Proving that $\int_0^1 \frac{\arctan x}{x}\ln\left(\frac{1+x^2}{(1-x)^2}\right)dx=\frac{\pi^3}{16}$

The following integral was proposed by Cornel Ioan Valean and appeared as Problem $12054$ in the American Mathematical Monthly earlier this year.  Prove $$\int_0^1 \frac{\arctan x}{x}\ln\left(\frac{1+x^2}{(1-x)^2}\right)dx=\frac{\pi^3}{16}$$  I had small tries for it, such as writting: $$I=\int_0^1 \frac{\arctan x}{x}\ln\left(\frac{1+x^2}{(1-x)^2}\right)dx\overset{ x\to \tan \frac{x}{2}}=-\frac12 {\int_0^\frac{\pi}{2}\frac{x\ln(1-\sin x)}{\sin x} dx}$$ And with Feynman's trick we obtain: $$J(t)=\int_0^\frac{\pi}{2} \frac{x\ln(1-t\sin x)}{\sin x}dx\Rightarrow J'(t)=\int_0^\frac{\pi}{2} \frac{x}{1-t\sin x}dx$$ But I don't see a way to obtain a closed from for the above integral.  Also from  we have the following relation: $$\int_0^1 \frac{\arctan x \ln(1+x^2)}{x} dx =\frac23 \int_0^1 \frac{\arctan x \ln(1+x)}{x}dx$$ Thus we can rewrite the integral as: $$I=\frac23 \int_0^1 \frac{\arctan x \ln(1+x)}{x}dx -2\int_0^1 \frac{\arctan x \ln(1-x)}{x}dx$$  Another option might be to rewrite: $$\ln\left(\frac{1+x^2}{(1-x)^2}\right)= \ln\left(\frac{1+x}{1-x}\right)+\ln\left(\frac{1+x^2}{1-x^2}\right)$$ $$\Rightarrow I= \int_0^1 \frac{\arctan x}{x}\ln\left(\frac{1+x}{1-x}\right)dx+\int_0^1 \frac{\arctan x}{x}\ln\left(\frac{1+x^2}{1-x^2}\right)dx$$ And now to use the power expansion of the log functions to obtain: $$\small I=\sum_{n=0}^\infty \frac{2}{2n+1}\int_0^1 \frac{\arctan x}{x} \, \left(x^{2n+1}+x^{4n+2}\right)dx=\sum_{n=0}^\infty \frac{2}{2n+1}\int_0^1\int_0^1 \frac{\left(x^{2n+1}+x^{4n+2}\right)}{1+y^2x^2}dydx$$  This seems like an awesome integral and I would like to learn more so I am searching for more approaches. Would any of you who also already solved it and submitted the answer to the AMM or know how to solve this integral kindly share the solution here? Edit: In the meantime I found a nice solution by Roberto Tauraso  and another impressive approach due to Yaghoub Sharifi .


Why double does not return correct precision?

Below program returns 0.009999999999999998. My question is why it does not return .01.       double a = 0.02;     double b = 0.03;     double c = b - a;     System.out.println(c);   I know BigDecimal will return expected output but i want to understand By what logic  answer is 0.009999999999999998 in double ?


Unresolved external symbol when using external dll

I got unresolved external symbol error when trying to use a function from external dll! Here is the code from exported dll:  //MathFunc.h #pragma once  template <class T> class MyMathFuncs { public:     T Add(T a, T b); };  extern "C" {     MYAPI MyMathFuncs<int>* createInst(){         return new MyMathFuncs<int>;     } }  //MathFunc.cpp #include "MathFuncsDll.h" #include <stdexcept>  using namespace std;  template <class T> T MyMathFuncs<T>::Add(T a, T b) {     return a + b; }   After compiling this project, I got .dll and .lib files. After that, I created a new project and added .dll file to output directory and .lib file to linker->Input->Additional dependencies. Here is code in the new project:  //main.cpp #include <iostream> #include "MathFuncsDll.h"  using namespace std;  int main(){     MyMathFuncs<int> * pObj = createInst();     cout << pObj->Add(1, 1) << endl;      cin.get();     return 0; }   However, when I compile it causes an error:  Error   1   error LNK2001: unresolved external symbol "public: int __thiscall       MyMathFuncs<int>::Add(int,int)" (?Add@?$MyMathFuncs@H@@QAEHHH@Z)    N:\Play around Code\DllApplication\DllApplication\main.obj   Is it because I have imported the dll wrongly or what? I have checked all the project's settings in the new project which included additional includes and additional dependencies(for .lib).


How are Random Forests not sensitive to outliers?

I've read in a few sources, including , that Random Forests are not sensitive to outliers (in the way that Logistic Regression and other ML methods are, for example).  However, two pieces of intuition tell me otherwise:   Whenever a decision tree is constructed, all of the points must be classified.  This means that even outliers will get classified, and hence will affect the decision trees where they were selected during boosting. Bootstrapping is a part of how a RandomForest does sub-sampling.  Bootstrapping is susceptible to outliers.   Is there any way to reconcile my intuition about its sensitivity to outliers, with sources that disagree?


How can a vector have both contra-variant and co-variant components?

I have read that contra-variant and co-variat vectors have different transformation properties , which distinguish them, yet at the same time I have read that a vector can have contra-variant and co-variant components. If a vector can have contra-variant and co-variant components, then isn't this vector both contra-variant and co-variant? But isn't this impossible?


Ubuntu 18.04 - Where can I find package lists to compare standard to minimal install?

I've been installing Ubuntu 18.04 and found out that there's this new option called Minimal Install. It says, "Web browser and basic utilities" will be installed, but I'm not given a specific list of removed programs.  I've searched the web and couldn't find the list . Can anyone help me with the list of missing programs in Ubuntu 18.04 minimal version compared to a normal installation?  Is there any official resource that tells the missing programs? I know there won't be programs like LibreOffice, games etc, but I need to know all programs that are removed from the minimal version.


The reason for saying "5 out of 10" instead of "1 of 2"?

I'm just being curious, i have seen on some places, statistical results where they give them in form of "10 of 100.000" or "5 of every 10".  I don't have any statistical knowledge over my personal experience/reading around. But basic maths tell me that such values could be simplified as any fraction we used to do:  10 of 100.000 -> 1 of 10.000 // 5 of every 10 -> 1 of every 2.  Is there any reason not to do it?  Edit:  The numbers come from, if i remember correctly:   10 of 100.000 people per year  with some bad reaction to medication 5 of every 10 people who actively smokes on ¿Spain?


On the Making of Decisions—Compound, Hyphen, or Space?

I'm responsible for most of the copy editing at my job.  While it goes pretty smoothly most of the time, there is one area that keeps creating a bit of cognitive dissonance for me:   decisionmaking decision-making decision making   I almost want to go German on it and make it into a compound word as in the first choice, but then I start thinking that a space would be more readable.  Then the hyphen appears out of nowhere as a less-than-satisfying compromise between the two.  No matter how I decide to go, I really haven't been able to find any peace on the matter.  Are there any official declarations from any of the major style guides on this matter?  For what it's worth contextually, the final customer for a lot of my writing is the US Federal Government.


I learned about Titanium Backup but I don't have a rooted device yet.   I'd still like to backup all my installed apps and their settings - will the default Google backup:    What does this backup exactly?  Sorry if this has been answered before but I really couldn't find it on quick search. So maybe it won't hurt to have my post here.  I see that my best option is adb () though... but I still don't know what the default Google backup does then... and why it's not enough...


Short story about humans losing a space war due to having SUPERIOR technology

In the story, an officer describes an ongoing war between humans and aliens.  The aliens have less advanced technology so they assume they will easily when.  However, the officer remises on how much of the new technology used in the war was unreliable and could not be produced in high numbers, and some even exploded and destroyed their own spaceships, leading to humanity losing a war of attrition.  The story was very short, 20 pages at most, and part of some collection/anthology, and released before the year 2010.


Can I make some text to load automatically whenever I open a file in Emacs?

I am a user of emacs but basically I use the basic commands. I do some competitive coding and for every problem that I solve in C++ I have to write  #include<iostream> #include<stdio.h> using namespace std; int main() {   return 0; }   before I start writing the solution. I was wondering that the mighty text Editor like Emacs must have some feature to pre include a text of string.


I have a model which have meshes that are not aligned at x axis. When I try to use automatic weight for connecting bones to meshes, I get "Bone heat weighting: failed to find solution for one or more bones" error. If I align bones to x axis, automatic heat weighting works but it is not suitable for my model.  I deleted all double vertices. And there are no open surface. Do you have any suggestion?


There is GTK in C/C++ and QT in C++. But, I don't want to use C/C++; is there a way to write GUI's in Linux using scripting languages? If so which scripting language and which bindings?  Note: I've intentially not mentioned a preferred scripting language because I don't want responses geared towards one language. Any scripting language will do.


Query regarding transit through Heathrow, London

Do I need a UK transit visa if my layover in Heathrow is for 2 hours? I will land at Terminal 5 and depart from Terminal 3. I won't leave the airport. My flight is from New Delhi to Vancouver. I have a connecting flight so collecting baggage isn't an issue. Please help me.  I am an Indian citizen and I will have a Canadian visa by then.


Installation error during linux firmware installation

while trying to install linux firmware this error came up.:  After this operation, 8,249 kB of additional disk space will be used. dpkg: error: parsing file '/var/lib/dpkg/status' near line 2093 package 'x11-xkb-utils':  field name `h��@' must be followed by colon E: Sub-process /usr/bin/dpkg returned an error code (2)   Any idea how to fix it?


I have some data on a drug where doctors are trying to find out based on collected data how many patients get heart disease because of a drug.  The output is the following:  95%CI 1.72(1.28-2.30) for the patients are taking this drug   95%CI 1.30(1.21-1.40) for the patients which are not taking the drug  Therefore we conclude that there is a 42% absolute increase for getting the heart disease compared to the no users. I think I’m right here?  Back to the CI-95%,, does this mean that if the study was repeated with another sample and the parameters being the same (age, sex, other diseases, other medications taken) that 95% out of the sample (let’s say a sample of 100 people which would then be 95 patients) would show the same amount of people getting the heart disease? Is this what the CI is all about? Because if we take a random sample but not with the same parameters values (age, sex, other diseases, other medications) we wouldn't get even close to the 95% we would have a 20% match or so..  In essence would the other sample yield the result of 95% of the patients being in the 1.28-2.30 interval and the other 5 % being outside of the interval?


How to create GPT partitioned bootable USB for uefi? I am on ubuntu and am trying to get back to windows

Basically I am trying to get back to windows so I can play league of legends on this pc. Any and all help is appreciated. I am not enjoying playing on ubuntu with playonlinux.


How much hard drive space do I need to install Windows 7 on my Mac via Boot Camp?

I have a Macbook Air and would like to install Windows 7 on it via Boot Camp. How much hard drive space should I make sure to have free before doing this?


Schrödinger's equation relation to quantum numbers

I tried searching for an answer everywhere but the equation is either solved from the physical point of view or they just cite it in chemistry textbooks without even showing how it is made to talk about orbitals.  What I was curious about, is how, specifically, quantum numbers describing an electron/ orbitals are related to the Schrödinger's equation.  Moreover I saw that there are different types of it, time dependent/time independent, which of these are used for atoms?  Ps : I don't have any deep understanding about differential equations.


The drag force on a spherical body according to  is given by  $$F = 6π\mu rv$$ Where $\mu$ is the dynamic viscosity of the fluid, $r$ is the radius of the spherical object, and $v$ is its velocity.  At low speeds, the drag force is directly proportional to the speed of the object. While at high speeds, the  is proportional to the square of the speed of the spherical object:  $$F = \frac{1}{2}\rho v^2C_dA$$  Why does this happen?


Random dynamical system in layman's terms?

As of now, the formal definition of a random dynamical system is a bit over my head. And many of the papers and books on this subject are not exactly "introductory-friendly." I still have a lot of years to go before I fully understand this topic, or rather, fully understand the prerequisites for this topic. I was wondering if someone could provide me a definition of a random dynamical system in layman's terms. For example, how would you describe random dynamical systems to a group of high schoolers?


bluej: how to create object with Date type

How can I give my datamember date from the type Date a value? I added in my class the import java.util.* statement but I can't find a way to give it a value. It isn't a string like "12-11-2014" This is one of my first project with Java, so I don't have many experience. ;-)  Greetings Moleculation  import java.util.*;  public class Training { // data members (instance variables) private double distance;  // in km private double time;  // in seconden private String type; private Adres address; private Date date;   public Training(int distance, int time, String type, Adres address, Date date) {     // initialise data members (if necessary)     this.distance = distance;     this.time = time;     this.type = type;     this.address = address;     this.date = date; } // getters public double getDistance() {     return distance; } public double getTime() {     return time; } public String getType() {     return type; } public Date getDate() {     return date; } public Adres getAddress() {     return address; }  // setters  }


Accessing class members on a NULL pointer

I was experimenting with C++ and found the below code as very strange.   class Foo{ public:     virtual void say_virtual_hi(){         std::cout << "Virtual Hi";     }      void say_hi()     {         std::cout << "Hi";     } };  int main(int argc, char** argv) {     Foo* foo = 0;     foo->say_hi(); // works well     foo->say_virtual_hi(); // will crash the app     return 0; }   I know that the virtual method call crashes because it requires a vtable lookup and can only work with valid objects.   I have the following questions    How does the non virtual method say_hi work on a NULL pointer? Where does the object foo get allocated?   Any thoughts?


Proving that $\prod_{k=1}^{n}\tan\left(\frac{\pi k}{2n+1}\right)=\sqrt{2n+1}$ using geometry

I have to prove that the following holds. A hint to use complex numbers has been given. I have tried to make a start but not to any result.      $$\prod_{k=1}^{n}\tan\left(\frac{\pi k}{2n+1}\right)=\sqrt{2n+1}$$     My Attempt:  Let us consider $(2n+1)^{\text{th}}$ roots of unity, $z_k=\exp\left(\frac{2k\pi i}{2n+1}\right)$. We can rewrite the product in terms of $\arg(z_k)$ as $\prod_{k=1}^{n}\tan\left(\frac{1}{2}\arg(z_k)\right)$. Or equivalently so, if we consider $(4n+2)^{\text{th}}$ roots of unity, we get this product as $\prod_{k=1}^{n}\tan(\arg(\zeta _k))$, where $\zeta_k= \exp\left(\frac{2k\pi i}{4n+2}\right)$.     I know it can be proved by proving the expression for $\prod\sin(\frac{1}{2}\arg(z_k))$. But I was wondering, is there a way to use telescopic products or purely the geometry of the complex roots of unity to arrive at this


HMAC for encrypted authentication token: recommended iteration number

In the web application I use 10,000+ iterations for hashing passwords stored in database (random salt and all). Password-related operations are not frequent enough to create a noticeable performance hit. Signing authentication tokens is a different story. This happens on every token renewal which may happen on every request but in practice is configured to happen at least every X seconds. I cannot find any recommendation as to the number of iterations for generating HMAC for encrypted payload such as the token. What are the risks of using a very low number, let's say 10? I use 24 byte salts.


Can we have a feature to shorten answers?

Some questions solicit, by their nature, have many answers. For example  or . Could we have a feature to hide comments, and shorten long answers (to perhaps their first line or so), so you can browse through many answers quickly?


How did Isildur possess the power to deny the Oathbreakers the Gift of Man?

When the Oathbreakers did not come to Isildur's aid as they had sworn to do, Isildur cursed them to be bound to Middle-Earth, unable to leave even after death until they fulfil their oaths to his line.  The Gift of Man is Illuvatar's blessing to grant to all mankind, good or evil. How is Isildur able to deny Illuvatar's gift to the Oathbreakers simply because of some earthly oath made to a royal Númenorean who possesses no divine power?


"define:" oneboxing selects completely bogus data

I found this weird word, "burke", and decided to check it out. It turned out it was an alternative spelling of "berk". This is what define: berk in chat expanded to:    So, according to that, "berk" as a noun can mean "a fool, prat, twit", or "berk", or "berk", or "berk". Wow, who would have thought "berk" might mean berk. Three times, just to be sure.  That got me really curious so I checked the wiktionary page directly. It shows three meanings for "berk": the same as meaning #1 that was oneboxed, plus two others that are not at all simply stated as "berk".  Further down from there we can find the other three "berks". Number three, for instance, is easy to trace since "indefinite plural berkë" seems quite greppable. And it turns out that it's Albanian.


My connection to mysql works but no any query

I'm having a bit of a weird problem. I'm trying to read data of my database, the connection works but the instruction doesn't.  I try with code that should work, query("show tables"); but this also doesn't show anything.  Application is another php in which I make the connection and configuration with the database.  use Aplication as App;  class Company {  public static function login($username, $password) {        $app = App::getSingleton();       $conn = $app->conexionBd();  // Check connection        if ($conn->connect_error) {           die("Connection failed: " . $conn->connect_error);         } echo "Connected successfully";        $query = sprintf("SELECT * FROM company E WHERE E.Name= %s", $conn->real_escape_string($username));        $rs = $conn->query($query);          if ($rs)       {          $row = $rs->fetch_assoc();         $c = new Company($row['id'], $row['Name'],$row['Password']);         $rs->free();          return $c;       }       return false;   } }   What is wrong?  Thanks in advance!


Calculating the Commutation Relation of the Generators of $SO(n)$

I'm working through problems in the book Einstein Gravity in a Nutshell by Zee, and I'm stuck on one of the harder problems. The problem is  Calculate $[J_{(mn)}, J_{(pq)}]$.  We are given that $[J_{(mn)}, J_{(pq)}] = i(\delta_{mp}J_{(np)} + \delta_{nq}J_{(mp)} - \delta_{np}J_{(mq)} - \delta_{mq}J_{(np)})$, and that $J^{ij}_{(mn)} = -i(\delta^{mi}\delta^{nj} - \delta^{mj}\delta^{ni})$.  I started off writing the commutator definition: $[J_{(mn)}, J_{(pq)}] = J_{(mn)}J_{(pq)} - J_{(pq)}J_{(mn)}$.   I'm rather new to indices and I keep getting stuck on how to write the above equation in index notation. I'm also a little confused on how to move between the $\delta_{ij}$ and $\delta^{ij}$ in the problem. Is there a trick I'm missing or is this just a problem involving a lot of algebra?  I see that there is another question here that is very similar, although I think my question is more about doing the algebra with the indices. This might be the wrong place to ask such a question, though.


PhD application question: "Why do you want to join my research group?"

Whenever somebody asks me "why are you interested in joining my research group", I find myself helpless. What are the usual points or aspects I should talk about in reply of this question?


Querying AuthSession with IsCurrent = TRUE only shows my user

While we may not be leading the pack in Salesforce adoption, I'm quite sure that a number of our 400 users are still logged in as If I look at session management in setup, there are plenty of UI sessions that are still valid.  But if I query select users.name from authsession where iscurrent = true as suggested by  it only returns my user.  The response clearly states that this should return all users.     This will give you a de-duplicated list of all the users with current sessions by name. You can also select any of the other usual User fields.   I have tried in dev console and via anonymous apex.  I am a system administrator.  Does this look like a bug, or is there something I am missing here?  FWIW my org is quite old.   Screenshots below  Dev Console Query Output   UI Sessions in Session Management (filtered for parentId = blank)


Some people have discussed in specific meta of site but I am asking here the center of every site.   I have seen a question which has good content but got down vote without any reason and one got up vote which is not closed by moderators. Or moderators are doing wrong, or maybe voters are doing wrong. If person doesn't like a content personally and voting it down or a person think that this content is good for community and given up vote.  What is the exact role of voting


Is there any difference between selected cities select cities?

Since a long time ago, I used to write selected instead of select because I thought select is just a verb, not adjective. But recently I came to know it's adjective, because I saw phrases like "select cities/users/phones" etc. Earlier, for the same phrase, I would write "selected cities/users/phones". I felt it natural and it was like a belief that I thought it is the right thing and I never really paid attention to it. For example, I would write: This game is available for selected users/cities. (My subconscious mind makes me feel both give same feeling and meaning) Now, I'm sure "select users/cities/etc." make sense and is absolutely right, but also I wonder if I could use "selected" too for the same purpose (in other words, could they be used as synonym phrases)? Or is it totally wrong use?


Tex4ht, biblatex and biber: what is proper processing?

How to run htlatex with biblatex bibliography included? That's the simplest example:  \documentclass{article}  \usepackage{biblatex} \addbibresource{libr.bib} \begin{document}  Text.\cite{dickens1881great}  \printbibliography \end{document}   I run in that way:  latex main biber main htlatex main   At the last stage htlatex asks about "Undefined control sequence":  \blx@begunit ...penalty \@M \hskip -\blx@unitmark                                                \relax \hskip \blx@unitmar... l.7 Text.\cite{dickens1881great}   And there's a lot of such errors in log file, but htlatex allows to skip them. Also, the html are not so good. Lack of punctuation, formatting:
C.  DickensGreat ExpectationsPenguin  English  librarypt.  1Dent1881url:     http://books.google.com/books?id=fhUXAAAAYAAJ.   Is it the best result possible or I did something wrong?


Detecting collision of two sprites that can rotate

I have a problem with collision detection in a 2D Java game.  Normally, what I would do is create a getBounds() method for an object that can collide with other objects. This method would return a new Rectangle(x,y,width,height), where x and y are the coordinates for the top-left corner of the sprite, and width and height are the width and height of the sprite.  But in the game I'm currently working on, there is a "tank" controlled by the user. The sprite of this tank rotates as long as the player holds one of the left or right arrow buttons. In other words, it can rotate to any angle. The tank's sprite is a rectangle.  So I can't simply do what I always do in this case.  How can I detect collision with this kind of sprite? Thanks


SciFi story involving wormhole and insanity

I think it was a short story or novella. A wormhole or some other portal is discovered and all attempts at automated study of what is on the other side fail - all recordings come back blank. They send people, but they come back insane so they have people trained as councilors to gently bring them back to reality. Also tied with my memories of this story is the concept of flowers - like maybe in the name or figures in the story.


ubuntu 14.0.4 64bit keeps freezing - NOT A DUPLICATE

I've just installed 14.0.4 on a new system and I've noticed that my computer will freeze at least 5 times in a work day, where I can move the mouse around, but i can't actually click on anything and my keyboard doesn't work either.  The only thing i can do is push the power button and restart the computer.   Just wondering what the best way to start troubleshooting this would be? I was thinking about checking for and installing any updates to 14.0.4 but i don't want it to affect certain packages like mongoDB or perl etc. I'm still trying to read up on how to selectively update... but if you have any suggestions for me, I'd appreciate it  I've read  but that doesn't seem to apply...   doesn't apply either. I've tried changing out my keyboard and my mouse.   I think it's related to having multiple monitors because when the system "freezes" I can still move the mouse, but it won't span across both monitors.  It gets "stuck" inside one... the keyboard still works... because I can shell out to a command prompt and restart the desktop.  But so far, I haven't figured out how to resolve it.  The  system correct detects that I have two 23" Samsungs... but other than that I'm not sure how to check if I have the right driver etc.  Thanks.


Let $f$ a continous function defined in the interval $[0,1]$. Assuming: $\forall x \in [0,1]:f(x) > x$ Prove: $\forall x \in [0,1]:f(x) > x + \varepsilon $  I tried to use  and did some Algebra tricks but it didn't bring me to a safe shore :)    What do you suggest? Thanks!


Why process substitution is faster than pipe in this case?

I am wondering why     ls -1 |  while read file; do       echo $file; tail -n 100 $file > >(sleep 1 && cat > $file) done     is faster than   ls -1 |  while read file; do      echo $file; tail -n 100 $file | (sleep 1 && cat > $file) done      ?    If there are 100 files in a directory then:    the second command takes almost 100 seconds to process  the first command is processed almost immediately.


What would be the best way to process a complex xml file in java?  Something like this:  <company> <owner>    <ownername></ownername>    <ownerage></ownerage> </owner>  <cars>    <car>       <carname></carname>       <engines></engine>        <user>           <name></name>           <age></age>           <address></address>        </user>    </car> </cars> </company>   What would be the best way to extract car or user?


How come ""mathematically"" that lasso shrinks the coefficient towards zero whereas ridge does not?


Equation is not numbering section and subsection

I am currently writing protocolls with latex. I want to numerate my equations like this: (1.1), (2.3) and so on, but it´s only numbering from (1) to (n) without remarking the sections. My preamble is, but with it its not working how i want: \documentclass[a4paper, 12pt]{scrartcl} \usepackage[ngerman]{babel} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{lmodern} \usepackage{subfiles} %\usepackage{enumitem} \usepackage{enumerate} \usepackage{amsmath,amssymb,amsfonts,amsthm,mathtools} \usepackage{graphicx} \usepackage{tabularx} \usepackage{color} \usepackage{colortbl} \definecolor{softgreen}{rgb}{.6,.98,.6} \usepackage{parskip} %Deaktiviert Absatzeinrückung \usepackage{tikz} \usepackage{multirow} \usepackage{hyperref} %Anklicken von Referenzen ermöglichen \usepackage[a4paper, includefoot, left=24mm, right=24mm, top=15mm, bottom=15mm]{geometry} \usepackage{cleveref} %Referenzieren ermöglichen \usepackage{chemformula} \graphicspath{{Grafiken/}} %\usepackage{uhrzeit}     \begin{document}   \section{Theoretische Grundlagen}  \begin{equation} 2 + 3 = 5 \end{equation}        \end{document}


I'm trying to fix the kerning around the quote with a feature file. I looked at several answer and tried this :  \documentclass[12pt]{article} \usepackage[french]{babel} \usepackage{filecontents,fontspec,microtype} \begin{filecontents*}{minion.fea}    languagesystem DFLT dflt;    languagesystem latn dflt;  feature kern {   pos  \quoteright \a 40;   pos \quoteright \eacute 10;   pos \quoteright \o 10;   pos \quoteright \e 8000;  } kern; \end{filecontents*} \setmainfont{MinionPro-Regular}[   FeatureFile={minion.fea},Path=fonts/] \frenchspacing \begin{document} l’étranger  d’accord  d’ores et déjà  L'e \end{document}   It doesn't change the kerning    it's particulary bad with a "L". Any tips ?  I'm using Miktex 2.9  Thank you   Edit: Using the suggestion in comment  \documentclass[12pt]{article} \usepackage[french]{babel} \usepackage{filecontents,fontspec,microtype} \directlua{ fonts.handlers.otf.addfeature { name = "ktest", { type = "kern", data = { ["quoteright"] = { ["e"] =  50,                    ["a"] =  50,                    ["eacute"] =  50,                    ["o"] =  50, }, } }, "extra kerns" } } \setmainfont{MinionPro-Regular}[   RawFeature=+ktest,   Path=fonts/] \frenchspacing \begin{document} l’étranger  d’accord  d’ores et déjà  L'e \end{document}


Continued use of the same dripping for frying - is it advisable?

I fry lamb chops and leave the dripping in the pan where it solidifies. Next time I cook something, the lamb dripping imparts extra flavour. I have heard that some people just wipe a frying pan instead of washing the grease off. I don't even wipe the pan - I let it build up. My reasoning is that (a) dripping doesn't go off and (b) any germs/bacteria would be killed by the heat of frying. Note: I leave the pan covered by a lid when not in use. Is there any reason that I shouldn't continue with this practice?


Is it possible to install an newer version of android for an old android device?

I've got a phone with Android 4.2.2 Jelly Bean installed on it, and it doesn't have a 'Software update' button. Is it possible at all to somehow install a newer version of Android on this device?  I also looked at a possibility to install CyanogenMod on this phone, but it doesn't have my phone in the list on . The model is the Lenovo A830, so it's not a conventional phone. Is it possible to install some kind of 'generic' version of Android on it?  Alternatively, can I install a mod that uses a more recent Android version?


Can a Canadian Travel to the USA twice, less than 180 days each time?

I plan to travel to the USA for less than 180 days in 2019. I will return to Canada for Christmas and New Years, then return to the USA for approx 4 months and for sure less than 180 days.  Can I do this? I've seen online 180 per calendar year (which would make this plan ok) and in other places per 12 month rolling period (which would make it not ok.)


Does anyone have style sheets for the shapefile extracts of OpenStreetMap? The layers which are downloaded "Lines" "Multilinestrings" "Points" "Multipolygons" all have attributes associated to them and someone must have dedicated some time towards creating very pretty styles, especially when being open source.  relating to this question direct me to sites with .qml style files although they apply to layers which do not correspond to the more modern shapefiles downloaded from OSM.     I ended up just styling it under my own steam, check it out!


I am trying to auto mount a remote resource through sshfs but is not working for me. I have read all of , ,  and  before ask to see if I can get the solution for my issue but it didn't work.  So here is what I have done so far:   Added the following line to /etc/fstab:  <username>@remote_host_ip_address:remote_path host_path fuse.sshfs delay_connect,_netdev,user,idmap=user,transform_symlinks,identityfile=/home/<username>/.ssh/id_rsa,allow_other,default_permissions,uid=1000,gid=1000 0 0  I have ssh into the remote host once so it gets added to the /home/<username>/.ssh/know_hosts file. I have checked after and the remote host is there I have run the command sudo mount -a    When I change directory and check the local path something goes wrong since I can not cd into it and it looks like:    What I am doing wrong here? What I am missing?


We define  $$a_{n+1}=\frac{1}{1+a_n}, a_0=c> 0$$   I stumbled across that sequence and Mathematica gives me that it converges against $\frac{1}{2} \left(\sqrt{5}-1\right)$ which doesn't even depend on $a_0$. Normally I show that sequences converge by seeing that they are monotonic and then the limit can be easily found by setting $a_n=a_{n+1}$, but this one seems to be alternating. Also by checking OEIS I noticed that $a_n=1/g(n)$ where $g(n)$ gives the $n+1$'th .  I would be glad if someone can show me how to show that such sequences converge and how to find the limit, also maybe this is a well known sequence, as it has a quite simple form, too bad that google is very bad for looking for sequences and OEIS doesn't mention anything.


Is there an analytic function $f$ on $B(0,1)$ the open ball with radius 1 such that $f(1/n)=e^{-n}$ for $n=2,3,4,...$?

Is there an analytic function $f$ on $B(0,1)\subset\mathbb{C}$ such that $f(1/n)=e^{-n}$ for $n=2,3,4,...$? I know the following doesn't work:  Let $g(z)=\exp(-1/z)$. Then, $f=g$ on a sequence with a limit point in $B(0,1)$ and so $f=g$ on $B(0,1)$. Since $g$ is not $\mathbb{C}$-differentiable at $0$, neither is $f$ and so such a function cannot exist.  This is not the solution because you cannot use the identity principle with a non analytic function like $\exp(-1/z)$ is not analytic at $z=0$. Any help using the identity principle another way?


This rather inelegant method takes an input array of objects and outputs a string result, which is the result of ToString() for each element, space separated.   string Format(object[] args) {    var res = string.Empty;    foreach (var o in args)    {       res += o.ToString();       if (o != args.Last())          res += " ";    } }   Surely there is a C# method hidden somewhere to do this type of operation, or if not, a more elegant way to write it using Linq? Another concern with how I have written this method is the garbage generation by building the string incrementally.


Determining beta distribution parameters $\alpha$ and $\beta$ from two arbitrary points (quantiles)

Suppose I have two points $(p_1,x_1)$ and $(p_2,x_2)$ where $p_i$ is a probability on the beta CDF and $x_i$ is a value on that same CDF.  How would I go about determining the beta distribution shape parameters $\alpha$ and $\beta$ with only these two points?  To clarify, I'm assuming I already know the lower and upper bounds of the distribution L and U.


"crossfade between 2 videos using ffmpeg" without losing audio

""  In the above link I found a way to add fade between 2 videos, but losing the audio. How can I do the same without lose the audio?  This is the command line I'm currently using, which is working very well, just losing the audio:  ffmpeg -i in0.mp4 -i in1.mp4 -filter_complex "[0]fade=t=out:st=0:d=1:alpha=1,setpts=PTS-STARTPTS[va0];[1]fade=t=in:st=0:d=1:alpha=1,setpts=PTS-STARTPTS/TB[va1];[va0][va1]overlay[outv]" -map [outv] -crf 10 out.mp4


Clipping polygon layer according to DEM elevation using QGIS?

I have a polygon layer on top of a DEM.  Is there a way to clip the polygon layer according to elevation, ie the clipped result being only those areas of the polygon layer between x and y altitude?  The result needs to be a vector layer.


I try to run some commands at boot. I learned that one should add them in the /etc/rc.local file (on ubuntu 12.04 LTS).  Here my file:  #!/bin/sh -e # # rc.local # # This script is executed at the end of each multiuser runlevel. # Make sure that the script will "exit 0" on success or any other # value on error. # # In order to enable or disable this script just change the execution # bits. # # By default this script does nothing.  /usr/bin/touch /tmp/test.rc.local  exit 0   But after reboot no file was created in /tmp/ which indicates to me that rc.local was never executed.  Note: rc.local as (in my opinion) the right permission:  > ls -l rc.local  -rwxr-xr-x 1 root root 446 Sep  3 15:55 rc.local


In Prometheus, does David dislike humans?

In the movie, does it ever state that David has disdain for humans in general?  Is there any confirmation of his opinion of his fellow crewmates?


I'm having this question in my homework assignment in Linear Algebra and diffrential equation class, and trying to find the general solution for this second ODE.  $$y''y^3 = 1$$  Using substitution I said $p = y'$ and $p' = y''  \rightarrow  \frac{dp}{dx}= \frac{dp}{dy} \times \frac{dy}{dx}$  Then we get $y^3 \frac{dp}{dx}$ now what's the next step should I integrate or differentiate the equation? What's the trick on these type of ODEs?  Thanks in advance!


The differences between libpam-ldap and libpam-ldapd, included packages and modules?

May I ask what's the differences between libpam-ldap and libpam-ldapd when it comes to included packages and modules?  As i understand is nss-pam-ldapd the project of libpam-ldapd, which is an improvement of nss_ldap. So, is nss_ldap the same as libpam-ldap or is it just the NSS which is included in the libpam-ldap package which as been improved, and everything else is the same?  Trying to write a report, but cannot understand what's included in those two packages, especially in libpam-ldap.


can search an unordered list of length $N$ in time $\sqrt{N}$  on a quantum computer. Applied to cryptography, this means that it can recover n-bit keys and find preimages for n-bit hashes with a cost of $2^{n/2}$. But the basic version of Grover's algorithm is sequential. Each iteration uses the output of the previous iteration as input. I don't see an obvious way to parallelize the algorithm. Reducing the number of iterations significantly reduces the success probability more than linearly. If the algorithm is inherently sequential, building a bigger computer won't speed up the attack, limiting its impact. $2^{80}$ sequential cipher invocations looks pretty hard to achieve to me. On the other hand, $2^{80}$ parallel cipher invocations is already on the edge of feasibility today using classical computers. Assume an attacker using a quantum computer is limited to $T$ timesteps with $T<\sqrt{N}$, so they can't run Grover's algorithm with the optimum number of sequential steps. What's the cost for finding a preimage/recovering a key? What is the average cost per-break if they have multiple targets?


Notification on long-running query or deadlock in SQL Server 2008 R2?

I'd like to know if there is a way to send a notification on deadlock? If so what queries would be required. I understand that SQL Server takes care of deadlocks, I simply would like information on the queries involved.  I found the following to determine long-running queries:  SELECT      creation_time     ,last_execution_time     ,total_physical_reads     ,total_logical_reads     ,total_logical_writes     , execution_count     , total_worker_time     , total_elapsed_time     , total_elapsed_time / execution_count avg_elapsed_time     ,SUBSTRING(st.text, (qs.statement_start_offset/2) + 1,     ((CASE statement_end_offset         WHEN -1 THEN DATALENGTH(st.text)         ELSE qs.statement_end_offset END     - qs.statement_start_offset)/2) + 1) AS statement_text FROM sys.dm_exec_query_stats AS qs     CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st   where total_elapsed_time >= 300000000 --5 min ORDER BY total_elapsed_time / execution_count DESC;    I'd like to know if the above is the right way to go, or is there a better way to determine if any query takes longer than a specific interval say 5 min as shown?  Thanks


How do I Hide a post from Google results when I type my url?

Right now I'm confused & urgently need some help. My website content is continuously copied by a new website. Sorry but I can't mention my site & the other site.  I searched in Google, how to hide my recent post & I found WP hide post plugin, which worked perfectly on my website & all my recent posts are hidden from the home page, in the search results of my website in tags & everywhere else. The problem is that my content is still copied by the other site.  Then, I came upon the Google results & when it typed in my url, all my recent posts are shown on the first & second page of Google results. Is there any option that the search results will not show my recent posts when I type in my URL?  I would also like to mention one more thing that I also hide the date & time from the post. But still all my recent posts are shown in the Google results, and from the clone.


I have been wondering recently if there are any Pronunciation "Easter Eggs" in the English language (not unlike how "Ghoti" is pronounced like "Fish"). Are there any others? Please provide phonetic proof if you claim so.


I was doing a very simple search:  grep -R Milledgeville ~/Documents   And after some time this error appeared:  grep: memory exhausted   How can I avoid this?  I have 10GB of RAM on my system and few applications running, so I am really surprised a simple grep runs out of memory. ~/Documents is about 100GB and contains all kinds of files.  grep -RI might not have this problem, but I want to search in binary files too.


How much Valyrian steel is there that is unused for link making and why aren't people making weapons out of it?

I was reading  that stated Maesters can have Valyrian steel links:     Valyrian Steel links (for the study of Magic + the Occult) are exceedingly rare and held by less than one Maester in a hundred. Ironically, they aren't seen as especially prestigious but rather viewed with suspicion.   This made me wonder how much Valyrian steel there is lying around for Maesters to be adding them to their chains. It seems like such  resource like this would be used for crafting weapons not being kept as ingots ready for Maesters to make links.  Indeed the Wiki I linked above claims:     the amount of Valyrian steel in the world is finite and extremely rare   How much of his extremely rare resource is being kept in reserve for link making and why hasn't it been used for more useful stuff like making weapons?


Transferring from Domestic terminal T1B to International terminal T2 with luggage - Chhatrapati Shivaji International Airport

We will be arriving at the domestic Terminal 1B and need to transfer to the International Terminal 2.  We are a family of 4 with 8 pieces of checked luggage and four carry-on bags. Will there be big enough vans available?   We will be arriving around 4:30pm and our connecting international flight is at 10:20 PM. I haven't traveled through Mumbai airport in the last 10 yrs, so not sure about the current amenities.


Sense Automotive 12V Circuit from 3.3V microcontroller safely

I want to sense a circuit state in an Automotive circuit (12V nominal) from a 3.3V microcontroller (MSP430Gxxxx). The circuit is normally 12V (or VBat) until either the Wireless ECU or a Door Key grounds the line, triggering an event. How can I safely (in terms of not frying the MCU or affecting the state of the line) sense this?  From the Manufacturer description, this seems to be a simple Open Collector system, it is not a power circuit, so I don't know how much current can be sourced.    I would tap into junction J6.  As this is automotive, current consumption is a concern as well. My MCU will be set up to interrupt on a falling edge trigger, and asleep unless that happens.


Tips and resources for beginning designers

Thanks to the internet, graphic design and programming are becoming increasingly overlapping fields.   As a programmer, I constantly find myself needing basic knowledge of Graphic Design, but have trouble locating thorough yet concise graphic design learning resources, and instead usually find bits and pieces of knowledge applicable to the task at hand.  Can you guys offer some tips or recommend some good books, tutorials, blogs, and websites which provide a beginner level overview of web design that have been, in your experience, effective and high quality learning materials. I'm not looking for tips on how to use image editing tools, but assuming a basic grasp of those, which resources and advice will best help a new designer create professional looking designs?


I'm quite new to photography in general I've mainly in the past tried to get killer camera phone shots, now the missis has just got me a used d3200 for my birthday, it's body only so has no lens I'm looking at picking up a cheap 18-55mm vr for it to be going on with and keeping my eye out for bargains, but also I'm looking at some sort lenses for the olden film days any advice appreciated.  I've read that Sir lenses are obviously missing features like auto focus which I don't find a problem, metering and iso etc I would like to learn more about and I think an sir lens is a good way to go about it and they seem pretty cheap, my main question is will all nikon lenses fit (presuming their all F-mounts?)  thanks..


I'm using jquery and use a php file to display dynamic contents to different URLs. The php file takes the current url (referal) and it queries for respective content in the database:  $url =  $_SERVER['HTTP_REFERER'];   Here is the jquery:

    I know bots can fake url referal, but i'm not sure if it can get the content of my php file.  Anyone has experience with this? How to effectively hide that piece of content from bots?  Thank you very much.


I am able to log in with my user id but when I do I get only the desktop background. Unity apparently doesn't load.  I get no Launcher down the left side of my screen and no Panel across the top.  I get only a mouse arrow.  I'm able to bring up various windows by right-clicking my mouse or pressing a windows key on my keyboard.  I would think there would be a way to boot Unity, but I don't see anything in the windows that I'm able to open.  Also, I can't figure out anyway to get a command line.  There doesn't even seem to be a way from the screen to shut down the computer.  I have to use the button on my console.  I have just installed 14.04 in parallel to 10.04 in a dual boot arrangement with Windows 7.  I have Windows and Linux running on separate hard drives.  Things were working ok for the first few days after the install, but today this problem occurred.  Thank you for any help.  Bob Wetmore


Suppose, I have the following code:  \documentclass{article} \begin{document} We have totally 7 columns, describing the user: \begin{enumerate} \item ID --- users.name \item Forename --- users\_profiles.first\_name \item Surname --- users\_profiles.last\_name \item Email --- users.mail \item Primary Service --- services.name \item Start date --- FROM\_UNIXTIME(users.created) \item Employment Status --- users\_profiles.employment\_status \end{enumerate} \end{document}   Producing this document:    Is it possible to set the value 7 automatically, depending upon number of elements in the list? The problem is, that it resides before the list.


Intervals are connected and the only connected sets in $\mathbb{R}$

As the topic, prove that Intervals are connected and only connected  in $\mathbb{R}$. I know what is the definition of connected set. But not sure how to prove that.


This is the context:   1.3(10) = 13 13 - 10 = 3 |3| / 10 = 0.3   0.7(10) = 7 7 - 10 = -3 |-3| / 10 = 0.3   (1.3)(0.7) != 1   If the difference between both real numbers is 0.3, when multiplied together, why does the number < 1 hold greater influence over the product (i.e. 1.3*0.7 = 0.91) ?


Why do politicians all say "and" when they state a year number

"In two thousand AND eight blah blah blah until two thousand AND thirteen blah blah blah"  Is there some grammar rule that if you're stating a year you should say "and" within a number or is there a rule that in politics you should say "and" within a number?


I'm searching for a template which makes a document look like it's written with a real typewriter. Ideally, this means it's not only in mono-spaced font, but the hyphenation is adjusted accordingly. Also, some randomness would be nice (e.g. some characters more bold than others), so that it looks more natural.


How could be proved that a function that sends compacts into compacts and connected into connected implies f continuous ?  I’d appreciate even just the idea behind that (if the proof is too long)  Thanks


What happens if I activate WoW acc from old expansion code?

I'm interested in starting to play WoW coming from a started account, what happens if I buy and old WoW expansion such as Cataclysm, Wotlk, BC for super cheap and activate it? Will the account upgrade from starter to standard? And will I be able to level-up until bought the expansion level-cap or the 90 which is for the base WoW?


Machine Learning to improve Encryption algorithms

Can machine learning be used to improve encryption algorithms e.g.image encryption algorithms that use ECC ?


The NES classic Mega Man series uses a very specific scrolling technique that I'm having a hard time wrapping my head around implementing. Essentially, the level is divided into "screens" which are all the same size. Some of the screens smoothly scroll in to one another, creating the illusion of a wider fields of play. Some of the screens stop the camera from scrolling until the player has reached the edge of the screen, at which time a transition occurs and the next screen is shown. It is also possible for a single screen to have more than one transition, for example it has a ladder that goes up to one screen, but you could also walk forward to another screen.  How can these screen transitions be modeled?     Screen 0 is the starting screen, where the player starts. Screen 0-3 is horizontally smooth-scrolling and appears to the player as one continuous field of play. Since there is a transition between Screen 3 and it's neighboring screens 4 and 5, the camera will not advance past the right or top edges of Screen 3 unless the player moves to that respective edge and "pushes" through to the next screen. Once the player moves to either of the transition edges, user input is momentarily disabled and the camera transitions into the new area, after which user input is restored. The blue screen (Screen 5) has disabled horizontal scrolling so that only vertical transitions are possible. The green screen (Screen 6) has a vertical transition back to Screen 5 but also allows horizontal smooth-scrolling into Screen 7.   Edit: Implementing the transitions in terms of rooms lead me to this:    The small notches with an arrow are the regions in which a transition can occur. Each region has a "direction" and lies just outside of the room's visible area. As soon as the player hits a region, a transition will be started.


Fisher information for double exponential distribution

I am asked to find the Fisher information function for double exponential distribution with mean $\mu$ and variance 1.  Here's my approach: $l(\mu) = -\frac{1}{2}e^{|x-\mu|}$, so $\log l(\mu) = constant  + |x-\mu| $, $\frac{d\log l(\mu)}{d\mu} = -1$ if $x>\mu$ $\frac{d\log l(\mu)}{d\mu} = 1$ if $x<\mu$  Then $I(\mu) = Var(\frac{d\log l(\mu)}{d\mu}) = 0$  I suspect that this approach is wrong, please advise.


Implementing a sort of "tightened frenchspacing"

By default, (La)TeX adds extra space between sentences. The exact rules are in the TeXbook, a summary by TH. can be found . What follows is is my "executive summary":   After any period (or quotation/exclamation mark) that doesn't follow a capital letter, TeX adds a font's "extra space" to the "normal (interword) space". For Computer Modern 10pt, the normal space is 3.33pt and the extra space 1.11pt, resulting in an intersentence space of 4.44pt (+33% compared to the nomal space, assuming no stretch and shrink). A sentence end after a capital letter is indicated by the \@ command: Ann is learning the ABC\@. To denote that a period after a lowercase letter doesn't end a sentence, one may use \@ as well as an explicit space: Prof.\@ Higgins or Prof.\ Higgins.   Intersentence spacing may be brought in line with normal spacing by issuing the \frenchspacing command. (This is the standard setting for certain languages, e.g. the  (n)german option of the babel package.) With \frenchspacing enabled, there's no need to use the \@ command. One may revert to (La)TeX's default behavour by issuing \nonfrenchspacing.  So, there's the choice between extra intersentence spacing and uniform spacing. What is missing in my opinion is a third option I'll call "tightened frenchspacing": normal (interword) spacing between sentences and decreased spacing after non-sentence ending periods. To be somewhat more precise (while still ignoring stretch and shrink), I envision the following:   Adhering to a font's ratio between "normal space" and "normal space plus extra space" (3:4 for Computer Modern), the intersentence space is set to the normal space. The space after non-sentence ending periods equals the normal space multiplied by the above ratio (resulting in a space of 2.5pt for Computer Modern). As with \nonfrenchspacing in effect, the \@ command is used to denote cases of special punctuation.   How should such a "tightened frenchspacing" option be implemented?  EDIT: Thanks to Mico for providing what may well be a stepping stone to a solution. Here's another attempt at clarification:   Simply reducing the spacing after any period is not what I had in mind. There should be a (tangible) difference between end-of sentence spaces and spaces after non-sentence-ending periods (only that the latter should be reduced instead the former augmented). If adhering to a font's normal space/extra space ratio is not possible, a solution that adds a fixed (reduced) space (say, a thin space) after non-sentence-ending periods will be accepted. For compatibility reasons, I'd prefer a solution that works with the traditional use of \@ (i.e allows "tightened frenchspacing" for existing documents without the need to change the document body). Should it turn out that a different set of "special punctuation" macros is needed, I'll accept this as a solution.


Which browsers are officially supported, and what else do I need?

Which browsers are officially supported by Stack Exchange?  Also, what else is needed in order to use every feature of the site?


How to instantiate non-static inner class?

I have an inner class, which I want to instantiate from the static method of the parent class as follows:  public class MyClass {     public class B {         private int v;         B(int x) {             v = x;         }          public void pr() {             System.out.println(this.v);         }     }      public static void main(String args[]) {       int x=10;       int y=25;       int z=x+y;     B bb = new B(3);       System.out.println("Sum of x+y = " + z);     } }   It is throwing an error as follows:  error: non-static variable this cannot be referenced from a static context     B bb = new B(3);            ^ 1 error


Are there highly upvoted, accepted answers that quote just a website?

I recall, but not where, some highly upvoted, accepted answers somewhere that merely quoted text from a website, save one or two sentences sourcing the quote.  I ask as  on grounds of "plagiarism".


I've been using csvtools to read data from CSV files.  Is there any way to read data directly from a ODS file, to put the data into a LaTeX document?


Quick way to include a directory path when calling mv?

Often I will work out of the root of a rails directory where I find my self navigating the same path twice every time I would like to move a file:  mv app/views/layouts/application.html.erb app/views/layouts/application.html.haml   The haml is just one of may examples where I need to change the file name without modifying the directory it currently lives in and without changing directory.  Is there a way to achieve  this?


Why can we parameterize a null geodesic such that its velocity is four-momentum?

One principle in general relativity is that the wordlines of massless particles are null geodesics. It also seem to be a commonly stated fact (for instance see eq. (3.62) in Section 3.4 of Carroll's GR text) that one can parameterize the worldline of a massless particle as $x(\lambda)$ such that $$\frac{dx^{\mu}}{d\lambda} = p^{\mu}, \tag{1}$$ where $p^{\mu}$ is the four-momentum of the massless particle. To clarify what is meant by four-momentum, the energy of a particle with four-momentum $p$ as measured by an observer moving with four-velocity $U$ is $-p_\mu U^\mu$.  Now I understand why one could pick a parameterization that satisfies (1) at a particular point. But why must such a parameterization satisfy (1) globally?  The only argument I have is that such a parameterization always exists for the world-line of a particle with mass, and taking the limit to light speed suggests that such a parameterization should also hold for the world-lines of massless particles.  My question is: what are some other arguments for why the parameterization should exist?


Wireless Network Found, can't connect, repeated requests for authentication

I cannot connect to a wireless network, and am continually asked for the network password.  I have tried countless suggested solutions on the different locations I've already referred to. None of them have worked.  Details of my experience are as follows:  I have just recently installed Ubuntu 12.04.1 (32-bit). Ubuntu installed on my system seemingly fine, and I even formatted my hard drive during the process. It's as if it were a new desktop computer.  During the installation I was asked to connect to a Wireless Network. I have a USB Wireless Card connected which I have used to connect desktop PC's, laptops, and a Wii to the internet from approximately the same area of the house (thus the same distance from the Wireless Router). I chose my network, entered the correct password for it (I double checked; it's definitely the right password) and proceeded with the installation. Several times before the installation was complete, I was asked to authenticate the connection, and this seemed to do nothing each time. On the repeated screens the password was already entered in the appropriate box.  When Ubuntu booted up the first thing I was faced with (other than something about Language settings, or something) was another request for authentication. Again, the password was already there, so I clicked connect. It did not connect. Instead, I was once again faced with repeated requests every few minutes.  I went onto my laptop, which is connected to this network, checked the details of the network, and entered them manually into my Ubuntu PC (including the IPv4 and IPv6 information) but this didn't work either, so I set it back to finding the settings automatically. Note, also, that the "Connect automatically" and "Available to all users" boxes are checked, and have been unchecked & rechecked countless times. I have also tried having my User account connect automatically, and to need a password entered at the welcome screen.  Whilst I've been writing this, it has gone through a spat of connecting successfully to the network for less than a minute, before coming offline again, only to repeat the process. But it has now returned to prompting me for a password every couple of minutes.  This computer has already run on the Fedora OS, and had no trouble connecting to, and maintaining a connection. I also have a laptop running Windows 7 less than a metre away from this desktop PC, which is connected and has no trouble maintaining a connection at 50%-100% strength (fluctuating).  Therefore:   I know it's not the wireless card I know it's not the PC itself I know it's not the access point I know it's not the location of my PC or wireless card It is solely because of Ubuntu   Everything else has worked fine, but the moment Ubuntu was introduced into the equation, it has gone completely wrong. Honestly; I prefer Ubuntu as an OS to Fedora, but if I can't solve the problem it'll be straight back to Fedora that I'll have to go.  Can anyone help me at all?


How to change the boolean value of a global variable inside a function

start=True def funcA():    if(start):        #doSomething     else:        start=False   this leads 'starts' to  an unresolved reference  Is there a way to change 'start' to False inside funcA ?


Long lay over in Seoul. Do I need a visa as a Filipino citizen?

I'm a Filipino immigrant from USA about to visit home in December.  I have a 14-hour lay over in Seoul,  South Korea.  Do I need a visa to leave the airport to do a little sightseeing?


What is the "^" symbol for when declaring or defining a member?

I'm currently following a quick tutorial. And the XOR "^" symbol has cropped up in a place I've never seen it before. Exactly where the asterisk would be if I were declaring a pointer to an object.  See it in the code snippet below.  COpenGL(System::Windows::Forms::Form ^ parentForm,              GLsizei iWidth, GLsizei iHeight)     {         CreateParams^ cp = gcnew CreateParams;          // Set the position on the form         cp->X = 100;         cp->Y = 100;         cp->Height = iWidth;         cp->Width = iHeight;   Afterwards the object cp is dereferenced as if it were a pointer to an object of CreateParams type.  So....what does the ^ mean? Google has not been too friendly.


I recently tried many times to log into Area 51 with my Stack Exchange OpenID. Each time, I got this:    Then, I went to my OpenID account, and I saw this:    ...what is going on??  I have chrome, and extensions that block 3rd party cookies... is that the problem?


junit 4.10 how to get the test case name printed before the test starts running..  So here I want to print "sampleTest".  How do I do it in junit 4.10 ? Thank you in advance  class1: TestSuite all = new TestSuite(); all.addTestSuite(class2); all.run(result);  class2: public class profileTest extends TestCase() {   //I want to print the test cases name before the test actually starts executing      @Test     public void sampleTest1(){         //Some code here.     }      @Test     public void sampleTest2(){     //some more code here.     } }


Automatically add a vertical spacing in formula numbering

I have a document with several equations that fit the text width, so the tag is below the equation in those long formulas. I don't want to use splitting enviroments but in some cases, specially in cases environment with \frac{}{}, I would like more distance between the tag and the equation. I know it is possible to manually add this space with \raisetag command. Is it possible to automatically increment this vertical spacing only for those equations that fit the line width?  Thanks in advance.  \documentclass[a4paper]{article} \usepackage{amsmath} \begin{document} \begin{equation}  a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a  \begin{cases}   \frac{1}{2}\\   \frac{1}{3}  \end{cases} \end{equation} \end{document}


Which Stack Exchange website is for mobiles?

I know so many Stack Exchange sites, but I'm a bit confused about where to ask about problems we face in our cell phones. Or any type of any other electronic device.  I am facing so many problems with my phone. So I have so many questions about mobile phones. Please let me know if there is any forum related to mobile phones.


Is there any way to view all tag synonyms that I can vote on, with my tag scores?  I can't find anything in the main interface, but perhaps there's a data query I can't find?


Differentiate spoilers from empty block quotes

I have to admit, I didn't even know spoilers were supported until today, but really bugs me that spoilers just look like empty block quotes before you mouse over them.   Is this a spoiler or just a long empty block quote? I can't tell right away, so it would be really nice if there was some indication of which one it was so I didn't have to push my mouse all the way over to it. What can I say, I'm incredibly lazy.  vs.         I suppose the author should include something that says 'Spoilers below:', but it would be nice if there was some other indication of what it was.


Java program to ask user for basic input and to return a value

I am writing a Java program to decide how much a user has to pay for a delivery charge for a school project.  I have been advised the method that works out the cost has to be static.  When i de-bug my code the value of the price is never changing and i don't know why, please see my code below.  main method  package questionOne;  import java.util.Scanner; import questionOne.DeliveryMenu;  public class DeliveryMenuDemo {  public static void main(String[] args)     throws java.io.IOException {      String choice;      DeliveryMenu d = new DeliveryMenu();      System.out.println("Enter the type of Delivery service needed (Standard/Super/WowWee)?");      Scanner scanner = new Scanner(System.in);     choice = scanner.next();     d.setDeliveryCost(choice);     d.getPrice();   }   }  and class with other methods  package questionOne;  public class DeliveryMenu {  private static String delivery; private static int price=0;  public static int setDeliveryCost(String choice) {     if(delivery == "Standard") {         price = price + 22;     } else if (delivery == "Super") {         price = price + 44;     } else if (delivery == "wow-wee") {         price = price + 60;     }        return price; }  public String setDelivery(String s) {     return delivery=s; }  public void getPrice() {     System.out.println(price); }   }  price is never changing to the desired amount.


Finding a closed form for $\sum^{n}_{k=1} \frac{k}{(k+1)!} $

I'm finding a closed form to  $\sum^{n}_{k=1} \frac{k}{(k+1)!}  (n \leq 1) $ (in a environment of induction and recurrence)   I've been trying to solve it without success, can anybody help me (?)  The last thing I've tried to do is write the expression as a Non-Homogeneous Linear Recurrence:   $ f(1) = \frac{1}{2} $   but, actually I have no idea of how to attach it.   $ f(n+1) = f(n) + \frac{1}{(n+2)n!} $


Catalina is giving me 600% of CPU usage on accountsd

This is driving me nuts. Since I upgraded to Catalina (10.15.7), the accountsd process goes up to 680% of CPU usage:  The only thing that 'fixes' this, is logging out of iCloud, but then I loose access to my notes and contacts.


Can I cast instants in response to my opponent declaring blockers?

When my opponent declares blockers, I want to be able to kill a blocking creature (with something like ) while still doing combat damage to my opponent.  Is this possible?


How to prove that if $\sum_{n=0}^{\infty}a_n$ absolutely convergent $\Rightarrow \sum_{n=0}^{\infty}(a_n)^2$ convergent

I need to prove that  if $\sum_{n=0}^{\infty}a_n$ absolutely convergent $\Rightarrow \sum_{n=0}^{\infty}(a_n)^2$ convergent.  Do you have any idea haw can I prove it?  Thank you!


Get enitity ID after programatically creating one

I have a the following code:  // Create an Entity with wrapper   $node = entity_create('node', array('type' => 'person'));   $entity = entity_metadata_wrapper('node',  $node);    // Add a node title   $entity->title = $person['name'];    // Add the address information   $entity->field_person_address->thoroughfare = $person['address'];   $entity->field_person_address->locality = $person['city'];   $entity->field_person_address->administrative_area = $person['state'];   $entity->field_person_address->postal_code = $person['postalcode'];   $entity->field_person_address->country = $person['country'];    // Save the entity   $entity->save();   The data is saved in the DB perfeclty, but I need to get the entity ID of the new save node.   How do I do that?


How can I resolve an IP address to a hostname in Arch Linux?

What is the most concise way to resolve a hostname to a local IP address in Arch Linux?


Inconsistencies when calculating the remainder where 220 % 25 gives a remainder of 20 while 420 % 25 gives a remainder of 19?

As a part of the CS50 course we're tasked to create a program (in C) that calculates the least amount of coins ($0.25, $0.10, $0.05 and $0.01) from a value submitted by the user. My idea was to take the input value and multiply by 100 and use integers since the only value of interest is the number of coins and not the monetary value, hence I don't have to tinker with any decimals. The code is: #include <cs50.h> #include <stdio.h> #include <math.h>  int main(void) {     //If it's NOT a positive number, do this.     float n;     do     {         n = get_float("Change owed: \n");     }     while (n <= 0);      //Multiplying change owed with 100 to avoid having to deal with decimals.     int cash = n * 100;      //Calculating the number of quarters ($0.25).     int quarters = cash / 25;                           //How many full quarters per cash.     int quarters_rem = cash % 25;                       //The remainder after full amout of quarters in cash.     printf("Number of quarters: %i\n", quarters);       //Test how many quarters.     printf("Remainder: %i\n", quarters_rem);            //Test how much remainder.      //Calculating the number of dimes ($0.10).     int dimes = quarters_rem / 10;                      //How many full dimes from the remainder when all quarters are deducted.     int dimes_rem = round(quarters_rem % 10);           //The remainder after full amount of dimes in quarters_rem.     printf("Number of dimes: %i\n", dimes);             //Test how many dimes.     printf("Remainder: %i\n", dimes_rem);               //Test how much remainder.      //Calculating the number of nickels ($0.05).     int nickels = dimes_rem / 5;                        //How many full nickels from the remainder when all dimes are deducted.     int nickels_rem = round(dimes_rem % 5);             //The remainder after full amount of nickels in dimes_rem.     printf("Number of nickels: %i\n", nickels);         //Test how many nickels.     printf("Remainder: %i\n", nickels_rem);             //Test how much remainder.      //Calculating the number of cents ($0.01).     int cents = nickels_rem;                            //How many full cents from the remainder when all nickels are deducted.     printf("Number of cents: %i\n", cents);             //Test how many nickels.      //Prints the least number of coins to be returned.     int coins = quarters + dimes + nickels + cents;     printf("%i\n", coins); }  The thing is that when I run the code and enter 2.2, 6.2 or 8.2, the output gives me a remainder of 20 after calculating the quarters. 2.2 x 100 = 220 -> 25 x 8 = 200 which gives a remainder of 20, as expected. This is true for 2.2, 6.2, 8.2, 10.2, 12.2, 14.2 and so on. However, this is not! true if I enter 4.2! If I enter 4.2 I expect: 4.2 x 100 = 420 -> 25 x 16 = 400 which ought to give me a remainder of 20, but instead I get a remainder of 19? I don't understand why the remainder is 19 in this instance but 20 in the others?


What is the command I ran and now I have no ubuntu left...  When I which the computer on, the monitor comes on, it goes passed the grub screen, it does not show anything after that.  How do I fix this?


What happens when you try to charm or otherwise control a creature that has been Intellect Devoured?

If a creature has been taken over by an Intellect Devourer, what happens when a Charm Person, Suggestion, or other similar spell is cast on it? Can it even be targeted with such spells?


Why are my rendered images blurry... when I zoom in, its completely blurry. I render my images to see how they are looking so far, and I zoom in to see blurry results... when I zoom in on the final rendered image, it is also blurry. I tried changing the resolution, but it didn't help. You may not think this image is blurry, but it is trust me. Does anyone know how to help?


Right now to open a file and load the information in you have to go to "File->open->OK" to open up a file. I want to make it so that you can drag a file from a folder in explorer.exe ad drop it to the form and the program would automatically load the file I dragged and dropped. Any ideas?


Book based on a waterworld with a monstrous overlord

I read a book a while ago ( read many years, maybe a decade ago, it was at least 20 years old then) about a watery planet ruled over by a monstrous overlord sea monster thing.   The hero rallies some of the floating villages to fight the monster and they make iron weaponry out of iron from blood as far as I can remember.   Beyond this I can't remember much about the book, but I'm sure at least one other person out there must have read it.  Edit for more potential details: I think the village folk were reluctant to trust the hero, he was maybe a stranger to them and a lot of them didn't want to upset the status quo.    The iron weapons were maybe to pierce the hide? A harpoon seems familiar, something to trap him with the aid of nets.


SQL Query that returns only the data that ends in "_0"

I need a query that returns only the data that ends in "_0"  Like this register   0691445_8793_76126_109919_0046_AD0217_201907_0   I tried with this:  SELECT mykey FROM mytable WHERE mykey LIKE '%_0'   But also returns data that ends in 0, like this  0691445_8793_76126_109919_0046_AD0217_20190710   Thanks in advance


failure in making bootable win 10 64 bit with woeusb

Please help me to fix this issue:  Error: File "/media/woeusb_source_1544544327_15932/sources/install.wim" in source image has exceed the FAT32 Filesystem 4GiB Single File Size Limitation and cannot be installed. You must specify a different --target-filesystem. Refer: https://github.com/slacka/WoeUSB/wiki/Limitations#fat32-filesystem-4gib-single-file-size-limitation for more info. Unmounting and removing "/media/woeusb_source_1544544327_15932"... You may now safely detach the target device   I also formatted the pendrive in NTFS and the error persists.


Homomorphism from the alternating group $A_4$ to $\mathbb{Z}_3$

Well, my question is how to construct an explicit homomorphism from the alternating group $A_4$ onto $\mathbb{Z}_3$, since it is known that the quotient group $A_4/V\cong \mathbb{Z}_3$, $V$ being the Klein group, I would like to find such a homomorphism with kernel $V$.


How much does Plate Armor of Gleaming cost?

I know that 5e magic items are supposed to be very rare and not for sale, yet both the DMG and XGtE list magic item prices based on rarity. We're going to be doing a series of one-shots with the same characters and have been put on a very low initial budget for items (no items from background or class), but are allowed to buy magic items with this money.  Magic item cost in both the DMG and XGtE only references the rarity of a magic item. Unless I'm missing a rule somewhere, this has the strange consequence that a commonly enchanted plate armor (100 gp) is (a lot) cheaper than a non-enchanted plate armor (1500 gp).   Am I missing something? If I'm not missing something: is this a design oversight or has there been an official comment on this?


Why couldn't Ellie's experience be corroborated by simply re-using the machine?

I recently re-watched Contact for the first time since my childhood, and while I thoroughly enjoyed it, I realized that there was something I'd never understood: why couldn't they corroborate Ellie's account of her journey?  As far as I could tell, the pod fell harmlessly through the machine.  That is, it didn't break anything, and the machine wasn't destroyed.  I don't recall any dialogue about circuits being fried or the system shutting down, so presumably it wouldn't be hard to simply hoist the pod up and go again.  I imagine the energy draw was substantial on the local Japanese power grid, but given the amount of effort and money already invested in the machine, surely "Round 2" wasn't out of the question?  I mean, they almost certainly expected that this machine would get more than one good use out of it, anyway!  So given Ellie's vehement insistence that the machine had worked, the public nature of the controversy surrounding her testimony, and the government's (secret) findings that her device had recorded 18 hours of static, why wasn't it the obvious choice to have someone else suiting up the next day, ready to drop through the machine and corroborate her story?


Electromagnetic waves have a physical crest and trough as observed in microwaves and radio waves. I understand that is electromagnetic field vectors that wave, not the photon. But how do they wave? What does causes them to change direction?


ERROR: "token" parameter not in video info in youtube-dl

This error occurred when using youtube-dl:  [youtube] 1234567890A: Downloading webpage [youtube] 1234567890A: Downloading video info webpage ERROR: 1234567890A: "token" parameter not in video info for unknown reason;    please report this issue on https://yt-dl.org/bug.  Make sure you are using the latest version; type youtube-dl -U to update.    Be sure to call youtube-dl with the --verbose flag and include its complete output.    I tried to uninstall youtube-dl and reinstall it, but this error reoccurred.


Resampling / simulation methods: monte carlo, bootstrapping, jackknifing, cross-validation, randomization tests, and permutation tests

I am trying to understand difference between different  (Monte Carlo simulation, parametric bootstrapping, non-parametric bootstrapping, jackknifing, cross-validation, randomization tests, and permutation tests) and their implementation in my own context using R.  Say I have the following situation – I want to perform ANOVA with a Y variable (Yvar) and X variable (Xvar). Xvar is categorical. I am interested in the following things:  (1) Significance of p-values – false discovery rate  (2) effect size of Xvar levels    Yvar <- c(8,9,10,13,12, 14,18,12,8,9,   1,3,2,3,4) Xvar <- c(rep("A", 5),  rep("B", 5),    rep("C", 5)) mydf <- data.frame (Yvar, Xvar)   Could you gel me to explain the  sampling differences with explicit worked examples how these resampling method work?  Edits: Here are my attempts:  Bootstrap  10 bootstrap samples, sample number of samples with replacement, means that samples can be repeated     boot.samples <- list() for(i in 1:10) {    t.xvar <- Xvar[ sample(length(Xvar), length(Xvar), replace=TRUE) ]    t.yvar <- Yvar[ sample(length(Yvar), length(Yvar), replace=TRUE) ]    b.df <- data.frame (t.xvar, t.yvar)     boot.samples[[i]] <- b.df  } str(boot.samples)  boot.samples[1]   Permutation: 10 permutation samples, sample number of samples without replacement   permt.samples <- list()     for(i in 1:10) {        t.xvar <- Xvar[ sample(length(Xvar), length(Xvar), replace=FALSE) ]        t.yvar <- Yvar[ sample(length(Yvar), length(Yvar), replace=FALSE) ]        b.df <- data.frame (t.xvar, t.yvar)         permt.samples[[i]] <- b.df      }     str(permt.samples)     permt.samples[1]   Monte Caro Simulation     I am not sure about all above terms and whether my above edits are correct. I did find some information on  but I could not tame it to my situation.


I need to understand the relation between both these concepts with an example. I have an good understanding of Poisson distribution and it's applications. But I am having difficulties linking it to Poisson Process.


403 error on callout to service ran locally

I have a service I'm running in a docker container locally, listening in port 8000. The service is non http secured. I'm trying to send a GET request from my apex code to the service and getting an 403 error. The user has "API enabled", and the endpoint was added to the "Remote Sites". When I try sending the same request from postman or the browser, I reach the service and get the required response. This is my code: HttpRequest request = new HttpRequest(); request.setEndpoint('http://localhost:8000/ABRequest'); request.setMethod('GET');  Http http = new Http(); HttpResponse response = http.send(request); System.debug(response.getStatusCode());  Can anyone help me understand what I'm missing?


Selecting data from SQL Server with Accent Marks not working on PHP

For some reason I cant retrieve data from a query to a username with accent marks, but the same data retrieving works perfectly if the user has no accent marks.  This is the PHP query:  $query = "SELECT * FROM [dbo].[Users] WHERE User= 'Róger'"; $result = sqlsrv_query($conn, $query); $row = sqlsrv_fetch_array($result); $UserID = $row['ID']; echo "ID is: " . $UserID;   This is my result on website:  ID is:   This is what i get from var_dump($query);  "SELECT * FROM [dbo].[Users] WHERE User= 'Róger'"   Now, if we change $query from  $query = "SELECT * FROM [dbo].[Users] WHERE User= 'Róger'";   to  $query = "SELECT * FROM [dbo].[Users] WHERE User= 'Robert'";   Then it properly shows up the UserID.   Any ideas?


I'm cating a file, and the output is something like this:  Help me my friend Temptation Sorrow True Love Vanilla Sky I was here SOS ...   I'm trying to create directory of all of these lines.  What I have tried is:  mkdir `cat x.txt`   But the result is a mess! For instance, I was here will be split into three directories like I, was, and here. How can I fix this??  Thanks in advance.


Is the new statistics, number of people reached available in the data dump

I am interested to see how this new statistics motivate users to contribute. But in the data dump, this variable seems not to be in the data dump.


Finding expected value of Bernoulli random variables

Consider a sequence of $n$ Bernoulli trials with $P(\text{success})=p$. Let $X_i$ and $X_j$ be indicator variables of the number of "success" in $i$th and $j$th runs with $i<j$. In other words $X_i=1$ if the $ith$ trial is success and $0$ otherwise.. Given the total number of success was $m$. I am asked to compute the correlation coefficient for $X_i$ and $X_j$.  To compute the co-variance I will need to find $E(X_i)$ and $E(X_j)$ first. By definition $E(X_i)=p$ =$E(X_j)$. But how should I find E($X^2_i$)?


How do you set the path in a non-shell environment (KDE)?

I'd like to override one of the applications set in /usr/bin/. I have created an alternative with the same name in ~/bin/ which in in my PATH (as set both in .bashrc and in .profile).  When I start the application from the console, I get the expected result: my application is started instead of one from the distribution.  However, within KDE, when I do alt+F2 and type in the application name, the one in /usr/bin starts instead of the one in ~/bin/.   How do I set KDE so that ~/bin is recognized from everywhere in KDE.  I'll probably also have to edit the K-menu, although I am not sure how to do it with KDE4.


Where is the repeat button on a song for iOS 8.4 music app? Help!


Nginx won't listen to 443 even when netstat says it does

I installed SSL on a server, it all went well as I did on other servers before, but this is just not working, I check with sudo netstat -t -l -p -n  and I get this:  Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1062/sshd tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      2560/exim tcp        0      0 0.0.0.0:443             0.0.0.0:*               LISTEN      3129/nginx tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      3129/nginx   But when I try to access the website, the connection times out, now if I check with  for port 443, it will say the port is closed. Nginx -t returns no errors.   sudo iptables -L shows:  Chain INPUT (policy ACCEPT) target     prot opt source               destination  Chain FORWARD (policy ACCEPT) target     prot opt source               destination  Chain OUTPUT (policy ACCEPT) target     prot opt source               destination   sudo ufw status shows:  Status: inactive   My default.vhost file:  server {     listen       80 default_server;     # listen       [::]:80 default_server;     server_name  _;     root         /jet/app/www/website/public;      index index.php index.html index.htm;     autoindex on;      # Load configuration files for the default server block.     include /jet/etc/nginx/conf.d/*.inc;  #location / {            try_files $uri $uri/ /index.php; #    }     location ~ \.php$ {        #try_files $uri /index.php =404;        try_files $uri =404;        fastcgi_split_path_info ^(.+\.php)(/.+)$;        fastcgi_pass unix:/var/run/php5-fpm.sock;        fastcgi_index index.php;        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;        include fastcgi_params;    }  }   server {     listen       443 default_server;      ssl on;     ssl_certificate /jet/etc/nginx/SSL/website.crt;     ssl_certificate_key /jet/etc/nginx/SSL/private/website.key;       server_name  _;     root         /jet/app/www/website/public;         index index.php index.html index.htm;     autoindex on;      # Load configuration files for the default server block.     include /jet/etc/nginx/conf.d/*.inc;  #location / {            try_files $uri $uri/ /index.php; #    }     location ~ \.php$ {        #try_files $uri /index.php =404;        try_files $uri =404;        fastcgi_split_path_info ^(.+\.php)(/.+)$;        fastcgi_pass unix:/var/run/php5-fpm.sock;        fastcgi_index index.php;        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;        include fastcgi_params;    }     }   Wth could be going on?


2000s fantasy book, teen boy followed home by crows/ravens, feels a weird presence when entering his house and is rescued by a stranger

The book takes place in winter and starts off by following a young boy who just turned a certain age like 13 or in that range.  The boy notices that as he was walking back home that crows or ravens were following him and looking at him with intelligence.  As he passes each crow, it looks directly at him at caws while looking at him. The boy remarks on the strangeness but shrugs it off at first.  When the boy gets home, it is dark and there are street lights and as he is about to enter his home he feels a strange presence and turns around and some of the street lights are out and he feels someone watching him.    I don't remember much more than that in specifics. I want to say that something happens that night and the boy is rescued by a stranger who is fighting a battle with the people that were following the boy. I believe there is magic in there as well something that has to do with the seasons or night and day but i am not sure.


Is there a no-duplicate List implementation out there?

I know about , but in my case I need something that implements List, and not Set. So is there an implementation out there, in the API or elsewhere?  It shouldn't be hard to implement myself, but I figured why not ask people here first?


Isomorphism problem involving the Symmetric Group

Let $G$ be a group of order $24$ with no elements of order $6$. Prove that $G$ isomorphic to the symmetric group $S_4$.   This is what I did and I'm a bit unease about it since I didn't use that G has no element of order 6.  Let A = {1,2,3,4}. Suppose that G is acting on A by left multiplication.  Then $\phi$ : $G \longrightarrow S_A$ is a Homorphism.  By the First Isomorphism Theorem:  $ | \ker \phi| | |G| =S_A =S_4 $   But this says that $ \ker \phi = 1$ and thus $\phi$ is injective. This establishes that G is isomorphic to $ S_4$


After running sudo apt update, I have this error:  GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit -.mount is masked.   What is? How can I solve it?


Finding the eigenvalues of an $n \times n$ matrix

Compute the eigenvalues of the $n\times n$ matrix M defined by $$(m_{ij}) = \begin{cases} 1 - 1/n & \text{ if } i = j  \\ -1/n & \text{ otherwise.} \end{cases} $$  Using Wolfram Alpha, I found a pattern: for an $n \times n$ matrix, the eigenvalues are $0$ (with multiplicity $1$) and $1$ (with multiplicity $ n - 1)$. But how can I prove this fact? I didn't get anywhere with induction.  For example, in the $n = 2$ case, we have that $\text{trace M } = 1$, and $\text{det} M = 0$. So the product of the eigenvalues is $0$ (which means one eigenvalue is $0$) and the sum is $1$, so the other one must be $1$. This doesn't really work for higher orders though.


Singular homology $S^{n}$ with rational coefficients

What does $H_{i} (S^{n} , \mathbb{Q} )$ equal? Where this denotes singular homology with rational coefficients.


Why would a formula with = work but a simple == does not

I have a google sheet with rows that have some date values and other info to place on a gCal.  Date 9/4/2019 9/6/2019 9/5/2019      I am trying to run a loop that will only pull dates that are equal to a futureDate (which is today plus three days, currently 09/05/2019)  If I use the <= or => it works fine.  Pulls the correct dates and places them on my calendar.  I can't get the equal to futureDate to work.  I have spent hours thinking it has something to do with the date format but then the <= should not work either.  What am I missing here??  var today = new Date(); var futureDate = new Date(); futureDate.setDate(today.getDate()+3);  for(var i = 0; i<data.length; i++){      if(data[i][11] == futureDate) {       cal.createEvent(data[i][0], data[i][1], data[i][2], {location: data[i][3], description: data[i][10]}).setColor(data[i][5]);  //This one works and returns all dates that are not equal to futureDate if(data[i][11] <= futureDate) {       cal.createEvent(data[i][0], data[i][1], data[i][2], {location: data[i][3], description: data[i][10]}).setColor(data[i][5]);    I need only 09/05/2019 to return currently because today is 09/02/2019. (today + 3 days)


my website can no longer send email and I didn't even change the code

After receiving reports from my website assistant that he was unable to receive email resulting from a user performing an action that would generate an email to him, I decided to test a function on my site that worked in the past. I used the simple contact form to try to send an email to myself and my website assistant. Instead of the email going out, the remote servers rejected the email. When I looked in the server logs, I see this error reported from the yahoo server (into my exim_mainlog file)  "SMTP error from remote mail server after end of data: 554 5.7.9 Message not accepted for policy reasons."  I checked the account settings on my server through cpanel and   noticed that DKIM and SPF are enabled on the account.  Next to SPF, I see  "(v=spf1 +a +mx +ip4:64.15.69.254 ~all)"  Is it possible that I need to modify that SPF string to make the remote mail clients happy? I'm using WHM 11.52.2 build 5 and something makes me thing upgrading is a solution but at the same time, upgrading could wreck other parts of my high-speed website setup.  So without upgrading can I fix this problem? Does it really boil down to just a data configuration error that magically happened?


I have had some problems installing an Epson WF-7610 on a new computer running 16.04 I have downloaded the driver from the website above. When I go to the list of printers in 'add printer' I get WF-7525 (recommended). This doesn't work! I have another laptop which uses the same printer and this works fine. Any ideas?


I have an accompanied visa with my grandparents but because of some reason they cannot travel with me. I am above 17 years. Can I travel alone and will I be allowed to enter UK as my real aunt puts up there?


Can Antimatter undergo nuclear fission/fusion?

I was curious if antimatter could undergo nuclear fission/fusion with other antimatter. It makes sense, I was wondering if it would work?


using rmse and mape for model evaluation

ok, so I have a memory-based model to predict the values of variable X and I've also measured the real values of X. I have calculated both the RMSE and MAPE for the difference Xreal-Xpredicted. I know that there is absolutely no point in saying a model is good or bad if the RMSE value is less than a particular value. I was wondering though if there is a rule of thumb providing insights on the subject. For example my data range from 0 to 4 and I have an RMSE of 1,1. Is there any empirical rule suggesting this is a good/bad estimation?  thank you in advance   ETA: X may take all values within the range{-2,2}


Flagged "not an answer", flag marked helpful but answer still exists

I flagged , which was marked as helpful. So why does this post still exist?  Someone edited the post a few minutes back, so here's the original revision that I flagged:     Could you try with android:showAsAction="always" for the items in the menu.   I think this should be a comment.   If you are saying that I was wrong to flag this as "not an answer" then why did a moderator mark it as "helpful"?


In Windows we can add applications/batch scripts to open automatically on startup. Is there something similar in Ubuntu, or Linux in general?


Word similar to "collusion" but without negative connotation

I am writing a piece where multiple seemingly disparate (even juxtaposed, without a common mission) government organizations are combining their efforts in somewhat of an unpublicized task force.  This collaboration is not necessarily classified or secret, but it doesn't become known until when they make their bombshell announcement.     In a rare ______ of inter-agency cooperation, ...   What is a good word to describe this sort of arrangement that doesn't have the negative connotation associated with collusion?      EDIT: I'm looking specifically to include the unpublicized/secret aspect.  Also, I'm not tied to a noun answer per se, other parts of speech are welcome as well.


Approximation of sum using Riemann integral

$$\sum_{k=n+1}^{2n}\frac{1}{k}$$ We would like to approximate this sum using Riemann integral. My approach is following: Let $f:[n+1, 2n]\to \mathbb{R}$, $f(n)=\frac1n$. Let $P=(x_0, x_1,..., x_n)=(n+1, n+2, ..., 2n)$ Then $$\sum_{k=n+1}^{2n}\frac{1}{k}=\sum_{i=1}^{n}f(x_{i+1})(x_{i+1}-x_i)=\sum_{i=1}^{n}f(x_{i+1})$$ So, we have that $$\sum_{k=n+1}^{2n}\frac{1}{k}\to \int_{[n+1,2n]}\frac1xdx$$     I am not sure if I am ok, help me please understand these issues.


The \hl command from the soul package highlights spans of text with a backround color when color is loaded. When used on longer spans of text, some inter-line spacing remains uncolored, which is rather unpleasant to my eye.  \documentclass[a8paper, landscape]{scrartcl} \usepackage{color, soul} \sethlcolor{red} \begin{document}   This is some text \hl{of that some part should be highlighted. This part spans multiple lines}, which is easy on a8paper. \end{document}     I already tried to tinker with \setul, but increasing the height and depth there just enlarges the line height, leaving unchanged the spacing in between.  Is there a way to have the result look like this?    Answers do not have to be restricted to the package. (Meaning soul-less answers  are also welcome. ;)


Almost every time I turn my XBox on and start up Fallout 4, I am unable to use the "Continue" option because the most recent save is corrupt.  I instead use the "Load" option. Here, I can see that the last save I manually performed is perfectly fine, and load it with no problem. However, there is an additional, corrupt save with the same time stamp immediately after it.  This doesn't happen quite every time, but often enough that I'm surprised when there's no corrupt save waiting for me to delete it.  I've tried a few things to solve this, including exiting to the game's main menu before turning the XBox off, going out to the guide before turning the XBox off, turning it off immediately after saving, and waiting a while after saving.  Why do I get all these corrupt saves? Do others have this problem? How do I fix it?


Integral $ \int_{-\infty}^{\infty}\frac{x^{2}}{\cosh\left(x\right)}\,{\rm d}x $

I need to compute the improper integral $$ \int_{-\infty}^{\infty}\frac{x^{2}}{\cosh\left(x\right)}\,{\rm d}x $$ using contour integration and possibly principal values.  Trying to approach this as I would normally approach evaluating an improper integral using contour integration doesn't work here, and doesn't really give me any clues as to how I should do it. This normal approach is namely evaluating the contour integral $$ \oint_{C}{\frac{z^2}{\cosh\left(z\right)}\mathrm{d}z} $$ using a semicircle in the upper-half plane centered at the origin, but the semicircular part of this contour integral does not vanish since $\cosh\left(z\right)$ has period $2\pi\mathrm{i}$ and there are infinitely-many poles of the integrand along the imaginary axis given by $-\pi\mathrm{i}/2 + 2n\pi\mathrm{i}$ and $\pi\mathrm{i}/2 + 2n\pi\mathrm{i}$ for $n \in \mathbb{Z}$. The residues of the integrand at these simple poles are $-\frac{1}{4}\mathrm{i}\pi^{2}\left(1 - 4n\right)^{2}$ and $\frac{1}{4}\mathrm{i}\left(4\pi n + \pi\right)^{2}$, so that even when we add up all of the poles, we have the sum $4\pi^{2}\mathrm{i}\sum_{n = 0}^{\infty}\,n$, which clearly diverges.  Any hints would be greatly appreciated.


T is not compact and orthonormal sequence

I want to show that if  $\,T$ is not compact then there exists an orthonormal sequence $x_{n}$ and  $R>0$ such that $ \forall n\in \mathbb{N}\,\,\,\,\|T(x_{n})\|\geq R$. It is obvious by the definition of compact operator that we can find a sequence satisfying the above condition but how can we find an orthonormal one? Thank you.


How to give a consistent mathematical explanation to a paradoxical divergent/convergent phenomena.