I've used different USB bootable programs like Unetbootin to put an iso image into my USB and went into the boot menu to change the boot device but I get the message "missing operating system" before it starts my current OS (Kubuntu) again.  According to this () article: Some users have reported that some recent Unetbootin versions no longer let you select an USB drive formatted to NTFS and by formatting it to FAT, the Windows 7 installation fails.  What do I do? [Deadline for Windows 10 update is tonight!]  EDIT: I've already tried downloading WinUSB as well (one of the many programs I've tried) and I never got past downloading it because I get   N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.   in the terminal.  EDIT 2: I went into sudo nano /etc/apt/sources.list because I was going to try to comment a CD-ROM source, but it already was:  # deb cdrom:[Kubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial mai$   so the source code is not the issue..  The terminal tells me the problem is:  W: The repository http://ppa.launchpad.net/colingille/freshlight/ubuntu xenial Release' does not have a Release file. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.   I'm still looking for a way to solve this.. :( This is not a duplicate because I cannot download winUSB.  tried disabling the ppa from the source code and running the steps again  sudo add-apt-repository ppa:colingille/freshlight sudo apt-get update sudo apt-get install winusb   nothing new. Posted another question..


I provided personal information to a scam survey. What's my risk?

I filled out this survey to win a something. Then realized it was a scam. Felt really dumb. Anyhow, I gave my email, name, phone number and address. What can the do with the information I gave them?


Why did my "d" break when I screwed up a bind?

I was swapping some readline settings in my .bashrc earlier today and mistyped the following (bind since it's not in .inputrc):  bind "mark-symlinked-directories on"  I forgot to put a set in there before mark-symlinked-directories, the end result of which was that my "d" key stopped working in the terminal.  Lame.  Some messing around with other bindings indicated that whatever the first letter of the last "word" was would be unusable, i.e.,  bind "page-completions off" messed up c  bind "visible-stats on" messed up s  bind "completion-query-items 42" messed up i  My question is why?  What is bind doing that renders those keys useless, and why that specific key?


How do I have no default web browser, so the system asks what browser to use when I click on a link?

I use Internet Explorer for some things and Chrome for others. I'd like to have a choice when I click on a link of which browser to open the link in. Is this possible in Windows? I am currently running Windows 8, although there should be similarities between versions.  To the best of my knowledge this isn't possible.


Debian apt-get install asks for the DVD Binary

I have installed debian 8 jessie via usb stick on my thinkpad x250 (the laptop doesn't have any cd-dvd rom). Now when i want to use the synaptic or install some programms (especifically pure data) via: sudo apt-get install puredata i get this in terminal:  Media change: please insert the disc labeled  'Debian GNU/Linux 8.4.0 Jessie - Official i386 DVD Binary-1 20160402-13:26' in the drive '/media/cdrom/' and press enter  Why this happens and how am i supposed to insert a dvd when i haven't any dvd-rom? How can i fix this?


How can I initialize the const char array member of the class using initialization list?

#include<iostream>  using std::cout; using std::endl;  /* This example aims to test whether the default copy constructor and default assignment operator works for classes that has array member and whether initialzation list works for array member.  Test result: copy constructor and default assignment operator works for classes that has array member                          initialization list doesn't work for array member. */  class A{     private:         const char list[10];     public:         A(const char *l="Nothing");         void show()const;  };  A::A(const char*l):list(l){           //the compiler fails to initialize "list" }  void A::show()const{     for(int i=0;i<10;i++){          cout<<list[i]<<'\t';         if(i%5==4)             cout<<endl;         }     cout<<endl; }  int main(){     char name[10]="hello";     A a(name);     A b;     cout<<"Before assignment, b="<<endl;     b.show();     b=a;     cout<<"After assignment, b="<<endl;     b.show();     A c(a);     cout<<"After initialization, c="<<endl;     c.show();  }   The program fails to compile and throws an error message, saying that"incompatible types in assignment of 'const char*' to 'const char[10]". How can I achieve in initializing the const member list?


I can't get curl to download https://www.sicdm.caixa.gov.br/cadmut/login_internet_form.do on a CentOS 6.2 server.  The command curl -v -k -3 https://www.sicdm.caixa.gov.br/cadmut/login_internet_form.do yields:  * About to connect() to www.sicdm.caixa.gov.br port 443 (#0) *   Trying 200.201.173.93... connected * Connected to www.sicdm.caixa.gov.br (200.201.173.93) port 443 (#0) * Initializing NSS with certpath: sql:/etc/pki/nssdb * warning: ignoring value of ssl.verifyhost * skipping SSL peer certificate verification * NSS error -5938 * Closing connection #0 * SSL connect error curl: (35) SSL connect error   What I've tried so far:  1) Issue the very same curl command on servers hosted with other providers, on my linux dev machine and on my teammates machines: the page downloads just fine;  2) google for NSS error -5938, which did not provide a single helpful tip.  3) Ditch curl and use wget: won't work, since the remote server uses Transfer-Encoding:chunked, which wget doesn't play with.  4) Upgrade/downgrade/compile lastest version of Curl, NSS and OpenSSL: the problem persists.  5) Report the problem to the server provider. First they claimed it was a issue with the remote server certificate; I'm doubtful that's the case, since I've told curl do ignore certificate validation (-k flag).  6) Extract a tcpdump of the connection, where "funny" things where found (upper capture):    There are many transmission errors, and the server response to the "Client Key Exchange" phase never reaches our server - even though the ACK packet does! - note the 30s gap between packets 46 and 47. (this happens even if the firewall is disabled)  For comparison, curling paypal (lower capture) goes just fine.  7) Recontact the server provider, showing the tcpdump findings. They commented nothing about the dump, but said that they tried the command on other servers on their network, and the command failed the same way. Despite this, they still claim the problem is the remote server crappy certificate, and the way I handle it.  So, what am I missing?  PS: here are some version numbers:  curl -v   curl 7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.16.2.3 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2 Protocols: tftp ftp telnet dict ldap ldaps http file https ftps scp sftp  Features: GSS-Negotiate IDN IPv6 Largefile NTLM SSL libz   uname -a   Linux [redacted hostname] 2.6.32-220.23.1.el6.x86_64 #1 SMP Mon Jun 18 18:58:52 BST 2012 x86_64 x86_64 x86_64 GNU/Linux


I don't know why Asp.net MVC developers put the using directives inside System.Web.Mvc namespace as follows.  namespace System.Web.Mvc {     using System;     using System.Collections.ObjectModel;      [Serializable]     public class ModelErrorCollection : Collection<ModelError>     {          public void Add(Exception exception)         {             Add(new ModelError(exception));         }          public void Add(string errorMessage)         {             Add(new ModelError(errorMessage));         }     } }   When do we need to put  using directives inside a namespace scope?


In one part of my site, some accent characters (é,à...) are replaced by black question marks. It is for sure some encoding character but the thing is that everywhere the site displays well, except for the $html variable whose accent are corrupted and which is set this way    $html = <<<EOF  <div>...   <header>... EOF;   What is weird is that on my local machine, everything goes well but on my remote machine, it is failing. For information, I correctly set this <meta charset="utf-8">


I know that this question has already asked but no concrete answer has given!! My environment is Ubuntu 12.04 and I'm using eclipse-pydev as IDE.


Remove ugly borders around clickable cross-references and hyperlinks

I know that I can use  to make cross-references and hyperlinks clickable.  That makes the clickable areas outlined in fluorescent green, however.  How can I make the green boxes go away?


What are the differences between Ridge regression using R's glmnet and Python's scikit-learn?

I am going through the LAB section §6.6 on Ridge Regression/Lasso in the book  by James, Witten, Hastie, Tibshirani (2013).  More specifically, I am trying to do apply the scikit-learn Ridge model to the 'Hitters' dataset from the R package 'ISLR'. I have created the same set of features as shown in the R code. However, I cannot get close to the results from the glmnet() model. I have selected one L2 tuning parameter to compare. ('alpha' argument in scikit-learn).  Python:  regr = Ridge(alpha=11498) regr.fit(X, y)     R:  Note that the argument alpha=0 in glmnet() means that a L2 penalty should be applied (Ridge regression). The documentation warns not to enter a single value for lambda, but the result is the same as in ISL, where a vector is used.  ridge.mod <- glmnet(x,y,alpha=0,lambda=11498)   What causes the differences?  Edit: When using penalized() from the penalized package in R, the coefficients are the same as with scikit-learn.  ridge.mod2 <- penalized(y,x,lambda2=11498)   Maybe the question could then also be: 'What is the difference between glmnet() and penalized() when doing Ridge regression?  New python wrapper for actual Fortran code used in R package glmnet


Why the photon doesn't acquire mass with the Higgs mechanism?

I did the computation that from  $$(0,v)^{T}(\partial_\mu+igA_\mu^a\tau^a+i\frac{g'}{2}B_\mu)(\partial_\mu-igA_\mu^b\tau^b-i\frac{g'}{2}B_\mu)(0,v)$$  with $(0,v)$ being the expectation value of the Higgs field and $\tau, B_\mu$ being the generator of the SU(2) and U(1) group proves the mass term for the $Z_\mu$ and $W^\pm_\mu$ and not for the photon. That said if I rewrite the covariant derivative  in terms of the $Z_\mu, W^\pm_\mu$ and $A_\mu$ ($c_1,c_2$ being the constant dependent on $e,\theta_\omega$ for brevity): $$D_\mu=\partial_\mu-c_1[W_\mu^+(\tau^1+i\tau^2)+W_\mu^+(\tau^1-i\tau^2)]-c_2Z_\mu(\tau^3-\sin^2{\theta_\omega}Q)-ieQA_\mu$$ I don't realize how the term in $A_\mu^2$ doesn't give a mass term for the photon. Any hint is well appreciated.


How is maximum likelihood estimation method defined for non-continuous and non-discrete distributions?

Consider a task of estimating a parameter of a censored exponential distribution using maximum likelihood estimation. The typical approach to this question is presented in .  The linked answer asserts that  $$P_\lambda(X = x_i) = \left \{   \begin{array}{rl}     \lambda e^{-\lambda x_i} & \text{, if } x_i \leq t_i\\     e^{-\lambda t_i} & \text{, if }x_i > t_i\\   \end{array}\right.$$ is the likelihood function of the censored distribution. While it seems intuitive, the problem is that the distribution of $X$ is neither continuous nor discrete, so we can't apply the standard notions of likelihood.  Does the concept of likelihood generalize to such distributions? If yes, what's the general definition, and how does it apply to the distribution of $X$.


Is there any way to use commands to make a long delay? I do not want to use a dispenser to fire an arrow into a button, because I don't want to keep reloading it, nor do I want to use a lot of repeaters. Can anyone help with possible commands/layouts for this sort of idea?


Recover original data saved as "???????" from mysql database

While saving the information to the database field the settings were as follows:  character set: latin1 collation: latin1_swedish_ci   Once the users updated the information,i noticed that many information were saved as "?????????????? ??????????????? ???? ?????" (Question marks) to the database.  English(language) information were saved without questions marks. All other languages were saved with question marks.  Now i have changed the character set to utf8 and all the languages are saved properly.  The problem is that i need to recover the information which is saved as question marks.  eg:"?????????????? ??????????????? ???? ?????"  XAMPP Version: 5.6.19 Navicat version 11.0.17   Database server Server version: 10.1.10-MariaDB - mariadb.org binary distribution  Web server Apache/2.4.17 (Win32) OpenSSL/1.0.2d PHP/5.6.19 PHP version: 5.6.19  phpMyAdmin Version information: 4.5.1  Please help me to get the original data.


Is heat a form of energy or mode of transferring energy like work?

I have found somewhere that energy can be transferred by two modes, i.e., work and heat.  Moreover there are many differences between heat and energy; like energy is a state function and heat is not.  Considering all these, is heat a really a form of energy?


I want to replace the backslash in the string page_path\example_filename.txt with a forward slash.  I also want to be able to run this on a large file system and have it recursively search all directories.  I found someone on the web who said to use grep, xargs, and sed but I wasn't able to get it to work. I've been trying different variations on delimiters and escape characters, but didn't get it.  Here is the command I was trying to run: grep -lr -e 'page_path\\' * | xargs sed -i 's/page_path\/page_path//g'  Thanks in advance.


What is the point of changing the manga's storyline for the adaptation?

As the title states, why do producers/script writers working on an anime adaptation change diverge from the story in the manga?, may it be small or a huge change.From a logical perspective  when adapting an anime, changing the storyline from the source makes no sense at all, since it may have been what made it so popular in the first place. So why do they do it?. Cough cough promised neverland.


how to keep a footer at the bottom of the page, even if the content grows?

I'm developing a single-page and I have a shared footer layout, I want to keep it at the bottom of the page always and even I would like to know if there is a way not to visualize it in some route even though it has been declared in the app.component.html   I have tested on scss all possible footer positions  app.component.html  <div class="grid-container"> <main [@fadeAnimation]="o.isActivated ? o.activatedRoute : ''"> <router-outlet #o="outlet"></router-outlet> </main> <rb-footer class="footer"></rb-footer> </div> <rb-modal></rb-modal>   app.component.scss  :host {     .grid-container {       display: grid;       grid-template-rows: auto 1fr auto;       grid-template-columns: auto;       height: 100vh;     }  .footer {   position: initia   width:100%;   height:40px;    }    }


What is the difference between these two initialization of List :  List<Integer> aa = new ArrayList<>(); ArrayList<Integer> aaa = new ArrayList<>();


How do you find the standard deviation of the weighted mean?   The weighted mean is defined: $\bar{x}_w = \frac{\sum{wx}}{\sum{w}}$  The weighted standard deviation (since it is not specified, I take it as of the distribution) is defined:  $$s_w = \sqrt{\frac{N'\sum_{i=1}^N {w_i(x_i-\bar{x}_w)^2}}{(N'-1)\sum_{i=1}^N{w_i}}},$$  where $N'$ is the number of nonzero weights, and $\bar x_w$ is the weighted mean of the sample ()  For an unweighted sample, calculating the standard deviation of the mean from the standard deviation of the distribution is .  How do I calculate it for the weighted mean, and how is the expression derived?


What is the world record for the longest D&D marathon?

I have been looking for a while to find the world record for the longest Dungeons and Dragons marathon because me and my friends had a plan to try and attempt to beat it and give the money from the stream (if we get any) to my school's Gaming and Anime Club.


ReadOnlyCollection or IEnumerable for exposing member collections?

Is there any reason to expose an internal collection as a ReadOnlyCollection rather than an IEnumerable if the calling code only iterates over the collection?  class Bar {     private ICollection<Foo> foos;      // Which one is to be preferred?     public IEnumerable<Foo> Foos { ... }     public ReadOnlyCollection<Foo> Foos { ... } }   // Calling code:  foreach (var f in bar.Foos)     DoSomething(f);   As I see it IEnumerable is a subset of the interface of ReadOnlyCollection and it does not allow the user to modify the collection. So if the IEnumberable interface is enough then that is the one to use. Is that a proper way of reasoning about it or am I missing something?  Thanks /Erik


I use gb4e for my linguistic examples. When the example is long, gb4e breaks it into two lines (of the first and second, glossing, lines). However, I sometimes want to break it at a certain point. How can I do that? (I can't find any method in the gb4e document.)  A MWE is as follows. I'd like to break the line after the first occurrence of the word 'Mink'. If I do it in the second way, unwanted spaces appear between the lines. (I'm using xelatex.)  \documentclass{article} \usepackage{fontspec} \usepackage{gb4e}  \begin{document}  \begin{exe} \ex \gll thu-mi-t-əm =k'wa Mink.  chichiya7-u-s =k'wa Mink te= c'estaya\\ go-RLT-CTR-PASS =QUOT Mink grandmother-PST-3POSS =QUOT Mink DET= knothole\\ \glt `Mink went towards it. The knothole was Mink's grandmother.'\\ \end{exe}  \begin{exe} \ex \gll thu-mi-t-əm =kʼwa Mink.\\  go-RlL-CTR-PASS =QUOT Mink\\  \gll chichiya7-u-s =kʼwa Mink te= c'estaya\\ grandmother-PST-3POSS =QUOT Mink DET= knothole\\ \glt `Mink went towards it. The knothole was Mink's grandmother.' \end{exe} \end{document}


I have to install libboost-all-dev 1.62+ and I found it here  because I need 1.65.1, but I don't understand how to switch to bionic. Looks like by default apt-get tries to install the package from xenial, but there are no 1.62+.  Actually, I use Docker, maybe it's possible to solve the problem somehow  FROM ubuntu:latest  RUN apt-get update -q && apt-get -qy install \     git sudo cmake build-essential cuda-8-0 \     libboost1.65-all-dev   It throws an error on installing libboost1.65-all-dev


One of my laptop's keys has fallen off. Is there any way I can remap another key to serve as that key?  I'll 'sacrifice' the other key because I never use it.


Is there a way to modify the timestamps of multiple git commits?

For a few days I was using a computer with a wrongly set clock (without realising) and made a bunch of commits that now have the wrong timestamps. I'd like to know if it's possible to bring these timestamps forward by a set amount (2 weeks).  The commits are all sequential and I've already pushed them to Github.  I presume I'd need a script to do this (if it's possible at all) but I don't know where to start.


Why can't I answer to `rm -i`'s interactive prompt?

This is the console output when I try to use find | grep ... | args rm -i to delete a bunch of files, but confirm deletion of each one: user@host:/tmp> touch test1234 user@host:/tmp> find -maxdepth 1 | grep /test1234 | xargs --no-run-if-empty rm -i rm: remove regular empty file './test1234'? user@host:/tmp> y If 'y' is not a typo you can use command-not-found to lookup the package that contains it, like this:     cnf y  Basically, rm -i exits before I am able to enter my answer.


Is it possible to make an ASP.NET MVC route based on a subdomain?

Is it possible to have an ASP.NET MVC route that uses subdomain information to determine its route?  For example:   user1.domain.com goes to one place user2.domain.com goes to another?   Or, can I make it so both of these go to the same controller/action with a username parameter?


I have windows 7 in 32 bit mode and apparently it doesn't know how to use more than 3.4 GB of RAM, but I have 8. I read about the PAE thing, and it is enabled on my system but it still limited to 3.4 :(  Is there any way to fix this, without upgrading to 64 bit?


Auto completion of accents and tilde OSX

I've been working on macs for a couple of years now, and recently switched jobs (Software dev). Before when I  was typing something like "e would not automatically merge into ë. This is really annoying in terminal And I don't know how to disable this as of now (I googled but not sure what I should be looking for). One of the most annoying things I encountered was when I need to go to my home dir in terminal (using tilde) when tying by default it will complete to ˜/ whilst I would like to see it act like before: ~/ which requires me to type an extra space.  I never need the auto completion for accents since I'll use the menu which opens when you hold the key instead.  Does anyone know what could cause and get rid of this behaviour.  My keyboard settings are US-Internation (which is normal in the Netherlands) and my MacBook is fully updated to El-Capitan.


How do I get iTunes to see my iPhone 4S on Windows 8.1?

When I connect my iPhone 4S to my Windows 8.1 laptop, iTunes doesn't see the phone.  I can browse the DCIM folder via Windows Explorer, but iTunes doesn't see the device.  Which is particularly unfortunate for me, as I don't have a Windows 7 PC to try and although I've been told that the phone has (just) been unlocked from the network, I think I have to sync it with iTunes in order for the phone to apply the unlock... is that right?  Is there some work around for this?


Are there good reasons to install 120V 20 AMP receptacles "upside-down" instead of in conventional upside-up position?

In the US, most 15 and 20 AMP receptacles are installed with the hot and neutral on the top and the ground below.  However, sometimes they are installed the other way around, with the ground above.  I have heard vague explanations of safety given for this - eg, plugs are more secure in the upside-down position or a wire falling from above that lands on a ground is essentially harmless whereas landing across the hot and neutral results in an extremely dangerous short.  Do these explanations hold water?  Are there other reasons?  Is it just superstition?


Bezier Circle looks flattened like Tapeworm

This problem is pretty simple. I am trying to make a perfectly round tube like a pipe. I made a bezier circle and increased the depth to make it thicker but now it looks like a flattened oval. How do I make this tube perfectly circular? Here is what it looks like.   Also here is a link to the file.


Is there a resource with the average load factor on a specific flight?

I almost always seem to be traveling on full flights. So almost never have the luxury to be able to change seats or even rows.  Is there any way to find out beforehand if a specific flight is on average not fully booked?  I am looking for an average load factor on a specific route.


What is a word for those times where you can't describe something well?

I need a word that describes when you're trying to explain an idea to someone, but you just can't word it right. Like when the words are just on the tip of your tongue, but you simply don't know them, or they don't exist. I want the word to describe the feeling, or even the situation. The feeling is kind of like trying to describe the color blue to a blind person, but more about the speaker's incapability to communicate the idea, rather than the listener's incapability to understand.


Trying to insert multiple rows in my table in SQL.Always showing SQL Command not ended properly

I am trying to insert multiple rows into my table using the below query : INSERT INTO TABLE2(ID) VALUES(1),(2) .It is showing SQL Command Not Ended. Is it some syntacital error?I have rechecked but still not clear what's going wrong.


How will you explain responsive web design to a potential employer?

I have been working as a UI/ UX engineer for more than three years. Three years aren't enough to have great knowledge but I have good knowledge on giving the user a good visual experience and a good experience while using the apps or web-sites I have developed.  I am now searching for a new job. I have been asked often if not most of the time on what is responsive design? I think the people who conduct interviews come in with a few points on responsive web-design and expect the candidate to answer those specific points. RWD(Responsive web-design) is a vast subject and keeps evolving from time to time. Which brings me to a quote from Albert Einstein "If you can't explain it simply, you don't understand it well enough." RWD is a highly subjective topic and doesn't have any hard and fast rules for its creation. I cannot copy Apple's website for my client and expect him to reap profits same as Apple. It works for Apple because it is Apple. I truly believe that there are no such hard and fast rules for RWD and that design and UX shall always evolve through time. Now what happens in the interview: I explain a few points and give them a few examples of good UI/ UX web-apps, websites and apps even quote a few designers, so far it's not been fruitful.  My question to everyone here?  How will you summarise in a few points what is responsive web-design?


When I try to install ubuntu cd through this throws me this error     this kernel requires an x86-64 cpu but only detected an i686 cpu   I wonder what happens and how to fix it


Baby Rudin Theorem 2.23 — How do we know a limit point exists for the complement of an open set?

In Principles, Rudin states the following in his proof of Theorem 2.23 (that within a metric space, a set $E$ is open iff its complement is closed):  Suppose $E$ is open. Let $x$ be a limit point of $E^c \dots$  How do we know such a limit point exists?


this is my first time using Ubuntu 14.04 version.  I'm not sure what I've done, but I can't shut down my laptop. But if I log in as the guest, then it will shut down if I press the button and I'm not getting used to terminal. How can I solve the problem?


What would be the the mathematical equivalent of this excel formula? =PMT()

I need to create a JavaScript form that does the same calculation as this =PMT() function.   mortgage = 220000 rate= 4.75% term = 30   The example formula I have is =PMT(4.75%/12,30*12,220000*-1)  What would be the equation for this function? I tried to look up this function but it doesn't explain it very well.


I have multiple files whose names look like this  2313_ABCDEAUG2014_PQRST_0_.pdf 3244_ABCDEAUG2014_PQRST_0_.pdf 4234_ABCDEAUG2014_PQRST_0_.pdf   t want to rename the file in the following format.  AZ-2014-08-2313.pdf AZ-2014-08-3244.pdf   Please suggest.


Glucose lowering agents consist of multiple subcategories of drugs, including metformin, DPP-4 inhibitors, and insulin and analogues.   My question is how should I write a list with an "and" in one of the items? in this example: is "and 'insulin and analogues'" right?


How does Damage Resistance and Successful Save interact?

In my campaign, I have a Barbarian with Primal Path of Bear totem. Bear totem gives damage resistance when raging.   During battle the barbarian is targeted by a breathe weapon. And makes his save for half damage. Does his damage resistance then kick in to halve the damage again?  My thinking is that the Successful save means he somehow managed to avoid half the impact of the attack. Then his damage resistance would kick in to halve the damage he did take. For example, the breath attack rolls 30 lightning damage. The successful save means he was only hit with 15 lightning damage. Then his Damage Resistance kicks in and he looses 7 HP.


The regex -?\d+ [+|-|*|/] -?\d+ matches expression 1 + 3 without any problems also 1 + -2 without any problems, but I don't know why it does not match 1 - 2. Could you explaing why it does not match the - char correctly?  By my regex I wanted to achieve:   optional - at the beginning string of digits whitespace then operator then whitespace optional - before second stringof digits


Is it possible to travel from Panama City to Medellin, Colombia by car/bus?

I'm from Brazil and I'm planning to fly to Panama and then take a bus from Panama City to Medellin, is it possible?  Direct flights are so expensive!


Linphone installation: questions about remote gnome

I am going through the steps of installing Linphone, following this.   When I typed the command flatpak --user install --from   Terminal said The application com.belledonnecommunications.linphone depends on runtimes from  configure this as a new remote 'gnome'? (y/n)  I wasn't sure but I said yes to that.  Then Terminal said: Required runtime for com.belledonnecommunications.linphone/x86_64/4.4.1 (runtime /org.freedesktop.Platform/x86_64/1.6) found in remote gnome. Do you want to install it? (y/n)  Just wasn't sure what this all means and the implications.


Will 18.04.5 upgrade to version 20 through GUI or should I force it?

I've been waiting for my Ubuntu to give me that nice "Ubuntu 20 is now available" prompt since August the 6th, to no avail. 18.04 just keeps updating itself. Today I'm not in a particular hurry but merely curious: is it even supposed to give me this prompt? Or maybe GUI upgrades have been cancelled long ago and I have to force it through the console? Or is my software updater misconfigured?


I see a lot of job ads on SO, I've searched through them as well. It seems, however, that the ads are very broad in their targeting.  What I would like to see is ads based on tags.  First, it should display ads with relevant tags in your favorites before ads without relevant tags.  Second, it should place more weight on tags that you've got answer points in, allowing things that you're interested in or good at to be first.  This will keep the interesting stuff towards the top and encourage good answers within the community. It will also make the job lister happier, as they'll be able to get their listing seen by relevant developers faster.


I'm currently running Ubuntu 17.04 on my VPS. I want to go back to 16.04 since 17.04 is at end of life. I have a few remote systems that automatically log into this server using authorized keys. If I start fresh, how can I make sure those machines will still be able to log into the server. I do not have physical access to the remote machines.


I'm working with Jasper for PDF generation and have a template that is used to generate more or less the same document with different number of columns. Thus, in some cases I need to control the width of columns explicitly by setting predefined column width. Is there a possibility in Jasper-Framework that enables tags like in following example. <jr:column width="$P{CALL_PARAMETER}" uuid="735c1cbc-08d0-11eb-adc1-0242ac120002">  The goal is to pass CALL_PARAMETER to Jasper at some point of time and not to hardcode into template. Similar code results at runtime exception.


As you might have seen from my history I had a very bad advisor who deliberately underpaid me, stole my research work and undermined my career at multiple phases.  Now I am done with my university and leaving next month. A professor in my department had been very supportive of me during these times, giving me advice on how to handle this situation, gave me recommendation letters to apply for PhD programs at other universities and also got me a internship. I just want to thank her for her help. I usually would have got a champagne or something but I know she doesn't drink alcohol. Any advice?


can I reflectively instantiate a generic type in java?

Is it possible to reflectively instantiate a generic type in Java? Using the technique described  I get an error because class tokens cannot be generic. Take the example below. I want to instantiate some subclass of Creator that implements Creator. The actual class name is passed in as a command line argument. The idea is to be able to specify an implementation of Creator at runtime. Is there another way to accomplish what I'm trying to do here?  public interface Creator<T> {     T create(); } public class StringCreator implements Creator<String> {     public String create() { return new String(); } } public class FancyStringCreator implements Creator<String> {     public String create() { return new StringBuffer().toString(); } } public static void main(String[] args) throws Exception {     Class<?> someClass = Class.forName(args[0]);     /*ERROR*/Class<? extends Creator<String>> creatorClass = someClass.asSubclass(Creator.class);     Constructor<? extends Creator<String>> creatorCtor = creatorClass.getConstructor((Class<?>[]) null);     Creator<String> creator = creatorCtor.newInstance((Object[]) null); }   Edit: I like Marcus' approach as being the most simple and pragmatic without circumventing the whole generics thing. I can use it in my situation because I can specify that the class passed must be a subclass of StringCreator. But as Ericson pointed out the generic information is still there at the type level, just not at the runtime level so it is still possible to reflectively examine whether a given class implements the correct generic type.


How to split output lines into multiple lines (only lines not files)?

My requirement is display output lines into mutliple lines  My code is:  #!/bin/bash dir="$1"  echo -n "file size:" du="$(du $dir -hab | sort -n -r | tail -1)" printf "%s\n" "echo "$du""   It's showing output as:       file size:echo 0 ./.config/enchant/en_US.dic    My expected output is:  file size: 0 ./.config/enchant/en_US.dic    should be displayed like above. The path should be in a new line with one tab space.


Shouldn't we increase the required reputation to answer a protected question?

I sometimes see the protected questions not well answered by 20 rep user. So I thought it may be better to increase required rep to answer protected question. By this, we can:   increase the answers level decrease the number of answers posted for a question encourage OP users to earn rep for answering some questions


How the datatypes in java get converted to common type?

Someone please explain me how the below code prints 8.800000095367432.  class Test { public static void main(String[] args) {     Double object = new Double("2.4");     int a = object.intValue();     byte b = object.byteValue();     float d = object.floatValue();     double c = object.doubleValue();      System.out.println(a + b + c + d );  } }   Dear Pavel,The question in another link regards to javascript. I was wondering how is it in Java.  To make it more clear, The below one prints 6.4   Double object = new Double("2.4");         int a = object.intValue();         byte b = object.byteValue();         double c = object.doubleValue();          System.out.println( a+c+b);   Where as,   Double object = new Double("2.4");     int a = object.intValue();     byte b = object.byteValue();     double c = object.doubleValue();     float d = object.floatValue();     System.out.println(a + c + b + d);   prints 8.800000095367432.


Random in Java often generating same value

I'm using this to generate values between 5 to 13   int randomGeneratedLevelValue = ThreadLocalRandom.current().nextInt(5, 13);   How to make same matches fewer?


Submit the same paper to several journals/conferences

(N.B.: This isn't a duplicate of , though the question is related.)  I've written a paper and am looking for journals or conferences where I could present it. I intend to send the same work (with only minor changes to fit length restrictions, etc.) to several journals or conferences organizers, at the same time. The goal is not to actually publish the same work in several journals or talk about it in several conferences, but to do that in a single journal or conference, as quickly as possible. I have two things in mind:   The review process is typically very long. If my paper is rejected by a group of reviewers, I'll lose several months during which I could have found other prospects. This is made worse by the fact that calls for papers tend to occur at about the same time. For conferences, I can't know in advance whether my institution will accept to cover the costs. If I'm accepted to a conference and my institution refuses to cover the costs, I'll have to wait for a new opportunity, which might itself become void, and so on.   Is it ethical to submit the same paper to several journals or conferences at the same time, provided that, if my paper is accepted by several publishers/organizers, I follow up with only one of them, and disengage from the others?  And, if this is possible, how exactly ? (Should I explicitly inform the publisher or the organiser of the conference that I'm submitting the same work somewhere else ? Should I tell them where exactly I'm submitting the paper ? Should I tell them after the fact if I find a new opportunity in the meantime ? etc.)


Student missing exam for “medical reasons”

I have a student who failed an exam I gave three months ago and was supposed to show up for a remediation exam this week. The date was announced long in advance, and the student neither showed (all the others did show up) nor warned me. Now, she is asking for a new exam date, saying she was absent due to “medical reasons”. She produced a certificate that she was seeing a doctor at the time, but nothing indicates that it was an urgent need (rather than, say, a scheduled appointment).  How would you handle such a case? I asked the administrative staff at my institution, and they told me to proceed as I saw fit. Should I ask a more specific justification? In what form?


I was playing Dark Souls II on my pc a lot. After about 200 hours of ingame time I found that I cant summon or invade anybody. I tried new characters and reinstalling but it didn't help. So any tips, and reasons. P.S. I didn't used any cheats.


The effect of light from the sun had the affect of allowing john to see further.   True, not true? Effect is a verb, so light is an effect: affect alters something, so john seeing further was the affect of lights effects??????????


Relationship between the probability and likelihood functions

I've read a number of different explanations trying to understand the likelihood function, and I understand the purpose of it, but some statements sound contradictory.  Consider observed data X, model parameters M, likelihood function L(M|X), and probability P(X|M).  I keep seeing it written that L(M|X) = P(X|M). At the same time, they say that the likelihood is not the same thing as the probability and L is not a probability density function (pdf).   What does it mean to say they are not the same thing but equal?  How could L be equal to a pdf, but not be a pdf?  Reference to one of the places I've read this:


Proof If $AB-I$ Invertible then $BA-I$ invertible.

I have these problems :   Proof If $AB-I$ invertible then $BA-I$ invertible. Proof If $I-AB$ invertible then $I-BA$ invertible.   I think I solve it correctly, But I'm not so sure, I'll be glad to receive feedback.   If $AB-I$ invertible then :  $$\det|AB-I| \neq 0 \implies \\ \det|A-I||B| \neq 0 \implies \\ \det|B||A-I| \neq 0  \implies\\ \det|BA-I| \neq 0$$    Therefore $BA-I$ invertible.   If $I-AB$ invertible then :   $$\det|I-AB| \neq 0 \implies \\ \det|I-B||A| \neq 0 \implies \\ \det|I-BA| \neq 0$$  Therefore $I-BA$ invertible.


How exactly do protons and electrons interact with each other?

How do these particles exchange information about charge and position between themselves, even though there's mostly empty space between them?  Also what happens if a free electron passes closer to a nucleus of a hydrogen atom than its own electron?   My random guesses so far:   Proton won't react because it's somehow locked with its existing electron Proton will catch it and release the previous one  Proton will catch it and keep both of them with half the force Existing electron will simply repel incoming one Something else?


How can I replace a literal \n with a newline character? (on OS X)

I have a script which pulls something out of my shell history and saves it to a file, but if there is a newline in the history entry it gets returned to me with a literal \n instead of the newline character.  I'd like to replace the \n with a newline before saving it to the file.  I'm on OS X, and figured the problem might be the BSD-based sed that ships with OS X (that always seems to be the problem when sed isn't behaving!)  so I tried with gsed, and what was failing with sed worked on the first try with gsed:  history -1 | awk '{$1=""; print}' | gsed -e 's/^[[:space:]]*//' -e s/'\\n'/"\n"/   But if at all possible I'd like something that'll work with the default utilities (whether sed or something else) on both Linux or OS X, since I can't count on gsed being installed on OS X, and since GNU sed is the normal sed for Linux there is obviously no need for gsed.


I ran it once, but my terminal native language went back to Finnish. I've tried unsuccessfully .bashrc and .profile.   I have followed the thread  about How to set all locale settings in Ubuntu. I have also tried to setup English as locale:  sudo update-locale LANG=en_EN.UTF-8 LC_MESSAGES=POSIX   But output:  *** update-locale: Error: invalid locale settings:  LC_NAME="fi_FI.UTF-8" LC_TIME="fi_FI.UTF-8" LC_IDENTIFICATION="fi_FI.UTF-8" LC_NUMERIC="fi_FI.UTF-8" LC_MESSAGES=POSIX LANG=en_EN.UTF-8 LC_MEASUREMENT="fi_FI.UTF-8" LC_ADDRESS="fi_FI.UTF-8" LC_PAPER="fi_FI.UTF-8" LC_MONETARY="fi_FI.UTF-8" LC_TELEPHONE="fi_FI.UTF-8"     Where can you put export LC_ALL=C?


When should one use the "recent past"? How much time should have passed?

When we can use "recent past"? How much past time qualifies for "recent past"?


Movie where girl who lives with father's talking head and repairs androids, mistakes protagonist for android

Two scenes from an unidentified sci-fi movie have started to pop into my head while browsing scifi.stackexchange:  Scene #1: A girl is talking with her father. They might be on a space station but not for sure. He is seen as a head atop a large dark box, reminiscent of someone standing inside an iron lung, but he could also be a head on top of a machine.  Scene #2: The girl is tending to a number of life-like robots/androids, some partly disassembled. Someone is singing. This appears to be her job. What is presumably the protagonist of the movie appears along the androids and is startled when the girl thinks he's an android in for service and tries to inspect/unscrew/dismantle him. She apologizes with a reference to 'not seeing many people here, except her father'. I believe the protagonist may have been fleeing or hiding up until then.   It was a color movie, seen on TV no earlier than 1986, but could have been made anytime from the early Seventies onward. I'm guessing the movie had a tame rating as I was a kid at the time and must have seen it on daytime TV. The kind that might have made good MST3K material.


What are the technologies and programming decisions that make Google able to serve a query so fast?   Every time I search something (one of the several times per day) it always amazes me how they serve the results in near or less than 1 second time. What sort of configuration and algorithms could they have in place that accomplishes this?  Side note: It is kind of overwhelming thinking that even if I was to put a desktop application and use it on my machine probably would not be half as fast as Google. Keep on learning I say.    Here are some of the great answers and pointers provided:      Hardware - cluster farms and massive number of cheap computers Caching and Load Balancing


Why do we need null-homotopy to follow that a vector field is conservative if its curls is zero?

so let $\vec{v}: \Omega \subset \mathbb R^n \to \mathbb R^n$ be a vector-field.  Now we know:  (I) $\vec{v}$ conservative $\quad\Rightarrow\quad \nabla\times\vec{v}=0$  If further, $\Omega$ is simply-connected i.e. path-connected and null-homotopic, we can also state:  (II) $\nabla\times\vec{v}=0 \quad \Rightarrow \quad \vec{v}$ is conservative.  Question: Why do we need null-homotopy for (II)?


Asked question as guest, answered question on a beta Stack Exchange site with using my Facebook account. In a redirection loop

I asked a question on  as a guest user. I then answered a question on a beta Stack Exchange site ( - my professional expertise). I chose to sign in via Facebook to answer a question I could help with.   I am now trying to complete my sign in to participate on English Language & Usage and cannot. I have tried using the "sign in with Facebook" link to no avail.   Should I delete my account with Arts & Crafts?   The confirmation email I receive says, "Almost done! Click here to complete your registration."   Click → I'm sent to Stack Exchange saying, "Forgot your password?"  I would rather not go through Facebook and use my guest name, but it is already linked to my Facebook email.


I have bought a new pair of road bikes.  I am a triathlete (Sprint mostly) and I am interested to know, what computer should I buy now? wired or wireless?  I mainly do not like wireless things (I don't do wireless accessories - they tend to fail on you when you most need them).  The reasons I may consider which type to buy will be: - Price (wired usually lower) - accountability - (wired will less fail)  I can only think of why NOT to buy a wireless computer, and would like to know your inputs as well please.


Installing windows on multiple computers at the same time

i need to install windows on a 150 computers for a bank, i've never done anything like this before, so if anyone can help me find a fast efficient way to do so, they are IBM computers all with the same hardware specifications, brand new


public static void main(String args[]) throws IOException     {         String s1="abc";         String s2="xyz";         String s3="abcxyz";          String s4=s1.concat(s2);         System.out.println(s4);         @SuppressWarnings("unused")         String s5=s1+s2;          if(s3==s4)         {             System.out.println("true");         }         else             System.out.println("false");     }   Why the o/p is coming as false? According to me it should be true. Can someone please explain


system of ode with non-constant coefficient matrix

I am sorry but I haven't learn any method to solve this kind of problem if the given matrix is non-constant.  $$\begin{pmatrix}x\\y\end{pmatrix}^\prime=\begin{pmatrix} 1&-\cos t \\ \cos t & 1\end{pmatrix}\begin{pmatrix}x\\y\end{pmatrix}$$  Thanks


Prove there is no homomorphism from $Z_{16} \oplus Z_2 $ ont $Z_4 \oplus Z_4$

Prove there is no homomorphism from $Z_{16} \oplus Z_2 $ onto $Z_4 \oplus Z_4$   I have no idea at all how to attempt such question. I have read some solutions in which we find the cardinality of $kerm\phi$ for some $\phi mapping $ that is onto using the first theorem of homomorphism.  After that I don't understand anything  Is there a general approach to these questions ?


A number of questions "has been" or "have been" asked?

Formally, is it correct to write:     A number of questions has been asked here.   or:     A number of questions have been asked here.   As a non-native speaker of English, I would prefer the former: the subject seems to be "number", therefore the verb ought to be singular, I'd say. However, the latter seems more common, and therefore I believe that my gut feeling is just plain wrong — but I would really like to have a definite answer.  Moreover, is it the same for "a myriad of", "a plethora of", and so on?


I want to switch to French locale. So I tried the below command:  myUbundu@myUbundu-desktop:~$ export LC_ALL=fr_FR   But I am getting the warning  -bash: warning: setlocale: LC_ALL: cannot change locale (fr_FR)   How to set the locale to French? Do I need to install additional packages?


Conflict between babel and TikZ quotes library

The MWE below gives error language@active@arg" has extra }.  \documentclass{article}     \usepackage[T1]{fontenc}     \usepackage[utf8]{inputenc} \usepackage[english,slovene]{babel}%     \usepackage{tikz} \usetikzlibrary{quotes}  \begin{document}     \begin{tikzpicture} \draw (0,0) edge ["right", ->] (2,0);     \end{tikzpicture} \end{document}   Cause for it is option slovenian in babel which seem to redefine " somehow (if I remove this option, MWE work fine). Please, help me fix this error.


I know we can use both fruit and fruits (countable noun and uncountable noun):   The fruit began to rot. The fruits began to rot.   What has confused me is passion fruit because it has the word fruit in it!  Is passion fruit a noun, or is it an adjective (passion) and a noun (fruit)? I assume the former but I am not sure because of the singular/plural forms of mouse/mice (in regards to the animal and computer equipment — same word, but different meanings). This is why I am questioning my own ears when I say the following out loud:    There are many passion fruit in this bowl. There are many passion fruits in this bowl.   I have read  which is nearly a dupe other than it doesn’t specifically state by region, and although fruit is used as an example I’m not sure if it applies as I’m talking about a different noun.  So my two questions are   Are all four examples acceptable in English? Are all four examples acceptable in American English?


How to do color correction on multiple display devices?

Each display device renders colors in their own way. E.g. Apple's retina display renders colors in a more vivid way then an LG display device. The photo editor has to deal with this problem. I use my own taste when performing color correction or improving (selective) color saturation. Sadly, when a color suits my taste on my screen, it doesn't on another screen.   How can I find the ideal color saturation balance taking multiple display devices in mind?


It's been more than a month since I have started using . It has these users with user names in the format of "user-random number". I have observed them in some of the stack activities, most of the time asking questions.   Does the moderators create them for their own purpose. If yes what purpose do they serve?   I mean a user is free to have any user name. But it's just a hunch that such users are actually moderators. I may be wrong; just need some clarification.


Can I temporarily stop update notifications for one project only?

Is there a way I can tell Drupal not to notify me about a particular version of a module? For example, if it isn't security related and I choose not to update one module but would like to receive notifications about other modules (or future versions of the module in question)?  The Drush command from  to  is close to what I want except if there are future security updates I would still like to know about it, just no more notifications for this particular version.  drush pm-updatecode --lock=module_to_ignore


Can I skip my train leg booked with a KLM flight?

I have a flight booked form Cairo to Amsterdam Schiphol via KLM and then a Thalys train from Amsterdam Schiphol to Brussels. As Brussels is not my final destination anyway I want to intentionally skip the train from Amsterdam airport to Brussels Midi. I have read many reviews about skipping a flight leg can lead to cancelling your entire flight but does the train booked with the flight included in this rule? What are the risks?


Is there a site to play Go online against a computer, in 2018?

Apparently there's an old question  already but that's in 2014.  As we know AlphaGo/Master/Zero permanently changed the Go world, and many AI are competing the “2nd strongest” after AlphaZero retired. Is there a site to play Go online against one or (nowadays) more computers?


Assuming the following code:  #include <iostream> #include <stdint.h>  class FooBool { bool a; };  class FooUint16 { uint16_t a; };  class FooBoth { bool a; uint16_t b;};  class FooThree { bool a; uint16_t b; uint16_t c; };  int main() {     // Expected 1; Result: 1     { bool a;      std::cout << "bool:      " << sizeof(a) << std::endl; }     // Expected 2; Result: 2     { uint16_t a;  std::cout << "uint16_t:  " << sizeof(a) << std::endl; }     // Expected 1; Result: 1     { FooBool a;   std::cout << "FooBool:   " << sizeof(a) << std::endl; }     // Expected 2; Result: 2     { FooUint16 a; std::cout << "FooUint16: " << sizeof(a) << std::endl; }     // Expected 3 (1 + 2); Result: 4     { FooBoth a;   std::cout << "FooBoth:   " << sizeof(a) << std::endl; }     // Expected 5 (1 + 2 + 2); Result: 6     { FooThree a;  std::cout << "FooThree:  " << sizeof(a) << std::endl; }      return 0; }   Where does the extra byte for FooBoth and FooThree come from?  It's not using any virtual classes, is it? Is there an overhead per variable? If so, why is there only one in FooThree?


How can an interface implement two different algorigms for the same method

Hi I was watching a video on the "strategy pattern" and I understand his explanation on paper but I have no idea how it would look in code because I have never worked with interfaces before and his example relies heavily on the use of interfaces. Here is a screen shot of the UML diagram as a reference:  The goal was to have different implementations of the quack() method. SimpleQuack and NoQuack How would this look in Java code? Lets say that the City Duck class implements SimpleQuack where as Wild Duck implements NoQuack. And why is it beneficial to use an interface to achieve this instead of defining the behavior in the inherited class like one would normally do.


Why use properties that don't do any validation or other processes?

Suppose I have a property in a class as in the following:  class testclass {  public string Name {get; set;} public void dosomething(){//...}  }   There is no functional difference between this format and the following:  class testclass {  public string name; public void dosomething(){//...}  }   Both name fields can be set to anything including an empty string and both can retrieve just without any restrictions. So what is the use of the property semantics detailed above where there is no validation or other process in the get and set methods?  One use I see is that you can remove either the get or set method to make it write only or read only, respectively.  I don't know what other use this would serve.


Surjective Homomorphism between $\Bbb Z* \Bbb Z$ and $C_2*C_3$

In Paolo Aluffi's Algebra: Chapter 0, there is an exercise which asks     Prove that there is a surjective homomorphism (an epimorphism) from $\Bbb Z*\Bbb Z$ onto $C_2*C_3$, where $A*B$ is the coproduct of $A$ and $B$ in $\mathsf{Grp}$. One can think of $\Bbb Z*\Bbb Z$ as a group with two generators $x, y$ subject to no relations whatsoever.   I know that this question has been asked previously  and . But neither of them have correct answer that uses the machinery that has already been introduced. If you have not read the book, try not to use anything about coproducts in the answer other than the fact that they are initial objects in the category $C^{A,B}$.  Here's what I thought:  I know that since $\Bbb Z*\Bbb Z$ is an initial object, there is a unique morphism from $\Bbb Z*\Bbb Z$ onto $C_2*C_3$ in the category $C^{A,B}$. The only question is how to prove surjectivity of the morphism. We can construct morphisms from $\Bbb Z \to C_2 \text{ and } C_3$ that are surjective. Somehow we need to compose the two to form the required morphism.


Expected value of $\max\{X_1,\ldots,X_n\}$ where $X_i$ are iid uniform.

Let $X_i\sim\mathrm{Uniform}(0,\theta)$ be iid, what is $E[\max\{X_1,\ldots,X_n\}]$? Apparently the answer is $$\frac{n}{n+1}\theta,$$ but I do not see why?  It seems intuitive in that you would "expect" them to be spaced out evenly, hence the maximum would be $\frac{n}{n+1}$-of-the-way along the interval, but how can we prove this mathematically? I feel like it should be simple, but evidently $$E[\max\{X_1,\ldots,X_n\}]\neq\max\{E[X_1],\ldots,E[X_n]\}.$$ Thanks.


Every positve integer can be written uniquely as a product of a square and a square-free integer

I saw a question here with the same title but it was not answered properly, or I just couldn't extract the solution from the comments/answers. This is an exercise from Beachy and Blair: Abstract algebra. A positive integer is called $\textbf{square-free}$ if it is a product of distinct primes. Prove that every positive integer can be written uniquely as a product of a square and a square-free integer.  Here is my try:  Let $n\in\mathbb{N}^+$, by the Fundamental theorem of arithmetic we can write $n$ uniquely as  $$ n=p_1^{\alpha_1}\cdot p_2^{\alpha_2}\cdot\ldots\cdot p_n^{\alpha}. $$ with $p_n$ being distinct primes. Now $\alpha_i$ is either even or odd, lets rename the odd ones as $\beta_j$, then we have $$ \alpha_i=2k_i\qquad \beta_j=2l_j+1\qquad k_i,l_j\in\mathbb{Z}^+, \ \text{and} \ i+j=n. $$ Since multiplication is commutative we can rearrange the factors so all the even exponents come first so $$ n=p_1^{2k_1}\cdot p_2^{2k_2}\cdot\ldots\cdot p_i^{2k_i}\cdot p_{n-j+1}^{2l_{n-j+1}+1}\cdot p_{n-j+2}^{2l_{n-j+2}+1}\cdot \ldots\cdot p_n^{2l_n+1}= $$ $$ n=p_1^{2k_1}\cdot p_2^{2k_2}\cdot\ldots\cdot p_i^{2k_i}\cdot p_{n-j}^{2l_{n-j+1}}\cdot p_{n-j+1}\cdot p_{n-j+2}^{2l_{n-j+2}}\cdot p_{n-j+2}\cdot \ldots\cdot p_n^{2l_n}\cdot p_{n}. $$ Again by commutativity we can arrange so all the factors with exponent "$1$" get to the end of the expression so  $$ n=p_1^{2k_1}\cdot p_2^{2k_2}\cdot\ldots\cdot p_i^{2k_i}\cdot p_{n-j+1}^{2l_{n-j+1}}\cdot p_{n-j+2}^{2l_{n-j+2}}\cdot \ldots\cdot p_n^{2l_n}\cdot p_{n-j+1}\cdot p_{n-j+2}\cdot\ldots\cdot p_{n}. $$ finally $$ n=\underbrace{(p_1^{k_1}\cdot p_2^{k_2}\cdot\ldots\cdot p_i^{k_i}\cdot p_{n-j+1}^{l_{n-j+1}}\cdot p_{n-j+2}^{l_{n-j+2}}\cdot \ldots\cdot p_n^{l_n})^2}_{a^2}\cdot \underbrace{p_{n-j+1}\cdot p_{n-j+2}\cdot\ldots\cdot p_{n}}_{b}. $$ And we are done since this factorisation was unique from the beginning. Now one of my problems is that this doesn't look too nice. In my head it looks simpler ("bringing down" the ones from odd exponents) but the final product looks like a mess. Is there any easier way to describe this? (maybe I could have renamed the primes with odd exponents as $q$?) I mean if it is correct at all. And I have a further question, can I get any HINTS how to do this by induction? Thank you in advance!


While developing a C++ application, I had to use a 3rd party library which produced a huge amount of warnings related with a harmless #pragma directive being used.  ../File.hpp:1: warning: ignoring #pragma ident In file included from ../File2.hpp:47,                  from ../File3.hpp:57,                  from File4.h:49,   Is it possible to disable this kind of warnings, when using the GNU C++ compiler?


What's Python good practice for importing and offering optional features?

I'm writing a piece of software over on github. It's basically a tray icon with some extra features. I want to provide a working piece of code without actually having to make the user install what are essentially dependencies for optional features and I don't actually want to import things I'm not going to use so I thought code like this would be "good solution":  ---- IN LOADING FUNCTION ---- features = []  for path in sys.path:        if os.path.exists(os.path.join(path, 'pynotify')):               features.append('pynotify')        if os.path.exists(os.path.join(path, 'gnomekeyring.so')):               features.append('gnome-keyring')  #user dialog to ask for stuff #notifications available, do you want them enabled? dlg = ConfigDialog(features)  if not dlg.get_notifications():     features.remove('pynotify')   service_start(features ...)  ---- SOMEWHERE ELSE ------  def service_start(features, other_config):          if 'pynotify' in features:                import pynotify                #use pynotify...   There are some issues however. If a user formats his machine and installs the newest version of his OS and redeploys this application, features suddenly disappear without warning. The solution is to present this on the configuration window:  if 'pynotify' in features:     #gtk checkbox else:     #gtk label reading "Get pynotify and enjoy notification pop ups!"   But if this is say, a mac, how do I know I'm not sending the user on a wild goose chase looking for a dependency they can never fill?  The second problem is the:  if os.path.exists(os.path.join(path, 'gnomekeyring.so')):   issue. Can I be sure that the file is always called gnomekeyring.so across all the linux distros?  How do other people test these features? The problem with the basic  try:     import pynotify except:     pynotify = disabled   is that the code is global, these might be littered around and even if the user doesn't want pynotify....it's loaded anyway.  So what do people think is the best way to solve this problem?


How can I dynamically populate a query with a List / Array of items in SQL WHERE IN

I have a List<Long> matchingLongs = new Arraylist(); that I would like to pass to an SQL statement :    WHERE Id IN (matchingLongs);     How can I dynamically populate the Longs into the query?    If I would print to console it should look like :    WHERE Id IN (1223, 9834, 3, 924, 88778, 65652165223, 34, 8723738793287);     Thank you all.


Getting an error when I run my Java code [if statement]

My if statement (the one holding all the others) is running as false and I don't understand what I'm doing wrong. Here's a portion of my code. I really appreciate any help I can get as this is a school assignment   import java.util.Scanner;  public class StatesOfWater {    public static void main( String[]args )    {      Scanner water = new Scanner(System.in);       System.out.println("Enter a unit ( C for Celcius and F for Fahrenheit): ");      String unit = water.next();       System.out.println("Enter a temperature: ");      int temp = water.nextInt();      String c = "C";      String f = "F";        if (unit == c) //not assigning, equaliziing      {          if ( temp <= 0)          {              System.out.println("The state is solid.");          }           else if ( temp > 0 && temp < 100.00)          {              System.out.println("The state is liquid.");          }           else if (temp >= 100.0)          {              System.out.println("This is a gas");          }          else          {              System.out.println("error2?");             }     }     else      {         System.out.println("error?");     } } }   Using () instead of == does not compile as im using Java 7.


Right now, I am analyzing the prediction quality of a dynamic model that has variables with different units (e.g. $x_{1,t}$ is in meters, $x_{2,t}$ is in kilograms etc.). I have discovered a great tool called : $$ \frac{1}{n}\sum_{t=1}^n\left( \frac{\left| \hat x_{t,i} - x_{t,i} \right|}{\frac{1}{n-1}\sum_{\tau=2}^n \left| x_{\tau,i}-x_{\tau-1,i}\right|} \right) $$ where $i$ is index of variable.  The MASE is denoted as scale-free. I would be curious how to say that the error is large or small. My experience is that $MASE=3$ is not bad, but I would appreciate some more rigorous answer or reference.


In the wikipedia article on logarithms, I am clueless about the approach and motivation for the following computations done by Napier (and the mysterious appearance of Euler's number) in this . Please help me understand:       By repeated subtractions Napier   calculated $10^7(1 − 10^{−7})^L$ for L   ranging from 1 to 100. The result for   $L=100$ is approximately $0.99999 = 1  − 10^{-5}$. Napier then calculated the   products of these numbers with $10^7(1  − 10^{−5})^L$ for L from 1 to 50, and   did similarly with $0.9995 ≈ (1 −  10^{−5})^{20}$ and $0.99 ≈ 0.995^{20}$.   These computations, which occupied 20   years, allowed him to give, for any   number ''N'' from 5 to 10 million, the   number ''L'' that solves the equation      $$N=10^7 {(1-10^{-7})}^L$$      In modern notation, the relation to   natural logarithms is:      $$L = \log_{(1-10^{-7})} \!\left(  \frac{N}{10^7} \right) \approx 10^7  \log_{ \frac{1}{e}} \!\left(  \frac{N}{10^7} \right) = -10^7 \log_e  \!\left( \frac{N}{10^7} \right)$$      where the very close approximation   corresponds to the observation that      $${(1-10^{-7})}^{10^7} \approx  \frac{1}{e}. $$   I understand the computations, but I don't know what's going on.


I have verbose mode turned on always so I can see if a kernel panic or some error happens. After having it on for a few times, I started to notice that most of the boot was happening after the login. I can't show a picture as it is in boot, but the login screen loads before most of the OS. This is only after a cold boot but I can't seem to find any information on this. All I want is some information on this. EDIT: Basically, the machine starts to boot, the apple logo pops up, a small box of text scrolls down, where the rest of the monitor is not used, it shows the login screen, and after I type the password, the login screen goes away. now the whole screen is used and the rest of the machine boots up. EDIT 2: There is no firmware password. I have not locked the firmware.


I get error "Procedure tr_employee_tbl_forinsert Column name or number of supplied values does not match table definition" when I run the INSERT query below. What should I do?  create table employee_tbl ( EmpID int primary key, FirstName varchar(50), LastName varchar(50), Salary float, MobileNo varchar(15) )  create table employeeaudit_tbl ( EmpID int primary key, AuditData varchar(50) ) GO create trigger tr_employee_tbl_forinsert on employee_tbl for insert as begin         declare @EmpID int         select @EmpID = EmpID from inserted          insert into employeeaudit_tbl         values('New employee with EmpID = ' + CAST(@EmpID as nvarchar(5)) +'is added at ' + CAST(GETDATE() as nvarchar(50))) end GO


So I have this code here. It gets images from imgur and sets a Picturebox.  Code:  private async void getImage(string imgUrl)         {             var  request = WebRequest.Create(imgUrl);             using (var testing = request.GetResponse())             {                 using (var str =  testing.GetResponseStream())                 {                     addTablePic.Image = Image.FromStream(str);                 }             }         }   Answer (Edited)  I have found one of the answer on this .  private async void getImage(string imgUrl)         {             try             {                 var request = WebRequest.Create(imgUrl);                 var response = (HttpWebResponse)await Task.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, null);                  using (var testing = request.GetResponse())                 {                     using (var str = testing.GetResponseStream())                     {                         addTablePic.Image = Image.FromStream(str);                     }                 }             }catch(Exception ex)             {                 MessageBox.Show(ex.Message);             }         }   My question is how do I implement the async and await on WebRequest?


Is it possible to unbind or change the unicode input global shortcut?

I'm using Ubuntu 13.10, but I think the keyboard shortcut wasn't bound in 12.10, but could be wrong.  It's not in the shortcuts tab of keyboard settings. How can I change the Unicode input from Ctrl+Shift+U to other?


Why is Poisson regression used for count data?

I understand that for certain datasets such as voting it performs better. Why is Poisson regression used over ordinary linear regression or logistic regression? What is the mathematical motivation for it?


"Leader's Workshop" or "Leaders' Workshop"?

Leader's Workshop  or  Leaders' Workshop  Which is correct? A team of twenty leaders will be attending the workshop.


Can I use 'present perfect' when describing a historical event?

I learned that historical event like "Korean war broke out in 1950." should be described with past tense.        But when a past event influences present situation, could we use 'present perfect'?    Like this,'Korean war has broken out in 1950.' or 'Edison has invented the electric bulb.'  please, tell me.


Can frozen raw meat be defrosted and frozen again

A frozen joint of turkey was partly defrosted cut into 2 and the other half was re-frozen   Surely this is not safe


Strictly increasing function and its derivative

We have "$f'(x)>0$ in interval $I\implies f(x)$ strictly increasing in interval $I$". However, the converse is not true. A frequently cited example is the function $f(x)=x^3$, which is strictly increasing but $f'(0)=0$. Here comes my question:       What is the necessary and sufficient condition of $f'(x)$ to make $f(x)$ strictly increasing?    My guess is:       $f'(x)>0$ almost everywhere.     This is clearly a sufficient condition, as we can use Lebesgue integration and "drop the word 'almost'".    But is this a necessary condition? Is there a weaker condition? A full solution or a little hint will both be appreciated. Thank you in advance.


I read a book in the 60's when I was a child.  The narrator or main character arrives at an island, due to a shipwreck or some other disaster, and discovers a utopian society.  The families there have taken on the letters of the alphabet as their last names (Mr. A, Mrs. B, etc.)  There are only twenty families as there would be confusion if someone were named "U" (call out "Hey U," and everyone would react). I believe that is the reason why the narrator is told he cannot stay. Any ideas what book or short story this may be?


At which embassy should I apply for a Schengen visa when staying a few days in several countries?

I'm planning to go to Germany on Sept 6-8, then Netherlands on Sept 8-11 and exit Switzerland on Sept 11-14.  My question is:  Which embassy do I need to apply for the Schengen visa? The number of days are the same for Netherlands and Switzerland, but I'm planning to apply in Netherlands since it will be my second point of entry.


Irrationality proofs not by contradiction

Per now, I have basically come upon proofs of the irrationality of $\sqrt{2}$ (and so on) and the proof of the irrationality of $e$. However, both proofs were by contradiction.  When thinking about it, it seems like the definition of irrationality itself demands proofs by contradiction. An irrational number is a number that is not a rational number. It seems then that if we were to find direct irrationality proofs, this would rely on some equivalent definition of irrational numbers, not involving rational numbers themselves.   Are there any irrationality proofs not using contradiction?


Traveling to Brazil but with a layover in the US - two passports

I'm going to Brazil from Canada, but I have a layover in Chicago. When I do my check-in, do I use my Brazilian passport or my Canadian? Can I show the Canadian passport when going to Chicago and show the Brazilian passport when going to Brazil, since in Chicago I will have to check in my luggage again? I'm confused and I called the place bought my tickets from and they said I can't use 2 passports. Has anyone done it?


How to compile input files separately from the main file

I have a main document with lots of tikz pictures, which happens to be added from different directories within the main directory by using the 'input' and 'figure' commands. There are also some other files which make up the main file, like chapters and commentaries added the same way as the tikz pictures.   Since I want to modify some of those pictures and also files separately I don't want to compile the whole document every time I make a change because it takes a lot of time.    My question is whether by any chance there's some package or a workaround to manage this.  What I'm trying at the moment when I need to modify an input file is opening the file, pasting all the preamble of the main file in it, and then compiling it as an article class. The problem with this approach is that when I'm finished with it then I have to take out the preamble again and the other stuff I have added to compile (document class, begining and end document, etc). Also another drawback is that this process generates a lot of extra files.   Thanks for any help


How to make weekly newsletter FILTERED (e.g. C++ only) and otherwise customizable?

I see the link:     Get the weekly newsletter! In it, you'll get:   * The week's top questions and answers   * Important community announcements   * Questions that need answers   When I click it, it doesn't let me choose the tags/filters. I only want C, C++, valgrind, and some other tags (I don't want Java, Python, etc.).  How to subscribe for FILTERED weekly newsletter?  And how to make it not WEEKLY but bi-weekly or monthly?


I have a Dell XPS 13 9370 laptop with Ubuntu 18.04 and a Dell TB 16 Dock (Business Thunderbolt Dock). Since a few days ago, the laptop no longer works on the dock. When connected, it boots normally and I can log in. But about a minute after login, the laptop display and any externally connected monitor are turned off and the laptop seemingly goes to sleep. The power button light still indicates that it's on, and the keyboard backlight still goes on when I press a key (that's just a BIOS thing, I think), but the laptop otherwise doesn't react to keyboard input or mouse actions. The only thing that works is to press the power button for so long that the laptop powers off.  The same also happens immediately if I close the lid when the laptop is connected to the dock. (In the past, it would turn off the internal display and make the external monitor the primary screen, where the Gnome Shell Dash is shown, which is the desired behavior.)  A connection to the (powered) dock is enough to trigger this behavior -- it happens even if no devices are connected to the dock. Any suggestions what's wrong here and how to fix it?


Finding $$\sum^{\infty}_{n=1}\bigg[\bigg(\frac{(-1)^{n+1}}{n+1}\bigg)\bigg(\sum^{n}_{r=1}\frac{1}{r}\bigg)\bigg]$$   Try: Let $\displaystyle H_{n} =\sum^{n}_{r=1}\frac{1}{r},$ then series $\displaystyle \sum^{\infty}_{n=1}\frac{(-1)^{n+1}}{n+1}\cdot H_{n}=\frac{H_{1}}{2}-\frac{H_{2}}{3}+\frac{H_{3}}{4}\cdots\cdots$  could some help me to solve it, thanks


This is the output of update-grub :      Generating grub configuration file ... Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported. Found linux image: /boot/vmlinuz-4.2.0-18-generic Found initrd image: /boot/initrd.img-4.2.0-18-generic Found linux image: /boot/vmlinuz-4.2.0-16-generic Found initrd image: /boot/initrd.img-4.2.0-16-generic Found linux image: /boot/vmlinuz-3.19.0-32-generic Found initrd image: /boot/initrd.img-3.19.0-32-generic Found memtest86+ image: /boot/memtest86+.elf Found memtest86+ image: /boot/memtest86+.bin done   Should I do something to the grub configuration ?


What is the meaning of ${GZIP_BINDIR-'/bin'} in bash?

Can anyone explain what this command means?  PATH="${GZIP_BINDIR-'/bin'}:$PATH"; export PATH


List of Delphi data types with 'thread-safe' read/write operations?

Are 'boolean' variables thread-safe for reading and writing from any thread?  I've seen some newsgroup references to say that they are.  Are any other data types available?  (Enumerated types, short ints perhaps?)  It would be nice to have a list of all data types that can be safely read from any thread and another list that can also be safely written to in any thread without having to resort to various synchronization methods.


Open file or application as root from GUI

Is it possible to open a file or application as root from the GUI?  My ideal would be right-clicking on a file or an application and seeing an "Open as Root" choice in the context menu, after which I was asked for my root password.  Somewhat related to this is the ability to allow, for example, a save to take place where originally you had not opened the application as root (e.g., modifying a .conf file in /etc)


Words similar to 'either' and 'neither' for 3 items

Given two options, we can use 'either and 'neither' to show no preference.  Do you want to watch A or B Neither, I don't like either.  The only option I can see for more than two options is: 'any' and 'none'  Do you want to watch A, B, C ... ? None, I don't like any.  Actual Question: Is there, or has there ever been a word to show no preference for 3 options?  More Information Sometimes we have an extra, sometimes uncommon, option for a 3-type question. This question is searching for a similar option for "either"  How many times have you eaten sushi? Thrice    What is your phone number? Oh, seven, double five, treble zero    9 is triple 3


FFmpeg converting by a context menu entry

I want to create a right click/context menu entry named "Convert to MP4" available to every video file (or at least MKV, if every video file isn't possible), where it would do launch FFmpeg from a set location (let's say "C:\Users\Username\Documents\Programs\Portable\FFmpeg 20190916\bin") and do just that, create a MP4 version (lossless encoding / just change the container) of the input video file. The output file (MP4) should appear in the same folder with the input file. Ideally, I'd like to be able to do that with selecting (Ctrl+click) more than one file at a time too (but not necessarily every video file in the folder). I understand this should be possible by creating a bat file and then somehow integrating it in the context menu (with a "Send to" menu shortcut perhaps?). I don't really know CMD that well, though, and I am not sure what should I do so FFmpeg catches the specific file(s) and how to get the output file(s) in the same folder with the input. For starters, I've tried to adapt a bat file based on  answer to  to see, seeing If I can come up with a bat file that works (before I do the "context menu/registry" part), but, as I've said, I really don't know how to use cmd properly and it didn't work. I don't think my question is a duplicate of that question you've suggested, because mine deals with video rather than audio (I'm not saying it's much different in principle, I just don't know what to type instead of those audio codecs in order to adapt it) and most importantly, mine is about changing the container rather than converting so I would need different commands. So based on that answer and info found in  at Opensource.com, I've created bat files with commands such as: ffmpeg -i %1 copy "%~n1.mp4  ffmpeg -i "%1" "%1.mp4  ffmpeg -i "%1.mkv" "%1.mp4  ffmpeg -i input.mkv -c:av copy output.mp4  (I used the full pathname to FFmpeg, but omitted it here for ease of reading) then tried to drop an MKV file to them, but none work. I've already checked several questions in here dealing with cmd and FFmpeg but they weren't able to help so I'll appreciate any help given!


How do I include a common file in VBScript (similar to C #include)?

VBScript doesn't appear to have a way to include a common file of functions.  Is there a way to achieve this?


Confused by how "pass in by value" works

I'm new to Java and am confused by how "pass in by value" works.  int[] a;  public Constructor(int[] anArrayOfInt){      a = anArrayOfInt; }     does variable a point to the object passed into the constructor? Do changes to variable a reflect in the object that is passed into the constructor?


jQuery .click not working on dynamically loaded button

I'm a little stuck here. I have a dynamically loaded list, and it has a button in it. I have jQuery setup to handle the .click on it but nothing is happening. Here is some sample code.  HTML:

   jQuery/Javascript:  $(document).ready(function()      $.ajax({     url: 'showcart',     type: 'GET',     dataType: 'JSON',     success: function(products){       $.each(products, function(i, product){          var FORM = '<form action="#" method="POST" id="removeFromCart"><input type="hidden" name="id" value="'+ product.id +'"><button class="remove" type="button">x</button></form>';          $('#cart').append('
'+product.name+' : '+product.qty+'
');         $('#cart').append(FORM);       })     },     error: function(){       console.log('FAILURE LOADING PRODUCTS');     }   })    $('#productForm').submit(function(event){     event.preventDefault();     $.ajax({       type: 'POST',       url: 'addproduct',       data: $(this).serialize(),       success: function(addedProduct){         // var product = addedProduct.product;         var productName = addedProduct.product.name;         var productQty = addedProduct.qty;          var FORM = '<form action="#" method="POST" id="removeFromCart"><input type="hidden" name="id" value="'+ addedProduct.product.id +'"><button class="remove" type="button">x</button></form>';          console.log('Name:'+productName+' '+'Qty:'+productQty);         $('#cart').append('
'+productName+' : '+productQty+'
');         $('#cart').append(FORM);            $('#cart').empty();           $.ajax({           url: 'showcart',           type: 'GET',           dataType: 'JSON',           success: function(products){             $.each(products, function(i, product){                var FORM = '<form action="#" method="POST" id="removeFromCart"><input type="hidden" name="id" value="'+ product.id +'"><button class="remove" type="button">x</button></form>';                 $('#cart').append('
'+product.name+' : '+product.qty+'
');               $('#cart').append(FORM);             })           },           error: function(){             console.log('FAILURE LOADING PRODUCTS');           }         })       },       error: function(){         console.log('Failed to add or update product')       }     })    })    $(".remove").click(function(){     // event.preventDefault();     // var id = $(this).siblings("input[name='id']").val();     console.log('id');     // $.ajax({     //   type: 'POST',     //   url: 'removeproduct',     //   data: $(this).serialize(),     //   success: function(removedProduct){     //     // var product = addedProduct.product;     //     var productName = addedProduct.product.name;     //     var productId = addedProduct.product.id;     //     var productQty = addedProduct.qty;     //   },     //   error: function(){     //     console.log('Failed to remove product')     //   }     // })     // return false;   }) })


Primitive roots of the unity in $\mathbb C$

Let $\omega$ be a primitive $n-$th root of unity.  (i) Show that its powers $\omega^k$, for $k ∈ {1, \ldots, n}$, are all different;  (ii) Deduce that they are precisely all the $n-$th roots of unity.  I know that the powers have to be different as otherwise the order of $ω$ would be less than $n$ so $\omega$ wouldn't be a primitive $n-$th root of unity but I don't know how to prove this rigorously.


"Lyrics to a song" vs. "lyrics of a song"

I've seen both being used interchangeably. Are both valid? Is only one correct?        Lyrics to a song.     Lyrics of a song.


Proof that $\frac{1}{T}$ is the integrating factor for $dq$

Consider the first law of thermodynamics, $$ dU = dq +dw$$ simplfying, $$ dU + P_{\text{ext}} dV = dq$$ Now we can say that $ q $ is a function of $ U$ and $V$ $ dq(U,V) = dU + P_{\text{ext}} dV$  For a differential $dF(x,y) = A\, dx + B\, dy $ to be exact, $$ \frac{\partial A}{\partial y} = \frac{\partial B}{\partial x}$$ is a necessary  condition.  Clearly the  function $q(U,V)$ doesn't obey this definition, and hence, let us multiply both sides by an integrating factor $ \phi(U,V)$ such that the condition of exact differential is satisfied. $$  \phi(U,V) \, dq = \phi(U,V) \, dU + \phi(U,V) P_{\text{ext}} \, dV$$ For this to be exact, $$ \frac{ \partial \phi(U,V) P_{\text{ext}} }{\partial U} = \frac{\partial \phi(U,V) }{\partial V}$$ Which leads to: $$ \left( \frac{\partial P_{\text{ext}} }{ \partial U} \right)_V \phi + P_{\text{ext}}(\frac{\partial \phi}{\partial U})_V =(\frac{\partial  \phi}{\partial V})_U $$ Now, I'm not sure how to get a general solution for the above partial differential equation...  My real goal is to derive the expression for entropy at end and prove that $ \frac{1}{T}$ is the integrating factor but I'm a bit stuck. I've seen the proof that $ \frac{1}{T}$ is the integrating factor by people pointing to carnots theorem that the circulation of the differentials over a loop is zero but I wanted to derive it using differential equations. Now, I'm thinking of how I can include the assumption that the process is reversible because the entropy definition is written used $ dq_{\text{rev}}$; also maybe derive the entropy generation term. Any hints?


How to prove this inequality $ x + \frac{1}{x} \geq 2 $

I was asked to prove that:   $$x + \frac{1}{x}\geqslant 2$$  for all values of $ x > 0 $  I tried substituting random numbers into $x$ and I did get the answer greater than $2$. But I have a feeling that this is an unprofessional way of proving this. So how do I prove this inequality?


Projective and injective modules; direct sums and products

I need two counterexamples.  First, a direct sum of $R$-modules is projective iff each one is projective.  But I need an example to show that, “an arbitrary direct product of projective modules need not be a projective module.”  If I let $R= \mathbb Z$  then $\mathbb Z$ is a projective $R$-module, but the direct product $\mathbb Z \times \mathbb Z \times \cdots$ is not free, hence it is not a projective module. We have a theorem which says that every free module over a ring $R$ is projective. Am I correct?  Second, a direct product of $R$-modules is injective iff each one is injective  but I need an example to show that the direct sum of injective modules need not be injective.


Say you have an HTML page of input elements with JavaScript connected to the input elements. You have the ability to press the TAB key, which by default browser behavior will highlight select the input element. Pressing TAB key again will then highlight select the next input element that is declared in the source code.  My question is, in JavaScript, how can I check if a specified input element is currently highlight selected?  I have tried researching this on my own prior to this post, but didn't find anything.


Does a first generation iPod touch have the ability to download apps and use emojis?

I am getting a 1st gen iPod touch for a friend and I was wondering if you can download like apps and games on it and if it has emojis? It would help to get an answer before I buy it!


Does community user auto-protect old questions?

An  with lots of views was just bumped by a spam user. The post was spam-flagged and removed, and the question was .   Does this mean this  is ? Is there any other criteria for auto-protecting or does this happen when an answer on an old, popular (metrics?) question gets spam-flag-removed?  For what it's worth, I thought I saw a similar behaviour yesterday, but I was not sure.


How to find the square roots of a matrix?

Square root of a matrix A is not a unique matrix, generally.  How to find all the square roots of a matrix, in particular the following matrix B:  $$ \begin{bmatrix} 1 & 0 & 0 \\ 0 & -1 & 0 \\ 0 & 0 & -1 \end{bmatrix} $$  other than forming 9 equations in 9 variables as:  $$ \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} = \begin{bmatrix} 1 & 0 & 0 \\ 0 & -1 & 0 \\ 0 & 0 & -1 \end{bmatrix} $$  In particular, is there any square root of B that has all elements as real numbers.


Upgraded to Chrome 61.0.3163 via ppa on Ubuntu 16.04 but it won't launch because NSS out of date

I upgraded to Chrome 61.0.3163 via ppa on Ubuntu 16.04 but it won't launch because NSS out of date. Launching Chrome in terminal gives:  NSS >= 3.26 is required. Please upgrade to the latest NSS, and if you still get this error, contact your distribution maintainer.   Running   sudo apt-get install libnss3   gives  libnss3 is already the newest version (2:3.21-1ubuntu4)   Should I try to get a newer version of libnss that's not in the repository? I downgraded my version of Chrome for now.  Edit:  apt-cache policy libnss3 libnss3:   Installed: 2:3.21-1ubuntu4   Candidate: 2:3.21-1ubuntu4   Version table:  *** 2:3.21-1ubuntu4 500         500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages         100 /var/lib/dpkg/status  cat /etc/apt/sources.list # deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted  # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://us.archive.ubuntu.com/ubuntu/ xenial main restricted # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial main restricted  ## Major bug fix updates produced after the final release of the ## distribution. # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates main restricted  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## universe WILL NOT receive any review or updates from the Ubuntu security ## team. deb http://us.archive.ubuntu.com/ubuntu/ xenial universe # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial universe # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates universe  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu  ## team, and may not be under a free licence. Please satisfy yourself as to  ## your rights to use the software. Also, please note that software in  ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://us.archive.ubuntu.com/ubuntu/ xenial multiverse # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial multiverse # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates multiverse  ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. # deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse  ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. deb http://archive.canonical.com/ubuntu xenial partner deb-src http://archive.canonical.com/ubuntu xenial partner  # deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted # deb-src http://security.ubuntu.com/ubuntu xenial-security universe # deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse


Wand ownership in the Harry Potter universe

First of all, this answer is related, but not equal to, .  In the final acts of the HP story, we learn that wand ownership plays a great part. If a wizard uses a wand that does not belong to him, his power is greatly diminished.  Now, a wand belongs to a certain wizard and will change allegiances if the wizard is killed or disarmed by another (for example, Draco disarming Dumbledore). However, we also find out that a wand will change allegiances even when it was not directly involved in the fight that causes it to shift. For example, when Harry disarmed Draco, Draco did not have the elder wand in hand. Still, because Draco was the owner of the elder wand, and Harry defeated him, Harry became the new owner.    Now, this leads me to believe that the rule is      If a wizard is disarmed by another wizard, the second wizard becomes the owner of the first wizard's wands.   This, however, is horrible. This rule means that whenever I disarm someone, I am now the owner of his wand, and there is no way for him to get his wand back without me losing my wand. My wand and his are now locked to have the same owner for eternity. Even worse, if I'm a defence against the dark arts teacher and I am teaching a class to perform the Expelliamus spell, there are bound to be some succesful spells cast, and therefore half of my students will lose ownership of their wands. Probably, after a couple of fights, there will be a handful of students who own 10 or more wands each!  Am I missing some rule here? How is it possible in the HP universe that anyone still has ownership of their wand?


(1) List<?> myList = new ArrayList<?>();  (2) ArrayList<?> myList = new ArrayList<?>();   I understand that with (1), implementations of the List interface can be swapped.  It seems that (1) is typically used in an application regardless of need (myself I always use this).    I am wondering if anyone uses (2)?    Also, how often (and can I please get an example) does the situation actually require using (1) over (2) (i.e. where (2) wouldn't suffice..aside coding to interfaces and best practices etc.)


So at the end of Age of Ultron, during the post credit scene, we see Thanos grab a gauntlet (not sure from where) and says "Fine, I'll do it myself" or something like that, he puts on the gauntlet, end scene.  But we know that the gauntlet he is currently using was from Eitri's forge on Nidavellir.  Is that the same gauntlet?  I think that maybe it was the "fake" one that Hela knocks over.  Or could it be that the other gauntlet was lost, stolen, or fake?


I have long lost hope to get the hard numbers on how willpower works, just kinda accepted that it grows with levels and you lose it when critically wounded, and each class gains slightly different amounts.  But today I noticed I have two snipers that are identical in every way, except that one of them   has 2 more kills has 2 more willpower   (I have not yet researched Iron Will, and both ladies are drafted the usual way, not as mission rewards).  Really? Does every kill actually increases willpower by 1? If not, what's going on here?!  Screenshots:


I've tried, but I can't solve the question. Please help me prove that:  $\operatorname{Aut}(\mathbb Z_n)$ is isomorphic to  $U_n$.


I have been wondering what it means when people use "respectively" in, before, and after sentences. For example:     We are looking for a babysitter to pick up and supervise our kids ages   6 and 3, respectively, on Monday and Friday.   I don't know if this person used it correctly, but if they did what does it mean? If they didn't use it properly what would be the proper usage?  Thanks in advance.


How to make each monitor act as a separate desktop instead of all changing together?

So I have my laptop hooked up with two external monitors. Let's say I have a browser, code editor, and terminal open in each screen. If on my laptop I change from my code editor to the browser, it changes all screens to the browser. The behavior I want, is for it to change the app only on the current screen, and leave the other two screens as they were. Is there a way to do this?


How many rectangles can be obtained by joining four of the $12$ vertices of a $12$-sided regular polygon?

What is the number of rectangles that can be obtained by joining four of the 12 vertices of a 12-sided regular polygon?  The thing that I've tried is to find out at what intervals should I connect to vertices of the polygon so that a rectangle can be formed. But that didn't seem to help at all .


The density function for a random variable X is given in terms of a constant c.  Find the value of c.  What is the corresponding distribution function?  Sketch both the density and the distribution functions. Finally, find the probabilities.  5.1 $f(x)=0$ for $x<0$ and $f(x)=\frac{c}{(x+1)^4}$ for $0<x$  $P(X>4)$ $P(X<2)$ $P(1\le\ X<3)$  I get c=3 by taking the integral, and then I am a little confused as to why  $F(x)=1-\frac{1}{(x+1)^3}$  Is that because in solving for c, I ended up with $1=\frac{c}{3(x+1)^3}$, so substituting c in I get $1=\frac{1}{(x+1)^3}$?  And, then  $P(X>4)=1-P(X\le\ 4)$ $=1-(1-{1}{(1+4)^3})$ $=1/125$  $P(X<2)=1-{1}{(1+2)^3}$ $=26/27$  I guess I am a little confused about what F(x) and f(x) actually MEAN? And thus that leads to my confusion about what the differences between > and < and greater than or equal to are, etc etc in terms of the equations. The ones above I solved by comparing to the book but I still don't understand what they mean really.  So as a result, I don't really get how to solve $P(1\le\ X<3)$.


how to create booth wallpaper 118 in by 98 in and 300 dpi file in photoshop

W-3m W-2.5m Resolution-300 dpi how to create booth wallpaper in this size I have already try but show me screch disk are full and I have already change screch disk then my all disk are full.   please give me answare and solve my problem


Suppose $n$ is composite. Consider a prime $q$ that is a factor of $n$ and let $(q^k) || n$. Then $q$ does not divide $$\dbinom{n}{q}$$ Why it is correct?


We deployed our new Linux/Exim/Spamassassin mail server on Friday (always a good idea to deploy the day before a long weekend when no admins are around). The load has been hovering around 1.3 on the 15-minute average.  The machine is responsive, and mails are delivered in reasonable time. Can we assume that this is acceptable?  How is a certain amount of load deemed acceptable or not acceptable? What metrics are used?


Derivation of odds ratios from logit equation parameters?

I have been trying to understand how this interpretation works. For this I have used the article "Interpreting the Parameters of Loglinear Models" from Alba, but  I am really stuck.   I his article he derives the logit equations for a polytomous dependent variable (Intermarriage). So fa so good. The coefficients obtained are as follows:     but then Alba calculated the Odds ratios for Intermarriage (different versus same ancestry), by ancestry, cohort, generation and gender. I cannot figure out how he obtained the highlighted values. Anyone can explain/derive the values highlighted in red please?    I am sure there must be some easy explanation, but I wasn't able to figure it our.


What I need to do is randomly shuffle an array of 25 numbers  int[] arr = Enumerable.Range(0, 24).ToArray();   So that it still has all the numbers from 0 to 24 but in a random order. What would be the simplest way to do it?  @edit;  namespace WindowsFormsApp1 {     public partial class Form1 : Form     {         Random rnd = new Random();         int[] arr = Enumerable.Range(0, 24).OrderBy(c => rnd.Next()).ToArray();          public Form1()         {             InitializeComponent();         }     } }


How can I calculate total points of a user on his answers upvotes?

My employer want to calculate the total points of a user on his answers only. He don't believe in the reputation earned through questions!  If technically impossible, just the sum of upvotes and best answer points sum of his answer. (without edit, chosen best)