of something.  If my first example is correct, then what would you do if the name referenced already ended with an 's'?


I know that the $L^p$ spaces are reflexive for $1<p<\infty$. I want to explicitly show that $L^1((0,1),\mathbb{R})$ is not reflexive by finding an element of $L^1$** that is not in $L^1$. To be more precise:   There is a canonical embedding $J: X \rightarrow X^{**}$ that is given by   $$J(x)(y)=y(x)$$  I want to find an element of $L^1$** that doesn't get mapped to by $J$.

I want some proof for the following statement :  $L^1$ and $L^{\infty}$ are not reflexive.  Can anyone help me, please? or reference me?


I have always been surprised how confident Luke seemed to be when trying to rescue Han Solo from Jabba's palace.   It is fair to assume that training with Yoda boosted his Jedi skills. My understanding is that all that he trains with Yoda is what we see on screen, since in The Return of the Jedi he asks Yoda about what Vader told him in Bespin, a question Luke not refrain to ask when he had the chance (so there is no "off camera" training with Yoda between episodes 5 and 6).  I know that it is impossible to know how much training with Yoda improved Luke's abilities, but maybe it is possible to know for how long he trained with him?  My recollection from watching The Empire Strikes Back is that there is no good or reliable way of measuring the time our heroes spend either imprisoned in Bespin or in Dagobah, but maybe I missed something or there are other sources that can answer the question of how long does Luke Skywalker train with Yoda?

From the answer to the question  :     We also don't know how much time Luke spent training.   I tried to check some references like  and  related section on their Wookieepedia articles, but there is not even a clue of the amount of time he spent there.  Is there any canon information on the subject? Or any extrapolation of how long Luke's journey on Dagobah was? Was it a day? Several weeks? Some months?


For example we have α, β belongs to $\Bbb R$, then how to show that the following system of linear equations will have infinite many solutions whenever β belongs to $[−\sqrt 2,\sqrt2]$?    $$\left\{ \begin{align} -x + \sin \alpha\,y - \cos\alpha\,z=0,\\     \beta\, x + \sin \alpha\,y + \cos\alpha\,z = 0,\\     x + \cos\alpha\,y + \sin \alpha\,)z= 0. \end{align}\right.$$

I have a question where $\alpha$ and $\beta$ are elements of $\Bbb R$, and I have to show that a system of linear equations will have infinitely many solutions whenever $\beta$ is an element of $\bigl[ -\sqrt 2, \sqrt 2\bigr]$.  There are three variables that have values like $\sin\alpha,\cos\alpha, \beta x$, etc. Now I know how to solve regular multi-variable linear equations to check if a linear system has infinite solutions or not, but this one is really tricky.... I don't even know where to start.   PS. I am really bad at math,  I don't even know how to read notations.   Here's the actual question:   Let $\alpha$, $\beta$  $\in$ R; then show that the following system of linear equations, will have infinite many solutions whenever $\beta$  $\in$ [- $\sqrt 2$, $\sqrt 2$ ];  $\  - x + (\sin \alpha )y - (\cos \alpha )z = 0\\ \beta x + (\sin \alpha )y + (cos\alpha )z = 0\\  x + (cos\alpha )y + (sin\alpha )z = 0 $


In my campaign, there is one player that play a Goliath Runic Knight, and has a 20 in Strength. Having the possibilty to get a size bigger with Gigantism, and counting another size bigger that he really is for pushing, draging and lifting things with Powerful Build.  Rules tells he can possibly lift something that weight around 900kg/2000lbs (or 1200kg/2600lbs, not 100% sure about the math on this one), and with this power house of a man, i'm 100% sure that the question "how far can i throw this character/monster/object/Hot-dog stand" is going to pop up.  The problem is, i don't have an answer for that, for specific object, like weapons or throwable, it's usually written in the rules, but i find nothing on throwing the party's dwarf, so i require a bit of help there.  Also, does anyone know if there is a chart or something for damage taken if this man throw a creature on, say a tree (or a tree on a creature), or i will just have to guess ?  Thanks a lot.

For example, if there is a lava river surrounding a castle. There is a drawbridge that can be lowered, but the lever is on the other side. PCs couldn't find a hidden passageway,either because PCs failed necessary check and couldn't find it or just because there isn't one. They don't have rope to try to pull the lever down. Or if PCs want to rob a house, but can't pick a lock, they see that window on the second floor is open. Can one PC use his Strength to throw another PC that is one size smaller, with other PC using his Dexterity or Strength to not fall down or lose balance?


I have this example from an official site: char* variable1; variable1=getenv ("PATH"); if (variable1!=NULL) {  printf("variable1=%s",variable1); } //Shouldn't this be here to avoid memory leak? //delete variable1;  Or we can say that the pointer variable get its value in an equation and there is no need for deallocation because there is no allocation?

What is the difference between new/delete and malloc/free?  Related (duplicate?):


Currently I have ubuntu 13.04 64bit installed on my 320gb partition. All of my work, music and videos are stored in the video and music folders. Is there any way to reinstall Ubuntu 13.04 again without losing my data?

I want to reinstall Ubuntu keeping my data intact. I have 160 GB hardrive (sata or pata I don't know but it's slim and made in China) with a 40 GB ext3 partition, a 4GB swap memory and 3 other partition with a FAT32 file system. I have around 4GB space on my drive where Linux is installed.  I'd like to keep the data intact, especially the Downloads folder, desktop, and /var/www; And I no longer have access to any other machines or external storage devices.


This is the test case: ARMOIRE 6 PORTES &lt;span style=&quot;font-family: arial;&quot;&gt;&lt;u style=&quot;color: rgb(170, 170, 170);&quot;&gt;:	Longueur : 297 cm - Profondeur : 73 cm - Hauteur : 260 cm.&lt;/span&gt;&lt;br&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td&gt;&lt;b&gt;&lt;u&gt;ARMOIRE 4 PORTES &lt;span style=&quot;font-family: arial;&quot;&gt;&lt;u style=&quot;color: rgb(170, 170, 170);&quot;&gt;:

Chevet  And here's my solution: (?<=&)(?!.<).?(?=[A-Z]) Basically I want to select everything between a & and the first instance of [A-Z], but not if it contains a html tag bracket. At first I thought it doesn't work, because it didn't - not in Notepad++, not on regex101.com However, if I modify the test string ARMOIRE 6 PORTES &lt;span style=&quot;font-family: arial;&quot;&gt;&lt;u style=&quot;color: rgb(170, 170, 170);&quot;&gt;:	Longueur : 297 cm - Profondeur : 73 cm - Hauteur : 260 cm.&lt;/span&gt;&lt;br&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td&gt;&lt;b&gt;&lt;u&gt;ARMOIRE  4 PORTES &lt;span style=&quot;font-family: arial;&quot;&gt;&lt;u style=&quot;color: rgb(170, 170, 170);&quot;&gt;:

Chevet  then it works.  I would like to understand why and how I can modify my regex to cover both cases - if possible.

I know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, is it possible to match lines that do not contain a specific word, e.g. hede, using a regular expression?   Input:  hoho hihi haha hede   Code:  grep "<Regex for 'doesn't contain hede'>" input   Desired output:  hoho hihi haha


So based on this thread :   which was asked 7 years ago, the answer says      "Entanglement is being presented as an "active link" only because most   people - including authors of popular (and sometimes even unpopular,   using the very words of Sidney Coleman) books and articles - don't   understand quantum mechanics"   if so, then how has china developed a technology where they transmitted data via Earth-to-space quantum entanglement?      also some other countries have said that they developed a technology where they transmitted data in a less of a  distance   so am i missing something here?   also not sure how is this the duplicate of my previous question when my previous question is the duplicate of a thread that was posted 7 years ago and now I'm responding to that, basically if someone asks a question even after 7 years no one can ask a question about that thread?

So I'm an IT engineer and i just watched a video about Quantum entanglement, that somehow when we split the entangled photons, any change happening to one of them will be reflected to the other one INSTANTLY, and therefore we can use this technology to transfer data from one point to the other instantly, basically even faster than the speed of light because no travel is required so we can even send data without the need of encryption!!   and  China has developed a technology like this too   so since i have 0 knowledge about quantum  physics and this blows my mind, can someone here explain this in a simple manner that how is this possible? and does this mean we can communicate with other planets INSTANTLY no matter how far they are ? doesn't this change everything?  also what is this technology called? where we separate the entangled photons and use them to communicate, basically can you guys also tell where should i start because i want to know everything about this technology, but I'm not sure where to start!


I have a question on a comment from Daniel Hyubrechts' Complex Geometry  on pages 133/134.  Let $X$ be a compact Kähler manifold. Consider the exponential sequence on cohomology   $$ ... \to H^1(X,\mathcal{O}_X^*)=Pic(X) \to H^2(X, \mathbb{Z}) \to H^2(X, \mathcal{O}_X) \to ...$$     Remark 3.3.3 Often, the image of $Pic(X) \to H^2(X,\mathbb{R}) \subset H^2(X,\mathbb{C})$ is called the Neron-Severi group $NS(X)$ of the manifold $X$. It spans a finite dimensional real vector space $NS(X)_{\mathbb{R}}= NS(X) \otimes \mathbb{R} \subset  H^2(X,\mathbb{R}) \cap H^{1,1}(X)$, where the inclusion is strict in general. The Lefschetz theorem above thus says that the   natural inclusion $NS(X) \subset H^{1,1}(X, \mathbb{Z})$ is an equality.      If $X$ is projective, yet another description of the Neron-Severi group can be   given. Then, $NS(X)$ is the quotient of $Pic(X)$ by the subgroup of numerically   trivial line bundles. A line bundle $L$ is called numerically trivial if $L$ is of   degree zero on any curve $C \subset X$.    Q1: Why in case of $X$ projective i.e. closed subscheme of projective space, these two descriptions of Neron-Severi group coincide? Thus why the image of $Pic(X) \to H^2(X,\mathbb{R})\subset H^2(X,\mathbb{C})$ coincides with quotient $Pic(X)/A$ with $A$ subgroup of numerically trivial line bundles?  Q2: Why $NS(X)_{\mathbb{R}} $ is contained in $  H^{1,1}(X)$. Recall, we have decomposition $H^2(X, \mathbb{C})=H^{2,0}(X) \oplus H^{1,1}(X) \oplus H^{0,2}(X)$.

Let $X$ be a smooth projective variety over $\mathbb{C}$, then the Neron-Severi group $NS(X)$ of $X$ is defined to be the Picard group of $X$ modulo algebraically equivalent relations.   On the other hand, by the exponential sequence, there is a first Chern class map  $$c_1: {\rm Pic}(X) \to H^2(X, \mathbb{Z}).$$ It is claimed that the image of $c_1$ coincides with $NS(X)$.   I want to know why this is true. Any suggestion or reference is greatly welcome!


I have to find  $$I=\int_{0}^{\pi}\ln(1-2a \cos x+a^2)\,dx$$  Can someone help me to solve it?

For $a\ge 0$ let's define $$I(a)=\int_{0}^{\pi}\ln\left(1-2a\cos x+a^2\right)dx.$$ Find explicit formula for $I(a)$.   My attempt: Let  $$\begin{align*} f_n(x) &= \frac{\ln\left(1-2 \left(a+\frac{1}{n}\right)\cos x+\left(a+\frac{1}{n}\right)^2\right)-\ln\left(1-2a\cos x+a^2\right)}{\frac{1}{n}}\\ &=\frac{\ln\left(\displaystyle\frac{1-2 \left(a+\frac{1}{n}\right)\cos x+\left(a+\frac{1}{n}\right)^2}{1-2a\cos x+a^2}\right)}{\frac{1}{n}}\\ &=\frac{\ln\left(1+\dfrac{1}{n}\left(\displaystyle\frac{2a-2\cos x+\frac{1}{n}}{1-2a\cos x+a^2}\right)\right)}{\frac{1}{n}}. \end{align*}$$ Now it is easy to see that $f_n(x) \to \frac{2a-2\cos x}{1-2a\cos x+a^2}$ as $n \to \infty$. $|f_n(x)|\le \frac{2a+2}{(1-a)^2}$ RHS is integrable so $\lim_{n\to\infty}\int_0^\pi f_n(x)dx = \int_0^\pi \frac{2a-2\cos x}{1-2a\cos x+a^2} dx=I'(a)$. But  $$\int_0^\pi \frac{2a-2\cos x}{1-2a\cos x+a^2}=\int_0^\pi\left(1-\frac{(1-a)^2}{1-2a\cos x+a^2}\right)dx.$$ Consider $$\int_0^\pi\frac{dx}{1-2a\cos x+a^2}=\int_0^\infty\frac{\frac{dy}{1+t^2}}{1-2a\frac{1-t^2}{1+t^2}+a^2}=\int_0^\infty\frac{dt}{1+t^2-2a(1-t^2)+a^2(1+t^2)}=\int_0^\infty\frac{dt}{(1-a)^2+\left((1+a)t\right)^2}\stackrel{(*)}{=}\frac{1}{(1-a)^2}\int_0^\infty\frac{dt}{1+\left(\frac{1+a}{1-a}t\right)^2}=\frac{1}{(1-a)(1+a)}\int_0^\infty\frac{du}{1+u^2}=\frac{1}{(1-a)(1+a)}\frac{\pi}{2}.$$ So $$I'(a)=\frac{\pi}{2}\left(2-\frac{1-a}{1+a}\right)\Rightarrow I(a)=\frac{\pi}{2}\left(3a-2\ln\left(a+1\right)\right).$$  It looks too easy, is there any crucial lack?  $(*)$ — we have to check $a=1$ here by hand and actually consider $[0,1), (1,\infty)$ but result on these two intervals may differ only by constant - it may be important but in my opinion not crucial for this proof.


I would like to know if there is a solid state device I can use to back up my digital files without a computer when I am traveling.

This question seems similar to , but my needs are different :   I shoot in RAW exclusively I'm looking for a 100% offline solution: while traveling, Internet won't be accessible the "laptop" solution is too heavy for me: I'm looking for a lightweight solution the simplest, the better: one device to rule them all   EDIT:  I'm using good old Compact Flash cards (yes, the bigger ones), so I need a device that can read it. If it can read from other cards, this question might be interesting for more people than myself  - that's the whole purpose of the website.    Also asked by :  Portable Storage Device while traveling  I need storage device which is able to read CF cards and make a backup of my photos while traveling. I do not want to carry laptop (it's bulky) and tablet (too little storage) but looking into some other solutions.   So far I found:   Epson PXXXX - price is blocker for me Jobo Giga Vu - same as above Nexto DI - bit better, but still a lot Hyperdrive Colorspace UDMA - this looks the best for price/options Wolwerine PicPac - cheap, bad opinions DigitalFoci PhotoSafe - same as above Ex-Pro® Picture 2 Drive - didn't find much about it   So ladys & gents what do you use?


Recently started using Ubuntu, just wondering how to change my computer name.  as when i made my account, it says at the end of it "default-string"   name@name-Default-string

When I connect to my server (ubuntu server 10.10), I get this:  name@server-name.belkin ~>   How can I remove ".belkin"?


Can I proof this identity somehow without using the Riemann integral?  I have tried Stolz–Cesàro Theorem and sums of valuations' progressions.

How to prove the following equality? $$\sum_{n=1}^{\infty}\frac{1}{\prod\limits_{k=1}^{m}(n+k)}=\frac{1}{(m-1)m!}.$$


In beamer class, when i compile using LaTeX, the output pdf results perfectly the way i expect it to. But when i change it to XeLaTeX, in the lstlisting environment, every tab in the code results in a "^^I"-Placeholder (See output-pdf below). How do I fix this?   if( Bedingung ) {  ^^I//Code, der nur ausgefuehrt wird, wenn die Bedingung wahr ist   }  ^^I^^I   LaTeX-Code (Reduced to the minimum, one frame as an example):  \begin{document}     \begin{frame}[fragile]{if-Statements}         \begin{block}{Syntax}                \begin{lstlisting} if( Bedingung ) {     //Code, der nur ausgefuehrt wird, wenn die Bedingung wahr ist }                    \end{lstlisting}         \end{block}         \begin{block}{Logik}                 \begin{itemize}                  \item Alles innerhalb eines if-Blocks wird nur ausgeführt, wenn die Bedingung (in Klammern) wahr ist.             \end{itemize}         \end{block}     \end{frame} \end{document}

I'm trying out  with gnuplot to generate the data.  This works by having pgfplots write some stuff to an external file, run gnuplot on the file, and then use the generated data to plot the graph.  The problem I'm having is that I get different behaviour under xelatex as pdflatex or lualatex.  In xelatex, the data file is littered with ^^I whereas in the other two formats these are tabs.  It appears that the code ^^I is getting stored as a macro which then gets written out to the file, so possibly there's something funny going on with the ^^I syntax: xelatex is reading it literally.  Indeed, when I do \show\pgfplots@TAB (the macro in question) then for pdflatex and lualatex then I get a literal tab whereas for xelatex I get ^^I.  So how do I get a tab in xelatex?  And why isn't \gdef\pgfplots@TAB{^^I} working?  (The previous line in the code, by the way, is \catcode`\^^I=12 - I don't know if that has anything to do with it.)


I'm looking for a way to calculate the values shown in cols D & E in the below screengrab.  Column D contains the earliest date from column B where the name in column A matches.  Similarly, column E contains the latest date from column C where the name in column A matches.    e.g. For all instances of "Bob" in column A: column D should contain the earliest "Line from date" from column B where column A="Bob" (in this case 1st December 2013).  I know this can be done easily using a pivot table, however in this case I need to do it with either a formula or programatically.  The data is being generated using VBA so, in the absence of a formulaic solution, I will simply revert to calculating the required values as part of the program (NB: I am not asking how to do this).  Because of the dataset's complexity (the above example is a gross simplification) it would take me about a day to implement it in code so I'd rather avoid that if possible.  I'm guessing the way to go might be array formulas, but I am ashamed to admit I haven't the first clue how to use them.  Any and all help/pointers greatly appreciated.

I have a sheet that contains 365 rows, representing dates from a referred Start Date (for the following year). There are about 30 columns each of which has an agency name. The cells in the sheet contain calculated agency populations for each date.   This is a reference sheet: "DailyPopulation"  In the ReportSheet the user defines a Period Start Date and Period End Date  I'm trying to construct an array formula that displays the max population for each agency within the defined period, separately (of course) I also want the min.


Need a hint to compute $\displaystyle \sum_{x=0}^\infty xa^x$ and $\displaystyle \sum_{x=0}^\infty x^2a^x$, where $a \in (0,1)$.

I am very confused about how to compute  $$\sum_{n=0}^{\infty}nk^n.$$  Can anybody help me?


If $\text E$ is an arbitrary closed set in $\mathbf R^n$, show that there is an $\text f\in \text C^\infty(\mathbf R^n)$ such that $\text f(x)=0~$for every $x \in \text E$ and $\text f(x)>0$ for every other $x\in \mathbf R^n$.  My approach is as follows :  Since $\text E$ is given to be closed hence $\text E^c=\text V$ will be an open set in $\mathbf R^n$ and hence $\text V$ can be written as countable union of open sets $\{\text V_i\}_{i=1}^{\infty}$ and hence one can have a partition of unity $\{\psi_i\}_{i=1}^{\infty}\subset \text C^\infty (\text V)$ such that $\text {supp}(\psi_i)\subset \text V_i$. Then if i take $f=\Sigma_{i=1}^{\infty} \psi_i$ then my this $\text f$ is in $\text C^\infty (\text V)$ and $f(x)>0$ in $\text E^c$ and $f(x)=0$ in $\text E$. Now i am just left with to show that $f\in \text C^\infty (\mathbf R^n)$ or how can i generalize my $f$ to get the desired result.  Any type of help will be appreciated. Thanks in advance.

In Walter Rudin's Principles of mathematical analysis Exercise 5.21, it is proved that for any closed subset $E\subseteq \mathbb{R}$, there exists a smooth function $f$ on $\mathbb{R}$ such that $E=\{x\in \mathbb{R}\mid f(x)=0\}$.   Since $E^c$ is open in $\mathbb{R}$, $E^c$ is a countable disjoint union of open intervals $(a_i,b_i)$. On an interval $(a,b)$, if we let $f(x)=\exp(\frac{1}{(x-a)(x-b)})$, $x\in(a,b)$; $f(x)=0$, $x\notin(a,b)$, ($f(x)=\exp(\frac{1}{(x-a)})$ or $f(x)=\exp(\frac{1}{(x-b)})$ on $(a,\infty)$ and $(-\infty,b)$ resp.), then $f$ is smooth. Hence we can get a smooth function on $\mathbb{R}$ such that $E$ is the zero point sets of $f$.  (1). How about a closed subset $E$ of $\mathbb{R}^n$? is it true that for any closed subset $E\subseteq \mathbb{R}^n$, there exists a smooth function $f$ on $\mathbb{R}^n$ such that $E=\{x\in \mathbb{R}^n\mid f(x)=0\}$?  An open set in $\mathbb{R}^n$ cannot be written as a disjoint union of countable open balls hence the proof above is not valid. The partition of unity only claims that for an  open set $U$, there exists open $V$ in $U$ such that $\bar V\subseteq U$ and a smooth function $f$ on $\mathbb{R}^n$ such that $supp f\subseteq U$, $f|_V=1$.   (2). The taylor series of $f(x)=\exp(\frac{1}{(x-a)(x-b)})$ does not converge around points $a,b$ hence $f$ is not analytic at $a,b$. Is it true that for any closed subset $E\subseteq \mathbb{R}$, there exists an analytic function $f$ on $\mathbb{R}$ such that $E=\{x\in \mathbb{R}\mid f(x)=0\}$?


I have the zip codes for the US and their population. I need to calculate the weighted center. I have tried finding the zip code with the minimum   sum(distance_to_zip * zip_population)   This works but is slow. With 30,000 zip codes there are two loops, so 900 million calculations. I've tried to optimize by sorting based on distance from the middle, and stopping the inner loop once the value hits the current lowest value. This helps, but it's still too slow.  Is there a faster algorithm for calculating the weighted center?   Note: I am writing my own code, I'm not looking to do this in a GIS package.

While searching the web, solutions for finding centroids of polygons come up rather often. What I'm interested in is finding a centroid of a cluster of points. A weighted mean of sorts.  Can you provide some pointers, pseudo code (or even better, an R package that has already solved this) or links of how this issue can be tackled?    @iant has suggested a method to average coordinates and use that for the centroid. This is exactly what crossed my mind when I saw the right picture on .  Here is some simple R code to draw the following figure that demonstrates this (× is the centroid):  xcor <- rchisq(10, 3, 2) ycor <- runif(10, min = 1, max = 100) mx <- mean(xcor) my <- mean(ycor)  plot(xcor, ycor, pch = 1) points(mx, my, pch = 3)       cluster::pam()$medoids returns a medoid of a set of cluster. This is an example from @Joris Meys:  library(cluster) df <- data.frame(X = rnorm(100, 0), Y = rpois(100, 2)) plot(df$X, df$Y) points(pam(df, 1)$medoids, pch = 16, col = "red")


I deleted my Ubuntu partition on Windows drive manager and then tried to install it again, after which I was getting this error:  Failed to open \EFI\BOOT\mmx64.efi - Not Found Failed to load image \EFI\BOOT\mmx64.efi - Not Found Failed to start MokManager: Not Found Something has gone seriously wrong: import_mok_state() failed : Not Found   After this went and deleted my boot settings and now I can't install Ubuntu from my bootable usb. It always gets stuck on the screen where it asks me if I want minimal or normal installation. However Windows is booting up perfectly. Please help.

I tried to install Ubuntu 18.10 on my XPS 15 9570 earlier. Everything was working fine until I got to the partition selection part of the installation. That's when the installer crashed and I had to shut down my machine. I think it's because I had my SATA configuration set to RAID ON instead of AHCI, which is now fixed.  Now when I try to run the installer from my bootable USB I get the following error  Failed to open \EFI\BOOT\mmx64.efi - Not Found Failed to load image \EFI\BOOT\mmx64.efi: Not Found Failed to start MokManager: Not Fond Something has gone seriously wrong: import_mok_state() failed   Hoping someone might have some idea as to what is going on


I don't understand why this works. wouldn't the >>> let timeoutID <<<< reset the variable each time, so that the timeoutId is always empty? I would put the 'let' outside of this assuming that's the only way it would work. However this works, I just don't get it. This is from a Udemy course. I get everything else. I'm an amateur here, so..... const debounce = (func, delay = 1000) => {     let timeoutId;     return (...args) => {         if (timeoutId) {             clearTimeout(timeoutId);         }         timeoutId = setTimeout(() => {             func.apply(null,args);         },delay)     };  }; const onInput = event => {         fetchData(event.target.value);   }; input.addEventListener('input', debounce(onInput,1000));

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


I would like a tikz picture to move over to the left so it is touching the edge of the page.  Here is my code:  \begin{figure}     \resizebox{\paperwidth}{!}{         \begin{tikzpicture}             \fill[black!50!blue] (-10, 1) rectangle (10, 2);             \fill[black!50!blue] (-5, 0) rectangle (5, 3);         \end{tikzpicture}     } \end{figure}   This is what it looks like at the moment. How would I move it over?

I have a document containing a table which is slightly too wide for the page. But instead of growing to the right side only, I would like to have it centered on the page.  I have tried to use the center environment but this doesn't seem to help.


Suppose I have the following command to be parallelized:   my_command --file <(my | pipeline)   Now, I would like to parallelize in specific chunks:  my | pipeline | parallel --spreadstdin my_command --file <(parallel's stdin)   How would I accomplish this redirection with gnu parallel?

Per man definition, this command gets the input from a file.  $ command -r FILENAME   Suppose that FILENAME is a file containing a list of filenames, as it was generated using ls > FILENAME.  How can I, instead, feed the command with the result of ls directly? In my head something like this should be possible:  $ ls | command -r  But it doesn't, the output of ls doesn't get hooked as an argument. Output:  Usage: command -r FILENAME error: -r option requires an argument   How could I obtain the desired effect?


Case 1: when a player kicks the ball in soccer game  Case 2: When a fast bowler swing the ball in cricket  In both cases the ball makes a curvature. How this happens ? Is there any Law of Physics behind them? Does both the case undergoes same phenomenon?

Soccer players kick the ball in a linear kick, though you find it to turn sideways, not even in one direction. Just mid air it changes that curve's direction, i.e., it swings, as footballers say. Is there any physical explanation?    Maybe this video will better emphasize this phenomenon:


this lemma is a corollary of the following lemma: if $\gcd(b,c)=1$ $gcd(a,bc)=gcd(a,c)gcd(a,b)$

I've been stuck on this for far too long, but it isn't proved in my lecture notes so it's supposed to be elementary...  Let $x, y, z$ be integers such that $x$ divides $z$, $y$ divides $z$ and $x$ and $y$ are relatively prime, then $xy$ divides $z$.  Thanks a lot !


I want to know is there any API which I can use to select both file and/or folder in C#. I have read some docs where people are suggesting to write your own wrapper class and override the properties of both OpenFileDialog and folderbrowserdialog. But I don't want to do that. Does microsoft provide any such APIs which I can use ?

Is there an "easy" way to select either a file OR a folder from the same dialog?  In many apps I create I allow for both files or folders as input. Until now i always end up creating a switch to toggle between file or folder selection dialogs or stick with drag-and-drop functionality only.   Since this seems such a basic thing i would imagine this has been created before, but googling does not result in much information. So it looks like i would need to start from scratch and create a custom selection Dialog, but I rather not introduce any problems by reinventing the wheel for such a trivial task.  Anybody any tips or existing solutions?  To keep the UI consistent it would be nice if it is possible to extend the OpenFileDialog (or the FolderBrowserDialog).


In baking chocolate marshmallo logs, the recipe calls for 3 sq of semisweet chocolate.  In the  new packaging box, how many  squares do I now use?

I feel like a real dummy but I need some help.  I have a recipe that is calling for 8 oz of semi sweet chocolate finely chopped.  I'm thinking that means a semi sweet chocolate  bar chopped up.  I read where a lady said each square is an ounce of chocolate but on the box it says there is 4 ounces  but I bought the box and when I got it home and opened it, there are 8 squares in it.  Why does the box say 4 ounces if each square is an ounce and there are 8 squares?


I'm personalizing an email based on a First_Name field, however, due to some email capture forms that only have a Full_Name field rather than it split out between two fields, first and last name, I'm trying to figure out how to ONLY display the first name from the Full_Name field. For example:  Full_Name: Jane Doe  I just want "Jane" to display in the email. Is there an AMPScript function that can be used similarly to the LEFT function in Excel to look up the space and display the characters before it?  Thanks!

Is there an AmpScript function that can be used in an equivalent manner to sql left, right and mid functions?   Thanks, Mark


I am unable to understand how the output of the below code is "-3" ?  #include <stdio.h> void main() {     int a = -5;     int k = (a++, ++a);     printf("%d\n", k); }   What is the concept behind this  int k = (a++, ++a); statement in c or c++?


I'm starting up my first online service. I will run on a MEAN stack running on Linux on AWS.  It is time now to guarantee my service will be running smoothly on a 24x7 basis. For Mongo, I'go to mlab for database replication. In AWS, i will put 2 servers on different locations on a failover mode. For resources monitoring I will go to Site24x7 or similar service.  All fine, but my worries is related to intervention in case of failure. As the company is a startup and there are only the partners involved, we will be mainly involved on travelling doing sales, marketing. Newer features will be done on "extra time" or through oursourcing. We also don't have much money to spend for now.  So, my questions are:  a) Does the described architecture is enough to be safe about the service stability or should I think of something else ?  b) Should I go for failover between AWS and other providers? If so, is there a tool to do it automatically?  c) Should I need a person to handle unexpected events on a daily basis? For now we don't have money to it, so what are the alternatives to having this person ?  I'm not worried now about capacity planning, but how to keep my environment running.  My expected SLA is of some minutes downtime, not more than half an hour.

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


If an anti-matter singularity and a normal matter singularity, of equal masses, collided would we (outside the event horizon) see an explosion?

Let's say we have one black hole that formed through the collapse of hydrogen gas and another that formed through the collapse of anti-hydrogen gas. What happens when they collide? Do they (1) coalesce into a single black hole or do they (2) "annihilate" into radiation?  One would expect (1) to be the case if the No Hair Theorem were to hold. So I guess what I'm really asking for is a modern understanding of this theorem and its applicability given what we know today.


I have this:  $(".sf_sub_accordian, .sf_find_container").bind("click", function(event) {     event.stopPropagation(); });   But it stops working when I add content dynamically via ajax-call.  How to make bind work with dynamically created content?  Edit: Without success I have already tried this:  $(document).on("click", ".sf_sub_accordian, .sf_find_container",function(event) {         event.stopPropagation(); });   In fact, it doesn't work at all if I do it like that.

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.


Once I open canned tomatoes and transfer it to a glass jar, what is the rate of deterioration of their lycopene content?

How do I know if a given food or ingredient I have is still good, or if I should discard it?  How can I best preserve a food or ingredient?     This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.


Im playing a 9th Beast Heart Adept with a couple of dips into other classes and i wanna know if there's any feat or magical items of the sort that boost the minions that Beast Heart Adept get since it apparently does not stack with other class-levels that give you animal companion, so here's my questions.   So is there anything that boosts animals from Beast heart adept? Is there any items that boost hd of either animal companions or just boost hd in general?

I'm playing a marshal 1/totemist 4/beast heart adept 9. Since I'm nearly done with the prestige class , I need some advice:   Do any classes continue what beast heart adept started with its monstrous companions? Are there feats or magic items that improve upon what the beast heart adept can already do?


I am trying to make a 1km square grid using QGIS 2.18.26.   I am using EPSG:4326. I need it to be exactly 1km square because that's how the variable data has been collected.   I am struggling to get the grid to be exactly 1km square, I have attempted using Vector Create Grid, and MMQGIS create grid layer, but I am unsure how to set the grid units to 1km square.

How do I create a fishnet shapefile using QGIS?   The equivalent task of "Create Fishnet" in ArcGIS.


Possible Duplicate:          In the SE dropdown inbox list, when you view it, all unread comments/answers get toggled to 'read' if you view one of them. Is there a way (of course there is; is there any support behind...) to make this per item rather than global? To set to read by comment/answer instead of all at once?   My reasons are duplicated in  but somehow the answer interpreted that question as simply asking for this as a preference. I am asking for this as the way to do things. Similar to how in RSS or news group readers you know what you've attended to and what not attended to.

The StackExchange™ MultiCollider SuperDropdown™ says I've got replies, but I've already viewed those.


I'm hoping to add a tikz-specific language environment to my LaTeX editor (vscode), I've run into a bit of an issue looking for any speicifications for tikz grammar though.  Would anybody know of any pre-existing tikz language grammars, or useful information? I don't feel I know enough to just work it out.  To clairfy I'm not looking for robust syntax error detection as in . The end goal here is syntax highlighting and autocompletion.  Thanks,  tecosaur.

Even further, I would be happy to see a definition of the tikz language in the usual manner programming languages such as Java and Pascal are defined.   The reason I ask is that I keep getting mysterious error messages for the tiniest typos. Essentially, incorrect use of the underlying languages leads to a "crash" of the compiler. This crash sometimes gives useful error messages, but sometimes they are hard to decipher.


Let $V,W$ be vector space over field $k$. Then  \begin{eqnarray*} V^*\otimes W &=&V^*(\oplus_{i\in I} k_i)\\ &=&\oplus_{i\in I}(V^*\otimes k_i)\\ &=& \oplus_{i\in I}V^*_i\\ &=& \oplus_{i\in I}Hom(V,k)_i, \end{eqnarray*} \begin{eqnarray*} Hom(V,W)=Hom(V,\oplus_{i\in I}k_i). \end{eqnarray*} When $W$ is finite dimensional, we have $Hom(V,\oplus_{i\in I}k_i)=\oplus_{i\in I}Hom(V,k)_i$. Thus $V^*\otimes W=Hom(V,W)$.   Does the equality holds when $W$ is infinite dimensional and $V$ finite dimensional? Is the equality holds when $W$ is infinite dimensional and $V$ also infinite dimensional?   I am confused. By universal property I only obtain $ Hom(M,\Pi_{i\in I}N_i)=\Pi_{i\in I}Hom(M,N_i)$. Can we obtain $Hom(M,\oplus_{i\in I}N_i)=\oplus_{i\in I}Hom(M,N_i)$ in general?   Thanks.

It's well known that $U^*\otimes V\cong L(U,V)$ for finite dimensional spaces. However, why people say that $U^*\otimes V$ is not isomorphic to $L(U,V)$ for infinite dimensional spaces and many books don't say anything related to this?


I'm writing a game in java and all is working more or less well, as you would expect when coding, but one issue I have come across is reading the image and sound files into the game. I wrote a method that works really well within Eclipse, but as soon as I try to test it in a runnable jar (exported using Eclipse) my game gets stuck on the loading screen because it can't read the files. I realized the problem there being that you cannot create File objects within a Jar, you have to use streams. This could work, but the images/sounds are located within folders and I'm not very sure how you can read files within a folder with streams(i.e not knowing the amount of files). Because of this I have tried to rewrite the method using the ZipInputStream (I found this as recommended when looking for solutions prior to posting this). This is what the method looks like now:  imageMap = new HashMap<String, BufferedImage>();     String imagebase = "/images";     CodeSource src = PlatformerCanvas.class.getProtectionDomain().getCodeSource();     if(src != null)     {         URL jar = src.getLocation();         try         {             ZipArchiveInputStream zip = new ZipArchiveInputStream(jar.openStream());             ZipArchiveEntry ze = null;             while((ze = zip.getNextZipEntry()) != null)             {                 System.out.println(ze.getName());                 if(ze.getName().startsWith(imagebase) && ze.getName().endsWith(".png"))                 {                     loading++;                     imageMap.put(ze.getName().replaceAll(imagebase + "/", ""), ImageIO.read(this.getClass().getResource(ze.getName())));                 }             }             zip.close();             System.out.println("Finished Loading Images");         }         catch (IOException e)         {             e.printStackTrace();         }     }   However, this completely skips over the while loop because getNextZipEntry return null. I tried using the base Zip archive libraries, but someone recommended the Apache Commons libraries, but neither worked. My Jar setup is this:  Jar /game/gameClasses /images/imageFiles /sounds/soundFiles /whateverOtherFoldersEclipseCreated   So my question is this: Why isn't this current method working and how do I fix it? Or, how can I load the images/sounds in a different way that works? I have looked at many other questions and tried many different things, but none worked for me.

I'm trying to access an XML file within a jar file, from a separate jar that's running as a desktop application.  I can get the URL to the file I need, but when I pass that to a FileReader (as a String) I get a FileNotFoundException saying "The file name, directory name, or volume label syntax is incorrect."  As a point of reference, I have no trouble reading image resources from the same jar, passing the URL to an ImageIcon constructor.  This seems to indicate that the method I'm using to get the URL is correct.  URL url = getClass().getResource("/xxx/xxx/xxx/services.xml"); ServicesLoader jsl = new ServicesLoader( url.toString() );   Inside the ServicesLoader class I have   XMLReader xr = XMLReaderFactory.createXMLReader(); xr.setContentHandler( this ); xr.setErrorHandler( this ); xr.parse( new InputSource( new FileReader( filename )));   What's wrong with using this technique to read the XML file?


I have data in MySQL such as "регистрацией в партнерской" but when it comes out in PHP echo'ed out it comes out as ????. My issue here is that I believe I have tried the obvious (see list below), so what else could I be missing?   SET NAMEs is UTF8 in Mysql There is a  header I have tried with/without utf8_encode / utf8_decode I've tried mb_convert_encoding My table (Innodb) charset is utf8 with utf8_general_ci   If this is a direct duplicate please show me but I think I've hopefully covered the initial checks I should have!

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Prove that $m^3 \leq 2^m$ for $m \geq 10$  This is my shot  Proof  We prove this by induction.  Basic step: For $n=10$ is $10^3 \leq 2^{10} = 1000 \leq 1024$ and that is correct.  Induction step: Assume that $k \geq 10$ and that the statement is true for each $10 \leq j \leq k$. We need to proof that it is also true for $k+1$.   So          $$(k+1)^3 \leq 2^{k+1} \Rightarrow k^3 + 3k^2 + 3k + 1 \leq 2^k + 2^k \underbrace{\Rightarrow }_{\text{induction hypothesis}} 3k^2 + 3k + 1 \leq 2^k$$  Now I don't understand how I can prove the rest.

Problem  For what natural numbers is $n^3 < 2^n$?  Attempt @ Solution   For $n=1$, $1 < 2$ Suppose $n^3 < 2^n$ for some $n = k \ge 1$ It looks like the inequality is true for $n = 0$, $n = 1$ and $n\ge10$ But, how can I prove this through induction?


Einstein discovered from studying the electrodynamics of moving bodies, that the speed of light $c_{em}$ is the same for observers, which move relative to each other with a constant velocity. But why must the speed of light be also the universal speed limit for all the other fundamental interactions (gravity, weak and strong force)? Why must $c_{em} = c_{g} = c_{weak} = c_{strong}$ ?

I suppose there was a discussion already on .  But I silly wonder whether all the massless mediators of four fundamental forces, i.e.  Graviton: $g_{\mu\nu}$ (gravity)  Photon $\gamma$: $A_\mu$ (electromagnetism)  Gluons: $A_\mu^a$ (strong interactions)  Necessarily travel at the same speed? Is there a no-go theorem or theoretical proof to say that it is impossible to have these three mediators have different speeds?   Or does QCD confinement makes the story of gluons any different from gravitons and photons?  [ps. excluded massive $Z^{0}$ and $W^{\pm}$ bosons (weak interactions)]  Another way to say this: Speed of photon, graviton, gluon all equal to $c$? or  Whether all massless particles necessarily have the same speed?  Note add: Notice however, in condensed matter systems, there can be emergent gauge fields and emergent massless particles (Dirac or Weyl cones), but their speeds need not be the same, unless there is some emergent symmetry...


Developer options not showing after build number pressed 7 times. It even says that the developer is turned on already, but when I search for it under "about phone" on the setting app, it doesn't show up. My purpose is to turn on OEM.  Can someone help? thanks!!

I have a Huawei nova 3i and I remember unlocking developer options when I first got the phone a few months back. Problem is now I have noticed that the developer options are gone so I went to build number and went to press it 7 times but after the first press it says (you are already a developer) but the option is still not there. I have looked online for at least an hour but can find nothing. Any help would be appreciated thanks


I have an application that makes extensive use of STL vectors and Boost multiarrays. The application is very sensitive to performance since it profiles large amounts of data in real time.   Since vectors and multiarrays do out of bounds checks, I would expect to incur some performance penalty as a result. I was wondering if there was a way to allow error checking only during development, but disable it in production.   So, I would like to know if this is indeed possible, and whether it would make a difference to the performance of my containers?

In our C++ course they suggest not to use C++ arrays on new projects anymore. As far as I know Stroustroup himself suggests not to use arrays. But are there significant performance differences?


I have a class that contains methods that query the database for information and then return a variable which value is the prepared version of the sql query,  after "execute()" and "setFetchMode()", the function returns that same variable.   In another file I create an object of that class, and call that method which I assign as the value of another variable so that I can fetch() it on a while loop. The problem is that all of that happens without any apparent errors but the data that I request from the database is not retrieved.  <?php class DatabaseContent{      private $sql = "SELECT * FROM :table ";      public function fetchAllRows($table, $rowOrder, $direction, $conn){         $this->sql .= "ORDER BY :roworder :direction ";         $q = $conn->prepare($this->sql);         $q->execute(array(':table'=>$table, ':roworder'=>$rowOrder, ':direction'=>$direction));         $q->setFetchMode(PDO::FETCH_ASSOC);          return $q;     }   And this is the file where I create the object  <?php                    $table = "topics";                    $rowOrder = "topic_id";                    $direction = "ASC";                     $q = new DatabaseContent;                     $n = $q->fetchAllRows($table, $rowOrder, $direction,$conn);                              while($row = $n->fetch()):                                 echo '
'.$row['topic_name'].'
';                             endwhile;                 ?>

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


There are two Butterknives in the About dialogue of the official Stack Exchange app for Android. They differ by URL, though.   App Version: 1.0.89 Device Manufacturer: samsung Device Model: SM-G357FZ   OS Version: 4.4.4 (G357FZXXU1AOG1)

Butterknife appears twice in the OSS attribution list of the Android app (v1.0.85). Based on the links, the second one should be JMustache.


I would like to know, how can a user become a Stack Exchange employee? What if I've asked a lot of questions and earned good badges and a lot of points? How is it possible? I've read Stack Exchange employs some users to post questions and answer answers. Is this true? What about other jobs with Stack Exchange, what are they, and how could it be possible to get them?  Thanks.

I am trying to get a job as a Stack Exchange system administrator and programmer. Where should I go to sign up for the job?


What's the quickest way from Gatwick airport to Paddington station? I would like to travel as less as possible, if there is a opportiunity it would be great when there is a direct connection? ( To take a cab is the last thing I'd do )

What's the most straightforward way to get from Gatwick airport to Paddington station in London using public transport?   I'm mostly interested in travel time & general smoothness of the trip (e.g. buying just one ticket for the whole trip would be nice). Price is a secondary concern.


I would like to upload public images for a web app to a service like AWS S3 or Google Cloud Plateform. This is going to be public images like user profile picture, homepage images... so there is not point making a private bucket (I guess).  Is there a way on AWS or Google Cloud Plateform to prevent a user to do a kind of DDOS attack and kill my budget? A sort of rate limiting? Or something like "after $100 a day I want to block my bucket from access and stop being billed." ?

How can I protect my public images hosted on GCS from ddos attacks?  Does Google provide any protection, or should I pay for the bandwidth used by that attack?


I would like to draw a vertical line in the plot, indicating the mode of the left gaussian.   \documentclass{article}  \usepackage{graphicx} \usepackage{pgfplots} \usepackage{tikz}  \pgfmathdeclarefunction{gauss}{3}{%   \pgfmathparse{1/(#3*sqrt(2*pi))*exp(-((#1-#2)^2)/(2*#3^2))}% }   \begin{document} \begin{tikzpicture} \begin{axis}[   no markers,    domain=0:90,    samples=300,   ymin=0,   axis lines*=left,    xlabel=$x$,   every axis y label/.style={at=(current axis.above origin),anchor=south},   every axis x label/.style={at=(current axis.right of origin),anchor=west},   height=5cm,    width=12cm,   ytick=\empty,   enlargelimits=false,    clip=false,    axis on top,   grid = major,   hide y axis,   xtick distance=10   ]  \addplot [very thick,cyan!50!black] {gauss(x, 45, 5)};  \addplot [very thick,red!50!black] {gauss(x, 55, 5)};   \draw[dashed] (45,-10) -- (45,10); \end{axis}  \end{tikzpicture}  \end{document}   However what I do get is the picture, but without the line. Why?

Judging from the pgfplots manual I expected the following code to work:  \documentclass{article} \usepackage{pgfplots} \begin{document} \begin{figure}   \begin{tikzpicture}     \begin{axis}[       xmin=0,       xmax=4,       ymin=0,       ymax=4,       ]       \draw (1,1) -- (3,2);     \end{axis}   \end{tikzpicture} \end{figure} \end{document}   However, it doesn't - meaning that it seems the \draw command does nothing at all. I just get an empty axes with no line.    Can anyone shed some light on this? I guess the solution will be really easy...


I am running standard raspbian on Raspberry Pi-3.  pi@raspberrypi:~ $ cat /etc/os-release PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)" NAME="Raspbian GNU/Linux" VERSION_ID="9" VERSION="9 (stretch)" ID=raspbian ID_LIKE=debian HOME_URL="http://www.raspbian.org/" SUPPORT_URL="http://www.raspbian.org/RaspbianForums" BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"   I want to load dvb-core.ko but it fails with an error saying that this module is not under /lib/modules/4.14.79-v7+/ path, but it actually is under that path.  pi@raspberrypi:~ $ uname -r 4.14.79-v7+ pi@raspberrypi:~ $ ls /lib/modules/4.14.79-v7+/kernel/drivers/media/dvb-core/dvb-core.ko  /lib/modules/4.14.79-v7+/kernel/drivers/media/dvb-core/dvb-core.ko pi@raspberrypi:~ $ modprobe /lib/modules/4.14.79-v7+/kernel/drivers/media/dvb-core/dvb-core.ko  modprobe: FATAL: Module /lib/modules/4.14.79-v7+/kernel/drivers/media/dvb-core/dvb-core.ko not found in directory /lib/modules/4.14.79-v7+   No new message is displayed in dmesg. I am confused by this false reporting. I am sure there is an explanation for this, but can't figure it out.

I'm looking for a few kernel modules to load i2c-dev and i2c-bcm2708. But the modprobe command returns:  sudo modprobe i2c-dev modprobe: module i2c-dev not found in modules.dep   How can I list all the available modules in the system? In which directory are they located?


We know that proton is positive, and electron is negative. But where does come notion of negativity and positivity? Does charge come from some specific particles, or they specific order?

Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they have with photons? And what about leptons, like muons and electrons? How do they get their -1 charge? And then, how do positrons and anti-muons get +1 charge? Same goes for quarks: how does up-antiquarks get -2/3 charge? Or I may want to formulate my question this way:  How does any elementary particle interact with the EM-Force to get an electric charge?


So, this a question from a Phd qualifying examination. Given the following Lagrangan $$L=\frac{1}{2}\dot{q}\text{sin}^2q,$$ what is the Hamiltonian for this system? So, finding the canonical momentum $p$ and then using $H=p\dot{q} -L$, I find that it is identically zero. Now, the answer 'Zero' was a choice in the choices of answers given but the correct answer is that the Hamiltonian is undefined. I'm not sure why this should be the answer, though this is a pretty  weird dynamical system. The Euler Lagrange equations just give an identity and the Hamiltonian equations also seem rather off. The Hamiltonian equations would are $$\dot{p}=\dot{q}=0. $$ I'm hoping someone shed some light on this, it seems that any random Lagrangian doesn't constitute a dynamical system, so what I should I be looking for?

$$L~=~ \frac{1}{2} \dot{q}  \sin^2{q} $$  Is it zero or not defined?


I'm trying to write I in the following style:   How do I do this?

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


I tried to shrink my Windows Bootcamp partition using third-party software which led to my Macintosh HD partition missing from startup options. Unfortunately I don't have a recent backup for the whole drive to restore from. If I try to reinstall macOS from scratch it doesn't see the partition either.    Disk utility sees it but it's greyed out and is being shown as Unmounted without the option to mount it back.    Is there a way to fix this without wiping out the whole drive and reinstalling everything from scratch?

Yesterday, I have tried to delete an Ubuntu partition. Since, my Mac (13", MBPro mid-2014) doesn't boot. Now, I boot on Mac OS copy with an USB. i follow different subject of this forum (like this : ), and my volume partition change from FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF to 48465300-0000-11AA-AA11-00306543ECAC. But I still can't boot to it...    Thank you very much !


I am creating a form for a model, one of the fields of the model is a ForeignKey. I want the options of the ForeignKey to be the ones related to that instance of the model. to make it clearer, here is some code: views.py def AddOrderDetail(request, pk):     Product = Products.objects.get(ProductID=pk)     order = Orders.objects.last()     locations = Product.productqtys_set.values_list('Sublocation', flat=True).distinct()      form = OrderDetailForm(request.POST or None)  forms.py class OrderDetailForm(forms.ModelForm):     class Meta:         model = OrderDetails         fields = (              ...              'Location',              ...            )  now I want the data retrieved from the query that I am performing in the view: locations = Product.productqtys_set.values_list('Sublocation', flat=True).distinct()  to be the data that the user can select from while selecting the location of the OrderDetail. Moreover, I have another problem. I want to initialize some fields, I tried using the initial={} while defining the form in view, as shown below: form = OrderDetailForm(request.POST or None,  initial={"ProductCode": Product, "OrderID": order, "Location": locations})  but when I do that I get the following error, 'OrderDetailForm' object has no attribute 'ProductCode'. I tried another way in the Function in the view.py file which is the following:     form.fields['ProductCode'].initial = Product     form.fields['OrderID'].initial = order  but sadly, I still get the same error 'OrderDetailForm' object has no attribute 'ProductCode'. Any help is appreciated. Thank You.

Say I have the following in my models.py:  class Company(models.Model):    name = ...  class Rate(models.Model):    company = models.ForeignKey(Company)    name = ...  class Client(models.Model):    name = ...    company = models.ForeignKey(Company)    base_rate = models.ForeignKey(Rate)   I.e. there are multiple Companies, each having a range of Rates and Clients.  Each Client should have a base Rate that is chosen from it's parent Company's Rates, not another Company's Rates.  When creating a form for adding a Client, I would like to remove the Company choices (as that has already been selected via an "Add Client" button on the Company page) and limit the Rate choices to that Company as well.  How do I go about this in Django 1.0?    My current forms.py file is just boilerplate at the moment:  from models import * from django.forms import ModelForm  class ClientForm(ModelForm):     class Meta:         model = Client   And the views.py is also basic:  from django.shortcuts import render_to_response, get_object_or_404 from models import * from forms import *  def addclient(request, company_id):     the_company = get_object_or_404(Company, id=company_id)      if request.POST:         form = ClientForm(request.POST)         if form.is_valid():             form.save()             return HttpResponseRedirect(the_company.get_clients_url())     else:         form = ClientForm()      return render_to_response('addclient.html', {'form': form, 'the_company':the_company})   In Django 0.96 I was able to hack this in by doing something like the following before rendering the template:  manipulator.fields[0].choices = [(r.id,r.name) for r in Rate.objects.filter(company_id=the_company.id)]    seems promising but I don't know how to pass in the_company.id and I'm not clear if that will work outside the Admin interface anyway.  Thanks.  (This seems like a pretty basic request but if I should redesign something I'm open to suggestions.)


Why are my strokes on Krita getting artifacts when I project them on this gun in Blender? P.s. It only happens with this part of the gun.

I'm designing this animal-type creature, and want to add a transparent .png image to its face with the face features (object has a subsurf). On the left is the image with the features, on the right is the part of the object where I want it to be.    I tried to import the image as a plane, but matching the shape of the plane with the face didn't work, and the lines of the face left shadows on the head, and could be seen as a different object from some angles (although it's the closest I've gotten yet). It looked like this:    So , I tried selecting the faces of the head that the features should go over, and create a new material for it. Unfortunately, since the .png is transparent, the result produced was this:    (where it's impossible to tell the transparency from a black background default color, and where I wouldn't know where to start to adjust size and position).  I also tried UV mapping, but then the whole object became black with the features repeated all over.   Is it something I have to go into Nodes for? I'm kind of stuck here. Creating a new material and applying it is simple, but applying a material that is an image is a bit more complex it seems... Ideally, I would reproduce the same technique for the adhesive bandage on its arm (seen on the right of image 1).