Access local server via WAN FQDN and Draytek router/firewall

I'm experiencing problems accessing a local server in my LAN via it's internet address. Let me explain. I have a local server, on IP 192.168.1.15, and it's serving http (port 80) (All my computers/servers in my LAN having addresses in the  192.168.1.0/24 range). When I access this server from a computer in the LAN via , everything works. This server is accessible from the internet via NAT (e.g. ). This is working as well, no problem there. However, when I try to access this server from my LAN via this address (), I'm unable to access it. When I check the firewall log, it's giving this entry:  [FILTER][Block][LAN/RT/VPN->WAN, 1:23:18 ][@S:R=13:1, 82.84.24.33:58741->192.168.1.15:80][TCP][HLen=20, TLen=52, Flag=S, Seq=1765099532, Ack=0, Win=64240]   Where 82.84.24.33 is my fixed WAN IP. And this is making no sense for me:  LAN/RT/VPN->WAN / 82.84.24.33:58741->192.168.1.15:80     It looks like the firewall thinks that the 82.84.24.33 is LAN and 192.168.1.15 is WAN.... And another strange thing, there are rules in the firewall to allow traffic LAN->WAN for port 80 (http)... Even in the other direction as well (WAN->LAN). Only when I set the default rule in the firewall to 'allow' in stead of 'block' it's working, but that's obviously no option. Thanks!


I came across this in java, I know its a static nested class but why create an instance of 'static'. Isn't the whole idea of 'static' to use it without an instance? I understand the concept of inner classes, but why (and frankly how is it possible to) create an 'instance' of a 'static' member at all ?   Why this:  1- OuterClass.StaticNestedClass nestedObject = new OuterClass.StaticNestedClass(); 2- nestedObject.aNestedClassMethod();   and not this:  1- OuterClass outerInstance=new OuterClass(); 2- outerInstance.StaticNestedClass.aNestedClassMethod();


How to handle unhandled exception in .NET web services

I need to handle all the exceptions globally in .NET 2.0 web service (ASMX), i tried using Application_Error event in global.asax, but it's not fired in web services case, it works fine for web based applications.  Any suggestions???


correctly declaring the main() function in ANSI C

The C standard say:     The function called at program startup   is named main. The implementation   declares no prototype for this   function. It shall be defined with a   return type of int and with no   parameters:  int main(void) { /* ... */ }       or with two parameters (referred to   here as argc and argv, though any   names may be used, as they are local   to the function in which they are   declared):  int main(int argc, char *argv[]) { /* ... */ }       or equivalent or in some other   implementation-defined manner.   However, Kernighan & Ritchie in their second edition (the canonical ANSI C) bible just use:  main() {   /* taram pampam ... */    return 0; }   Who is right? Does it have to do with function without return value automatic assume to be returning int in C?


Need to add new picklist values to the existing custom picklist field using apex?

Can anyone suggest me how to add new value to the existing custom picklist using apex?


Until a few days ago, I only ever used Texstudio (on windows) to create LaTeX documents, relying entirely on the build and compile button to sort everything out for me. I've been trying to understand how one might compile a latex document without an IDE, and have discovered that this is achieved simply by typing pdflatex filename.tex into a command line, provided that the appropriate binaries folder is in included in the "PATH" environment variable. However, citations and bibtex/biber require that you run bibtex and pdflatex in the order latex>bibtex>latex>latex. So I hypothesised that this is exactly what the build part of the Texstudio button "build and view" does. But this doesn't seem to be the case. This is my messagelog after pressing build and compile on my template.tex file:  Process started: bibtex.exe "template"  This is BibTeX, Version 0.99d (MiKTeX 2.9) The top-level auxiliary file: template.aux The style file: biblatex.bst Database file #1: template-blx.bib Database file #2: testbib.bib Biblatex version: 3.0  Process exited normally      Process started: pdflatex.exe -synctex=1 -interaction=nonstopmode "template".tex  Process exited normally   So Texstudio seemingly runs bibtex followed by pdflatex. I tried doing this manually via the command prompt but bibtex responded "I couldn't open the file template.aux", which is a file created only after having run pdflatex at least once. This implies that Texstudio is running pdflatex before running bibtex even though it doesn't mention so in the message log. I have not changed Texstudio settings to add anything extra to the compilation order. So I'm stumped as to what's going on. Thanks for any help.


When should I delete my unanswered questions?

Last week I wrote a , and I noticed that no one has answered it nor comment it (it only has one comment). Maybe my question is too broad, too complex or too strange, I am not sure, because it's my first question on the site and my first time making a game, so I'm not sure how to explain it. But the important thing is that I posted the question 8 days ago, and I still doesn't have an answer. Also, I don't know how much time it usually could take, but I never saw a question that didn't have an answer in less than 4 days (without being downvoted or closed), so I am starting thinking that maybe I shall delete my own question. Shall I delete it? Actually the question doesn't have any answer, and maybe it would never have one, so it's just trash. It takes space in the site, making the search of other questions on the site slightly more difficult and it doesn't provide useful information. Does it have any positive use on Stack Exchange?


Using integral test to show $ \sum_{n=3}^{\infty} {1 \over {n\cdot \log{n} \cdot \log{\log {n}}}} $ diverge

I want to use the integral test to show that $ \sum_{n=3}^{\infty} {1 \over {n\cdot \log{n} \cdot \log{\log {n}}}} $ diverges.  First, I let $ f(x) = {1 \over {x\cdot \log{x} \cdot \log{\log {x}}}} $  I have learned that in order to use the Integral test, $f(x)$ must be continuous, positive, and decreasing at the interval $ [1,\infty) $  However, when I drew the graph of $f(x)$ using an online graphing calculator, the graph only seemed to be satisfying the three conditions of the Integral test when $ x \geq 10 $, or the interval $ [10, \infty) $  Doesn't that mean that I cannot use the Integral test? Other than that, I was also confused on why the series starts from n = 3 when the series is also defined a value at n = 2. (although negative, like at n = 3)


How does the second law of thermodynamics forbid the possibility of perpetual machine of the second kind?

Fermi in his lecture asserts:     The second law of thermodynamics rules out the possibility of constructing a perpetuum mobile of the second kind.   So, this means there can be no machine which just transforms all the heat energy gained by cooling surrounding bodies into mechanical work.  But how does actually the Second Law prohibit this?   The hot reservoir provides heat energy to the system. Does it cause a decrease in entropy of the universe(system + hot reservoir)? How? In order to receive heat wouldn't the system have to be cooler than the reservoir? If so, then entropy increases as the heat energy gets expelled from the reservoir at a higher temperature than the temperature the system receives the heat energy. Is it so?  I'm not getting how the Second Law nullifies the existence of this machine. Could anyone please explain how the Law prohibits the perpetual machine of the second kind?


A sequence converges to $x$ if and only if every subsequence converges to $x$

I have a proposition on the book  which states the following:  Let $x_n$ be a sequence in $\Bbb R$ and let x $\in \Bbb R$. Then $x_n \to x$ iff every subsequence of $x_n$ converges to $x$.  Could you please help me on the proof of this? I can't see any way to approach it.


How to kill all processes owned by `user` on Centos 7?

I read in an online flash card that the command is:  pkill -u bob $(pgrep -u bob)   However, I think this is wrong. I think it's saying:     Kill all the processed owned by bob, and 4572\n4600   Because:  [bob@localhost ~]$ pgrep -u bob 4572 4600   Also, it gives an error:  [bob@localhost ~]$ pkill -u bob $(pgrep -u bob) pkill: only one pattern can be provided Try `pkill --help' for more information.   Which makes sense because you can't have newlines in usernames, right?  I think the command should only be:  pkill -u bob   To "kill all processes owned by bob"  While the command:  pgreg -u bob    Gives "all processes owned by bob"  I'm wondering:   Am I uses the right commands as intended? Is my analysis of the incorrect way accurate?


deleting folders with spaces in their names using xargs

Why can't xargs delete directories with spaces in their names, and how to fix that?  76 find . -type d |xargs  rm -rf  77 rm -rf fire\ hydrant/  78 rm -rf wine\ glass/  79 rm -rf tennis\ racket/  80 rm -rf traffic\ light/  81 rm -rf parking\ meter/  82 rm -rf teddy\ bear/  83 rm -rf sports\ ball/  84 rm -rf cell\ phone/  85 rm -rf stop\ sign/  86 rm -rf dining\ table/  87 rm -rf potted\ plant/


How to disable all permissions and sudo password requirements?

I don't want it to ever complain about permissions or ask for sudo password ever again. Is there any way to do this?


Find coefficient of $x^{n}$ in $\frac{1}{(1-x)^3(1+x)^2}$

I want to find a general expression for $x^{n}$ in $\frac{1}{(1-x)^3(1+x)^2}$.   I have tried to use partial fraction but that got complicated and I got stuck.   Any help would be appreciated.  Note: I would need a closed form expression


How can I install downloaded 'netbeans' in Ubuntu 12.04?

I am new to ubuntu. I've just downloaded 'netbeans ide 7.3' for linux and 'jdk 7'. but don't know how to install them. please tell me proper step by step procedure on installing these application.


A bijection between $\mathbb{N}$ and $\mathbb{P}(\mathbb{N})$?

I would like to ask for a little help or a hint about a set theory exercise i am stuck in.     Let $f: \mathbb{N}\rightarrow \mathbb{P}(\mathbb{N})$, $\mathbb{P}(\mathbb{N})$ is the power set of the natural numbers, be a map. Consider the subset $A\subset \mathbb{N}$ defined by $A=\{ m\in \mathbb{N} \mid  m\notin f(m)\}$.   Assume that there is an integer $r\in \mathbb{N}$ such that $f(r)=A$.      (1) What happens if $r\in A$?   Here I think I get to a contradiction by the definition, because $r\in A=\left \{ r\in \mathbb{N}\mid r\notin f(r) \right \}$ but $f(r)=A$ by definition. So it's not surjective, thus there is no bijection.     (2) What happens if $r\notin A$?    Here I get again a contradiction, the same way like in the first question.     Is there a bijection between $\mathbb{N}$ and $\mathbb{P}(\mathbb{N})$?   I think the answer is no, because the function is not surjective.  Are my ideas correct? If you have a remark, I would be very happy if you can share it here. Thank you in advance! Have a nice day :)


What happens to spells cast from Nightveil Specter's ability?

If I managed to exile a  from a library with  and I play the rift, does it go to the owner's graveyard or does it stay in exile?


In LyX, how can I set a float that contain figure so that the caption is under the figure? By default the caption is always on the left side of figure.


How do I prove this using question using Cauchy-Schwarz inequality?

$$(a_1 + a_2 + · · · + a_n)( 1/a_1 +1/a_2+ · · · +1/a_n) ≥ n^2$$  My TA mentioned he solved this using Cauchy Schwartz inequality, but I don't see how. All I've managed to do is make a summation of $1$, $n$ times, which ends up being $n ≥ n^2$.


I have some difficulty to understand the schematics for the following anemometer:   I have confusion at 5 points.  Here is the schematics:     In the manual it states: “Avoid a short circuit between the wind direction signal line and either the excitation or reference lines. Although there is a 1K ohm current limiting resistor in series with the wiper for protection, damage to the potentiometer may occur if a short circuit condition exists” But when I look at the circuit diagram it seems to me like there is no problem if wind direction signal line and the reference line shorts. It seems like there is danger if wind direction signal line via the 10K potentiometer comes to dead spot and shorts with the excitation line. Do you think there is a problem if wind direction signal line the 10K potentiometer comes to dead spot and shorts with the reference line? What is the use for the capacitor C1 at the circuit diagram which is connected in parallel with ac signal output for the wind speed? What is the use for D6 and D7? Could you give an example when are they beneficial? In the manual it states: It is important to note that, while the sensor mechanically rotates through 360°, the full scale wind direction signal from the signal conditioning occurs at 355°. The signal conditioning electronics must be adjusted accordingly. For example, in a circuit where 0 to 1.000 VDC represents 0° to 360°, the output must be adjusted for 0.986 VDC when the instrument is at 355°. (355°/360° X 1.000 volts = 0.986 volts). Is total dead spot 5° form only one side or it is at  both sides as 2,5°+2,5°? In the manual it states: “To prevent false readings, signal conditioning electronics should clamp the signal to excitation or reference level when this occurs.” Is that about the dead spot part in case of short circuit? Does a zener clamp work for that purpose at the signal output?


What is the origin and thought process behind the tradition of hats?

Winter Bash is always a lot of fun and makes people trek across sites and participate in communities they are not usually a part of, but how did they originate? What was the thought process behind introducing this tradition?


Layer added did not move in ArcGIS Desktop?

I have done the step from my previous question at  and it looks great when the layer did match all together.  It almost the same problem. The problem is, why the layer that I add into table of contents did not move into any single place that I edit in the properties?  It only stick into one place only. I have try many ways to change the location of the layer added.    The red point is my layer added after I add the Bing Maps from Arcgis 10. Then I click the right click button < properties < Coordinate system.         I'm still learning the basics.


Security problem as using same apple id on my mother and my phone bcz of which all imsgs and calls are going to her also

I have 2 iphones one is with my mother and one is with me but apple id on both the phones is same which is creating problm for me as my imessages and facetime calls are going to her also so how can i make my stuff secure and stop my calls and message on going on her iphone????


I have burned the ISO image onto a disc, restarted my computer booting from the disc, gone through the "install ubuntu" option to run inside Windows 8. And a while later it tells me to remove the installation media, close the try and press enter.  Then it reboots my laptop, then takes me into Windows 8. Ubuntu literally did nothing!  I'm confused. And I'm stressed out. I've been at this for the pass 5 hours, FIVE hours!  I have a USB available if it's easier to install like that.


iPhone 7 screen is frozen on the shutdown screen

my screen is frozen on the slide to power off screen and it won't let me get out of it. I've tried holding down the home button and the lock button for a long time and it hasn't worked. I've also tried using siri and haven't gotten anywhere. I plugged in my phone as well and that didn't do anything either. I have an iPhone 7


Allow voting "Vote to not close" from the question without being in a review

I just reached the 3k rep limit required for close votes and have started exploring the vote-to-close UI that's opened up to me, and I have a request.  The review queue has a Do Not Close button, but when I click the close link under a question that has close votes (i.e. it shows close (1)), there isn't an option for me to vote against closing the question. I came across a question that had a vote to close it as not a question, but it had just been updated with code and more details and was no longer a candidate for closing. However, I couldn't cast a vote to not close it from the question itself. When I clicked on close, it brought up the usual voting UI, and "Do Not Close" was not an option.  TL;DR, do this:   Open a question in the close votes review queue Note the Do Not Close button Click the question title to go to it Click the close (n) link under the question (assuming it hasn't already been closed) Notice the lack of an equivalent "Do Not Close" option   Could a "Do Not Close" option be added to the close button popup for questions that already have close votes, that way the review interface isn't the only place a "Do Not Close" vote can be cast?  Edit: Okay, so 5 3 "Do Not Close" votes kicks it out of the review queue, it doesn't have "no effect" as suggested in the comments. (See , in which the  was just updated a few minutes ago to say 3 DNC votes.) I still don't see why the same DNC option can't be available from the question.  Basically, I guess I would like some rationale behind this bullet point from :     Only accessible from the review queue (so rather difficult to target a specific question). Yes, this is very much by-design.


How to show given space is not simply connected?

Let $X=\{p,q,r,s\}$ with  topology induced by basis $\{p\}$,$\{r\}$,$\{p,q,r\}$, $\{p,r,s\}$. Then $X$ is not simply connected.   My Attempt:  $\{p\}$ is open set and $\{q\}$ is closed set.  Define $\phi:[0,1]\to X$, where  $$\phi(x)=\begin{cases} q & x=0,1,\\ p & x\in (0,1). \end{cases}.$$  $\phi$ is a continuous loop. But how to show it is not homotopic to constant?  Any Help will be appreciated.


How do I delete my recent google profile picture after I've changed it?

Every time you change your profile picture on Google it saves it, and I would like to know how to delete recent Google profile pictures.


Consider a heat equation  $\frac{\partial u(t,x)}{\partial t} = a^2 \frac{\partial^2u(t,x)}{\partial^2x},$ for $x \in (-\infty,+\infty), t\in(0,+\infty)$, $u(0,x)=0$ for $x \in (-\infty,+\infty)$ I know that there exists a unique solution in class of bounded functions. This solution in general case can be found by using Fourier transform. But there also exists unbounded solution. So, my question is how can I find it?


Is there an easy way to replace duplicate files with hardlinks?

I'm looking for an easy way (a command or series of commands, probably involving find) to find duplicate files in two directories, and replace the files in one directory with hardlinks of the files in the other directory.  Here's the situation: This is a file server which multiple people store audio files on, each user having their own folder. Sometimes multiple people have copies of the exact same audio files. Right now, these are duplicates. I'd like to make it so they're hardlinks, to save hard drive space.


Why is there no space after omega (and what can I do after it)

I put omegas in my text as needed using a command:  \newcommand{\ohm}{$\Omega$ }   Then I needed other symbols so I included package gensymb. But when I do, \ohm is already defined. So I tried using the one defined in the library.  It does not add a space afterward, not sure why. My \kohm and \Mohm work fine.  I'm not sure whether I should be overriding the \ohm command.  What is the best approach to solve this problem?  MWE:  \documentclass[12pt]{book} \usepackage{gensymb} \newcommand{\fahren}{\degree F} %\newcommand{\cels}{\degree C} %\newcommand{\ohm}{$\Omega$ } \newcommand{\kohm}{k$\Omega$ } \newcommand{\Mohm}{M$\Omega$ }  \begin{document} test \ohm test \kohm test \Mohm I measure temperature in \fahren \end{document}   I do not want to have to add braces or a backslash after the command: \ohm{} or \ohm\  The \kohm command works as I want it to, inserting a space afterward because it is an equation. I suppose I can define a \ohm command that is exactly the same as \kohm but then I would have to replace every one of the \ohm commands in multiple documents.


A function satisfies the equation $f(x+y) = f(x) f(y)$. Show that $f(x)$ is differentiable at all $x$, and determine its $f'(x)$ in terms of $f(x)$.

If $f(x)$ is differentiable at $x=0, \space f'(0) = c \space$ where $\space c \space$ is a constant and $\space f(x) \space$ is not equals to $0$. Someone please help me. Im stuck on this question. I've no idea where to even start.


Uninstalling an Application on Windows 10 from a deleted partition

Here is the situation, I foolishly decided to install several apps to a D: drive rather than the C: drive in my Windows 10 install. I thought this would help me get up and running faster in the event of having to reinstall. Very few apps actually worked this way, so I decided to cut my losses and go back to the way it was. Silly me, I didn't uninstall the app from the D: drive first. I just deleted the partition. This has caused a problem, mostly with my Anti-Virus software Malwarebytes. The program is still listed under programs via control panel and the settings menu. Uninstalling it from the settings menu tells me the path does not exist, and the control panel tells me I do not have permission. When running the Windows uninstall troubleshooter from Microsoft I have to manually key in the product ID for the Malwarebytes. It runs and says the program is gone. It did not work though, even after a restart the program remains. I attempted to install the program again, but it simply tries to force me to install to a D: drive that no longer exists. I cannot change the file path. Having encountered this before, I tried to clean the Registry. This did not work. It seems this is not a common enough issue to yield good results on my Google searches, as running the troubleshooter seems to fix it for most people. I am on Windows 10 Pro Version 20H2 OS build    19042.985 Experience  Windows Feature Experience Pack 120.2212.2020.0


Typing "i" in search box opens inbox on mobile

I find myself unable to type the letter i in the search box here or meta.SE in the mobile view, because as soon as I do, the "supercollider" inbox opens.  I have keyboard shortcuts enabled in preferences, which is probably the reason I see this here as well as on e.g.  and  (though not on ).  I use the Grazing browser on an iPhone 5. I can repro this behavior on the default browser Safari as well.


showing group $G$ is cyclic if every number $m$ that divides $(G:1)$, there are atmost $m$ elements such that ...

The following problem is from  book     Let $G$ be a finite Abelian group. If $G$ has at most $m$ elements of order dividing $m$ for each divisor of $m$ of $(G:1)$, show that $G$ is cyclic.   I do not understand the notation $(G:1)$. Also I would highly appreciate any hints (need not solve the problem as it coincides with my assignment) for solving the problem.


What's the difference between a POST and a PUT HTTP REQUEST?

They both seem to be sending data to the server inside the body, so what makes them different?


Problem 5, sec. 13 in Munkres' Topology, 2nd ed.: How to prove the assertion if $\mathscr{A}$ is a subbasis?

Show that if $\mathscr{A}$ is a basis for a topology on $X$, then the topology generated by $\mathscr{A}$ equals the intersection of all topologies on $X$ that contain $\mathscr{A}$.   This is what I've managed. However, the following stumps me:   Prove the same if $\mathscr{A}$ is a subbasis.   That is, how to show that the topology generated by $\mathscr{A}$ as a subbasis is the same as the intersection of all topologies on $X$ that contain $\mathscr{A}$?   Let $\mathscr{T}$ be the topology that consists of all unions of finite intersections of sets in $\mathscr{A}$, and let $\mathscr{T}^\prime$ be the topology that is the intersection of all topologies that contain $\mathscr{A}$.   Now $\mathscr{A}$ is a collection of subsets of $X$ whose union is all of $X$, and each set $A \in \mathscr{A}$ is in both $\mathscr{T}$ and $\mathscr{T}^\prime$.   Am I right so far?   And if so, then what next?


Generator expressions vs. list comprehensions

When should you use generator expressions and when should you use list comprehensions in Python?  # Generator expression (x*2 for x in range(256))  # List comprehension [x*2 for x in range(256)]


My script is not running on boot in a vagrant box under Ubuntu.  My script looks like this -  #!/bin/bash # /etc/init.d/mailcatcher ### BEGIN INIT INFO # Provides: scriptname # Required-Start: $remote_fs $syslog # Required-Stop: $remote_fs $syslog # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: Start daemon at boot time # Description: Enable service provided by daemon. ### END INIT INFO mailcatcher --http-ip 192.168.50.10   My permissions on the file look like this -  -rwxr-xr-x 1 root root 352 Apr 30 09:59 mailcatcher.sh   I run the command -  sudo update-rc.d "mailcatcher.sh" defaults   If I run the script manually, it works and starts mailcatcher. If I reboot the computer, the mailcatcher daemon does not start. Am I missing something?


Where on the file system are SMS messages stored?

Where in the file system are SMS messages stored?  I'm using ES File Explorer to browse around but can't seem to find this - is it on the phone or the SD, and where?  I have an HTC Wildfire but I would imagine it doesn't vary hugely from vendor to vendor (although I am an iOS developer who knows little about Android).


Why does it (apparently) make a difference whether I pass null as an argument directly, or pass an Object that I assigned the value null?  Object testVal = null; test.foo(testVal);    // dispatched to foo(Object) // test.foo(null);    // compilation problem -> "The method foo(String) is ambiguous"     public void foo(String arg) { // More-specific     System.out.println("foo(String)"); }  public void foo(Object arg) { // Generic     System.out.println("foo(Object)"); }   In other words, why is the (commented-out) second call to foo(...) not dispatched to foo(Object)?  Update: I use Java 1.6. I could compile Hemal's code without problems, but mine still doesn't compile. The only difference I see is that Hemal's methods are static while mine are not. But I really don't see why this should make a difference...?  Update 2: Solved. I had another method foo(Runnable) in my class, so the dispatcher couldn't unambiguously select the single most specific method. (See my comment in Hemal's second answer.) Thanks everyone for your help.


.on("click",...) not working on objects created with the same on click function

since I am new to JS / jQuery it is probably a obvious problem (but no exception thrown). I read that I can't use .onclick so i tried this approach with .on("click"...)   I try to build a table that adds new lines under the clicked line. This should also work for the newly created lines.  My html:

Stuff1	Stuff	Stuff	Stuff	Stuff

Stuff2	Stuff	Stuff	Stuff	Stuff

Stuff3	Stuff	Stuff	Stuff	Stuff

Stuff4	Stuff	Stuff	Stuff	Stuff

   My JS:        Thanks for your help! :)


I have a marshmallow device, it has custom ROM, and is obviously rooted.  I am looking for a way to access the app data, cache of other apps. As I am rooted, I guess this is possible.  I tried searching and found that Titanium Backup can access databases and cache files.  I am only able to save databases but not all the cache files.  So, is there any app to get all the cache files saved?


How to download .doc files using python in windows?

I am downloading a .doc file using python in windows. But the downloaded file is not in readable form.  import urllib url = 'https://ums.lpu.in/assignments/Teacher/16920_CA3.doc' data = urllib.urlopen(url) with open('file1.doc','w') as f:    # wb also gives the same result     f.write(data.read())   I am getting the file using this method but the file can't be read. I tried many ways but none of them seems to be working.


This is the question: Find the sum of $$\frac1 9+\frac2{9^2}+\frac3{9^3}+\ldots +\frac n{9^n}+\ldots$$ What I did was convert the whole equation to $$\frac{1\cdot 9^{n-1}+2\cdot 9^{n-2}+3\cdot 9^{n-3}+\ldots +n}{9^n}$$ I have no clue about what to do next. I would probably think that you would have to identify the sequence but I don't know how to get there from this.


Why is my compiler expecting a NullPointerException when it shouldn't?

I have created a FloatingActionButton object outside methods without giving it any value. Inside the method fabInitializer, I give it a value by referencing it to tag in the XML file.  When I want to use a method of class's object I've created, Android Studio says:      object.method() may produce a java null pointer exception.   The program runs fine.  If the object value is null it should produce that message, but it is not. How can I fix this?  public void fabInitializer() {     mFab = (FloatingActionButton) findViewById(R.id.fab);     mFab.setOnClickListener(this);  }


Getting information on a machine's hardware in Linux

How can I check what hardware I have? (With BIOS version etc.)


Which should I use on my DB? - Clustered Index or Non Clustered Index or Both

I just need advice on how I am going to optimize my database.  Date ---- Time ---- Area ---- Block ---- Data1 ---- Data2 ---- Data3 ---- DataN   I have that format of tables on my database. Each tables has 30-days of records with hundred thousands of records each data. Uploading of data to database is every morning. The data of yesterday will be uploaded.  The most common queries to run is grouped by Date or Date and Area or Date and Area and Block. Now, in order to make queries faster, I found out using indexes. I used indexes before. But that was when I am using a primary key. In this table, I didn't use primary key because it is totally unnecessary.   Now, I am really confused on how I am going to optimize this. Based on  on Column Considerations part, clustered index is not a good choice on Columns that undergo frequent changes. I am really confused.  Please help me if I need to use clustered index here or just non clustered or both.


$K$ finite field, $P'(X) = 0$ then P is reductible

In this exercise I've shown first that if we have $P'(X)=0$ then the $Car K$ different $ 0$. Now they are specifing that if$ K$ is a finite field than $P$ is reductible. I've been searching for hours, tried to write the derivative of $P$ but I get nothing intersting.  Any Hint ?   Thanks for reading,


Accuracy of A Equivalence about Absolutely Convex Sets

I remember I’ve seen a theorem but I’m not sure about remembering it truthfully or not. I cannot find this equivalence in anywhere. That is the reason of my doubt. Is it true or not? If it is true how should I show it via using definitions below? Could someone share exact theorem and proof or its link? If there is a mistake please fix me. Thanks a lot  Let $X$ be a vector space over $\mathcal F$ field (it is real or complex numbers) and $A \subseteq X$ $A$ is absolutely convex if and only if A is convex and balanced  Let $\lambda , \beta \in \mathcal F$ and $x,y \in A$  If $|\lambda| + |\beta| \le 1$ such that $\lambda x+ \beta y \in A$ then $A$ is an absolutely convex set  If $\lambda x \in A$ such that $|\lambda| \le 1$ then A is balanced set  If $\lambda x + (1- \lambda )y \in A$ such that $|\lambda| \in [0,1] $ then A is convex set


Finding out whether two matrices are similar?

$\mathbf{B = P^{^-1} A P} \iff$ ($\mathbf{B}$ is similar to $\mathbf{A}$)  I'm a little confused about matrix similarity. Let's say we have the following matrix $A$:   \begin{bmatrix}2&5\\4&1\end{bmatrix}  Its eigenvalues are $6$ and $-3$. Respective eigenvectors $\left<(5,4)\right>, \left<(-1,1)\right>$.  How do I find out whether its similar to another matrix (B)?  Let's say matrix $B$:  \begin{bmatrix}4&5\\1&4\end{bmatrix}  Trying to actually find the regular $P$ so that the equation would be satisfied seems like way too much calculating.  My idea is to try and diagonalize both of them - and if I end up with same eigenvalues on the diagonal (in whatever order), then they are both similar? (using the transitive property, since similarity is an equivalence).  Thank you in advance.


Compiling (C++): prod/coretech/hub/compression/lz4_compressor.os prod/coretech/hub/compression/lz4_compressor.cc:31:17: fatal error: lz4.h: No such file or directory  #include "lz4.h"                  ^ compilation terminated. scons: *** [prod/coretech/hub/compression/lz4_compressor.os] Error 1 scons: building terminated because of errors.


Koma-Script | Book Class | Title Page: Author's Name Before Book Title

I want the author's name to appear first on the title page.  Screenshot    MWE  \documentclass{scrbook}  \begin{document}  \title{My Title} \subtitle{My Subtitle} \author{John Doe} \date{}  \maketitle        \end{document}


The C programming language has a preprocessor, which has #ifdef #endif macros that allow to preprocess a source code file before the compilation process.   I am looking for something similar. What I actually want is being able to pass some variable straight to the compiler like so (it would compile text enabling some variable):  pdflatex mydocument.tex -DSOME_VARIABLE   Is there anything I could use? Again, all I want is conditional compiling and being able to pass some variable from the command line.


Why declare an interface inside an interface?

This is a simplified version of java.util.Map  public interface Map {     interface Entry{         int getKey();     }      void clear(); }   My question is why it is done that way?   How the inner interface should be implemented? Can I just implement the inner one?


Clustering coordinates into groups of size n

I have a series of coordinates. I know that I can cluster these using some of the basic methods like k-means or hierarchical clustering. I can also easily find out which is the closest neighbor to each coordinate.  However, how do I split the data into clusters, so that each cluster is exactly of size n, and that each coordinate only belongs to one cluster?   How could I do this in R, for example on this data and Euclidean distances:  data(iris) plot(iris$Sepal.Length, iris$Sepal.Width)


Object should not be affected by one light source

I want it, so my object is affected by light but not by the light from one light source.


Review of a proof for De Moivre's theorem using mathematical induction

The following is a rigorous proof of De Moivre's theorem by means of mathematical induction. The theorem put simply is that:  Any complex number, $z = a+bi$, on a cartesian plane can be expressed in polar form, where $a=r\cos\theta$ and $b=r\sin\theta$ and $r$ is the absolute distance from the origin to the point $z$. In light of this, the expression for the complex number $z$ in polar form is $z=r(\cos\theta+i\sin\theta)$ In order to find the $n^{th}$ power of $z$, the following rule applies: $$\displaystyle z^n=(r(\cos\theta+i\sin\theta))^n=r^n(\cos n\theta+i\sin n\theta)$$ where $n\in\mathbb N$ (I have confined $n$ to the natural numbers given that I intend on using mathematical induction to prove the theorem.  Base step: We must prove that what is stated is true for $n=1$, hence $$z^1=r^1(\cos 1\cdot\theta+i\sin1\cdot \theta)$$ $$=r(\cos\theta+i\sin\theta)$$ which is true. Next we assume it is true for $n=k$, and therefore proceed to the inductive step. Inductive step: When calculating $z^{n+1}$, it's the same as calculating $z^nz$, hence $$z^{n+1}=(r^n(\cos n\theta + i\sin n\theta))(r(\cos \theta+i\sin \theta))$$ $$=r^nr(\cos n\theta+i\sin n\theta)(\cos\theta +i\sin \theta)$$ $$=r^{n+1}(\cos n\theta\cdot\cos\theta+\cos n\theta \cdot i\sin\theta+i\sin n\theta\cdot\cos\theta+i^2\sin n\theta\cdot\sin\theta)$$ from here, $i^2=-1$, and therefore $+i^2\sin n\theta\cdot\sin\theta$ becomes $-\sin n\theta\cdot\sin\theta$. In addition to this, the following trigonometric identities will be used: $$\sin(n\theta + \theta) = \sin n\theta\cdot\cos\theta+\cos n\theta\cdot\sin\theta$$ $$or$$ $$k\sin(n \theta+\theta)=k\sin n \theta\cdot\cos \theta + \cos n\theta\cdot k\sin\theta$$ $$and$$ $$\cos(n \theta + \theta)=\cos n\theta\cdot\cos\theta-\sin n\theta\cdot\sin\theta$$ by using these, the original equation has now become $$=r^{n+1}(\cos(n \theta + \theta) + i\sin(n \theta + \theta))$$ then, after factoring out $\theta$, the theorem becomes $$=r^{n+1}(\cos((n+1)\theta)+i\sin((n+1)\theta))$$ which completes the proof. Question: is this proof correct all the way through? Or have I missed any conditions? If all is well in the case of this proof, could somebody aid me in proving it for $\{n|n\in\mathbb R,n\geq1\}$


Solve $6x\equiv 2\pmod 8$  This is the method that I used: $$6x\equiv 2\pmod 8\implies12x\equiv 4\pmod 8\implies3x\equiv 1\pmod 8\implies9x\equiv 3\pmod 8$$ $$\implies x\equiv 3\pmod 8$$ However, the solution to the question gives $2$ solutions: $$x\equiv 3\pmod 8 ~\text{or}~x\equiv 7\pmod 8$$ How did they get the second solution? Forgive me for such a basic question, but I have only just started learning Number Theory and modular Arithmetic. Also, I'm not quite sure if I was allowed to divide by $4$ in the $3$rd stage. Thanks for your help.


Have I missed anything? user1 is not in the sudoers file

I've created a user on a server where there was only root as:  # adduser user1   with a password. Then  # su - user1   And then:  $ apt-get update E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied) E: Unable to lock directory /var/lib/apt/lists/ E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root? user1@my_server:~$ sudo apt-get update [sudo] password for user1: user1 is not in the sudoers file.  This incident will be reported.   I believe I've missed something such as add some privileges or something like that.  How to fix that?


How to delete an app permanently with its history

I have an issue similar to one posted here before:   What can I do to fix it?


How to replace array key with particular name

How can I replace my array key to particular name  Array   (     [0] => 0     [1] => 1     [2] => 3     [3] => 4     [4] => 5   )


From an :     An Integrated Textile Park (ITP) being developed at Edlapadu on Guntur-Chennai National Highway is expected to give the much-needed fillip to textile industry in Andhra Pradesh.   I do not understand the structure of this sentence, specifically the "being" part. To my knowledge "being" should be used only for Present and Past Continuous. I've googled around, but nothing came up.


How do I scale an object proportionally using numbers on the scale panel?

Everytime I change the X axis to 2' it literally only does the x axis and I was wondering if there was a way I could do this proportionally


Which files I need to delete from the system of a rooted device to delete completely the recovery mode, and in which folder I can find them? Ty


My 9 month old baby is pretty much addicted to his pacifier, and I kind of worry about if I should set some limits to pacifier use - like, he is starting to say a couple of recognizable words, but isn't the pacifier in the way? My first daughter never gave a pacifier a try, it just wasn't her thing. I started giving a pacifier to this one for sleep after a couple of week. Now when he does not have it, he puts anything he can get his hands on in his mouth, so I end up handing it to him. I thought of teething but it's not just when new teeth are showing up, he's been going for everything with his mouth for practically forever. On the other hand when he has his pacifier he actually looks at his toys and bangs them and interacts with them instead on trying to find a way to suck on them. Any advice? I'll admit I'm also confused because his sister was so different...


How can I generate data with a prespecified correlation matrix?

I’m trying to generate correlated random sequence with mean = $0$, variance = $1$, correlation coefficient = $0.8$. In the code below, I use s1 & s2 as the standard deviations, and m1 & m2 as the means.   p = 0.8  u = randn(1, n) v = randn(1, n) x = s1 * u + m1 y = s2 * (p * u + sqrt(1 - p^2) * v) + m2   This gives me the correct corrcoef() of 0.8 between x and y. My question is how can I generate a series means if I want z that is also correlated with y (with the same correlation $r=0.8$), but not with x. Is there a particular formula I need to know? I found  but couldn't understand it.


Is there a performance hit if we use a loop instead of recursion or vice versa in algorithms where both can serve the same purpose? Eg: Check if the given string is a palindrome. I have seen many programmers using recursion as a means to show off when a simple iteration algorithm can fit the bill. Does the compiler play a vital role in deciding what to use?


For which formats are Cycles materials completely and accurately exported?

I'd like to export my scene to one or more of the file formats listed in the File → Export menu:  .3ds, .dae, .obj, and so on. Which, if any, of these formats records all the details of Cycles materials – all the types of shaders, RGB curve nodes, all the texture types, and so on?  If I make a complicated material in the Node Editor, will the visual appearance of the rendered object be properly conveyed to someone using 3D Studio or Wavefront? I'm not worried about meshes or most other things, just materials.  Lacking any of the software which would normally use any of the exportable formats, I have no way to check by direct experiment.  Even if it did work – and even if Blender can re-load an exported file and the scene looks okay – I can't be sure if I just got lucky and unwittingly avoided some tricky feature.


Booting from GPT disk on old MBR computer

I have pretty old (~8 years) Supermicro server, which just got 4T new disk (actually it may be even bigger, because we are considering update to 5T or maybe even RAID 12T).  I'm trying to install some modern OS, which can boot both from MBR or from EFI. However if I go MBR, this limits my total available space by 4T (2x2T msdos partition size), if I set GPT partition, BIOS doesn't recognize boot sector and EFI of course.  Is there any way to boot EFI OS over MBR and don't lose space on the disk? In other words, is it possible to boot EFI from GPT partition on the MBR computer?  I know that GPT can work in hybrid mode, so I thought to set there GRUB and from GRUB, boot the main OS over EFI..... But I'm not sure that grub can boot EFI. Also it looks very kludgy....


{Proof Check} Let $D$ be a Euclidean Domain with Euclidean norm $\mu$. Then $\mu(1) = \mu(u) \iff u$ is a unit.

Please point out any mistakes and flaws in my arguments. Thanks! Hint: $\forall a\in D\setminus{0}$, $\mu(1) \leq \mu(a)$ (Proof. $\mu(1) \leq \mu(1a) = \mu(a)$) Proof. ($\implies$) Suppose $\mu(1) = \mu(u)$ s.t. $u$ is a non-unit in $D$. $u = 0$ is not possible since $\mu(0)$ is undefined, so $u \neq 0$. Then $\exists q,r \in D$ s.t. $1 = uq + r$. If $r=0$, then $u$ is a unit, a contradiction. If $\mu(r) < \mu(u)$, then $\mu(r)< \mu(1)$, contradicting the hint. Thus $u$ is a unit. ($\impliedby$) Let $u$ be a unit in $D$. From the hint, $\mu(1) \leq \mu(u)$. Also $\mu(u) \leq \mu(uu^{-1}) = \mu(1)$. Thus $\mu(1) = \mu(u)$.


When I type command like sudo su,su or sudo -i, I get the space to enter the password. But the problem is when I type the password it is not entered in the terminal. I tried pressing Enter then typing the password but no help. In GUI based password dialogs (like unlocking Ubuntu while booting) it is working fine. Is there any alternative for a root access terminal in Ubuntu LTS 18.04.3?


Interpretation Born-Von Karman boundary conditions

The cyclic  says that if we consider a one dimensional lattice with length $L$, and if $\psi(x,t)$ is the wavefunction of an electron in this lattice, then we can say that $\psi(x+L,t) = \psi(x,t)$ for every $x$. Applying this boundary condition leads to correct solutions for $\psi$. This boundary condition can also be generalized to three dimensional lattices and can be applied when working with phonons instead of electrons.  I wonder if there is a reasoning why these boundary conditions can be applied. They appear to me as elegant boundary conditions, but I don't see any reason why these conditions could be applied. Can we derive the Von Karman boundary conditions or are they just an experimental result?


The  has a designation of STM on the lens. What does this mean? What are the advantages of having it and does it replace an older technology?  We have a  that usually covers these questions but this is not yet addressed in it.


Prove that $ AB = BA $ if and only if $ \det\begin{bmatrix} b & a - c \\ e & d - f \\ \end{bmatrix} = 0 $

Question: Let $\mathbb{F}$ a commutative field and $ a,b,c,d,e,f\in\mathbb{F} $ be scalars and suppose that $ A $ and $ B $ are the following matrices:  $$ A = \begin{bmatrix} a & b \\ 0 & c \\ \end{bmatrix} $$ and $$ B = \begin{bmatrix} d & e \\ 0 & f \\ \end{bmatrix} $$   Prove that $ AB = BA $ if and only if  $ \det\begin{pmatrix} \begin{bmatrix} b & a - c \\ e & d - f \\ \end{bmatrix} \end{pmatrix} = 0 $   My steps:  $$ \det\begin{pmatrix} \begin{bmatrix} b & a - c \\ e & d - f \\ \end{bmatrix} \end{pmatrix} = 0 $$ $$ b(d - f) - e(a - c) = 0 $$ $$ bd - bf - ea + ec = 0 $$ $$ bd - bf = ea - ec $$ At this point I considered that one of the following things must be true for the solution to hold: $$ b = e = 0 $$ which would mean that $ A $ and $ B $ are diagonal matrices meaning $ AB = BA $   Another condition for the solution to hold would be $$ b = e, a = d, f = c $$ which would mean that $ A = B $ hence $ AB = BA $ must be true.  Would this be the right approach to the problem or is there a point that I am missing?


How to differenciate instanciated variables from others?

Here is my code:          Piece grille[][] = new Piece[9][9];         grille[0][0] = new Piece(1,joueur1,0);         grille[8][0] = new Piece(1,joueur2,0);         grille[0][8] = new Piece(1,joueur2,0);         grille[8][8] = new Piece(1,joueur1,0);         grille[0][1] = new Piece(3,joueur2,1);         grille[1][0] = new Piece(3,joueur2,1);         grille[1][1] = new Piece(3,joueur2,1);         grille[7][0] = new Piece(3,joueur1,2);         grille[7][1] = new Piece(3,joueur1,2);         grille[8][1] = new Piece(3,joueur1,2);         grille[7][7] = new Piece(3,joueur2,3);         grille[7][8] = new Piece(3,joueur2,3);         grille[8][7] = new Piece(3,joueur2,3);         grille[0][7] = new Piece(3,joueur1,4);         grille[1][7] = new Piece(3,joueur1,4);         grille[1][8] = new Piece(3,joueur1,4);         grille[3][4] = new Piece(2,joueur1,0);         grille[5][4] = new Piece(2,joueur2,0);          for(int i=0; i<9; i++){             for(int j=0;j<9;j++){                 if(grille[i][j].joueur == null)                     grille[i][j] = new Piece(0, null,0); //0 correspond a case vide             }         }   My instance variables in Piece are :  public int type;     public Joueur joueur; public int param;   It seems that the error comes from this: grille[i][j].joueur == null  I get this error:     Exception in thread "main" java.lang.NullPointerException at Citadella.(Citadella.java:35) at Partie.main(Partie.java:8)


What decisions and factors should be considered to determine when to use ligatures? Only in headings? Only in body? Purely by eye?  I ask because about seven people looked over a poster design and liked it. One noticed, "hey Ryan, the f and i in identification are so close the dot is missing." Now, after being pointed out, others think its an error as well. I had to explain what a ligature was, and that it wasn't a mistake.  The font is Futura:    When, if ever, should someone use ligatures?


How to create a view of hierarchical taxonomies and each taxonomy lists all its nodes?  Item1 --node1 --node2 Item1.1 --node3 Item1.2 --node4 Item2 Item2.1 --node5


Many times people share their email to another user in the chat room, for personal purposes and even for community purposes, for instance: translation coordination (all this happens at least in Stack Overflow en Español chat room).  I would like to have a option that allow me to send my email address to a specific user, something like Share email with....   This would be useful in order to prevent my email being recorded in the room or published via RSS.   It would be a private way to share my real private email address that Stack Overflow already has in my profile.     It is different of the duplicate-candidate question because: I just want send my email, not private messages. I understand that private messages is never going to be implemented here and that is the main reason why I am asking this feature: to send just the email without need to send a private message that Stack Overflow already knows.


Confusion regarding one formulation of the Axiom of Choice.

One formulation of the Axiom of Choice is:     The Cartesian product of non-empty sets is always non-empty.   Cartesian product is defined as making "every possible pair" between elements of two sets. The implication is that through some aritrarily selected algorithm, we can select each element one-by-one, and pair it with another element (from another set). Does the Axiom of Choice imply that without assuming such an axiom, no such algorithm can exist? What if the elements are ordered? If I have a linearly ordered set, and I state that I my method of selection of elements is I will move from the lowest element to the highest element, am I still using the Axiom of Choice somehow? Is choosing even the lowest element in a set an exercise of the Axiom of Choice?  Thanks


Meaning of @classmethod and @staticmethod for beginner?

Could someone explain to me the meaning of @classmethod and @staticmethod in python? I need to know the difference and the meaning.   As far as I understand, @classmethod tells a class that it's a method which should be inherited into subclasses, or... something. However, what's the point of that? Why not just define the class method without adding @classmethod or @staticmethod or any @ definitions?  tl;dr: when should I use them, why should I use them, and how should I use them?


How to get hard disk information on linux terminal?

We can get CPU information using lscpu command, is there any command to get hard disk information on Linux terminal, in a similar way?


Laptop boots with blank screen but HDMI Monitor is working

English translation:  Hello all, can you help me fix this problem.  I installed Ubuntu on my notebook for the first time. My laptop is an ACER ASPIRE 5336 I installed Ubuntu while connected to an external HDMI monitor because my laptop does not work and you see black screen. How can  I fix this?     Original Spanish:  Problema mi portatil con pantalla negra pero HDMI monitor si funciona  Hola a todos, podéis ayudarme como solucionar el problema.  Mi portátil, queremos instalar ubuntu por primera vez.  Mi portátil tiene marca es ACER y su modelo es ASPIRE 5336 He instalado ubuntu desde HDMI monitor porque mi portátil no funciona y se ve pantalla negra.  Como se soluciona? Por favor  Mil gracias.


How to construct Hash function in python3?

In many cryptographic protocols design like  one, I have seen the statement 'Choose a Hash function for example: \begin{align} h&:  \{0,1\}^*\times\mathbb G\to\mathbb Z_q^*\\ h_2&:  \{0,1\}^*\times\{0,1\}^*\times\mathbb G\to\mathbb Z_q^*\\ \end{align} in which it takes as input a binary string and a random element of some group and outputs an element of multiplicative group of prime field. How could I construct such a hash function?


Could we "invent" a number $h$ such that $h = {{1}\over{0}}$, similarly to the way we "invented" $i=\sqrt{-1}$?

$\sqrt{-1}$ was completely undefined in the world before complex numbers. So we came up with $i$.   $1\over0$ is completely undefined in today's world; is there a reason we haven't come up with a new unit to define it? Is it even possible, or would it create logical inconsistencies?  What would be the effect on modern math if we did so?


What are good out of the box alternative geocoding solutions to Esri's services?

Esri's  will retire at the end of the year, what are good GIS services that can replace the North American and US Streets geocoders?  I have totally excluded Esri's replacement, the  as it is a subscription service.


This example wanted to show if $k$ is a field, $X$ the affine line with a double point as in Ex 2.3.6, then X is not separated.  It argued that $X$(product over $k$)$X$ is affine plane with double axes and four origins. It is not closed because all four origins are in the closure of the diagonal.So the diagonal is not a closed immersion.  But I don't know how to display the product scheme explicitly. Although it looks natural, usually the underlying space of the product scheme may not be the product of the corresponding topological spaces.  I tried to construct it from the method in arbitrary product schemes but got messy. Can anyone help me with that?  Another question is if $ k$ is assumed to be algebraically closed here?


Can I compare non-nested models with AIC?

Is it formally correct to compare two separate models with different independent variables?  For instance in R a pseudo code would be something like:  AIC( lm( y ~ X ) )  vs.  AIC( lm( y ~ W ) )  (X and W cannot feature in the same model as for instance lm( y ~ X*W ) )


Is it better to type hint classes or type hint interfaces?  If I type hint a class I could basically pass in every class with the exact same name, but maybe not with the same methods the class I'm injecting it into needs to work properly.  While with interfaces I can pass in any class (of any name) as long as the type hinted interface has been implemented.  What are the actual pros and cons of type hinting classes and interfaces?


Transform multiple row values to 1 row values

I have the following table   Id | dwCode| PRNo | ----------------------- 1    DW001    PR001 2    DW001    PR002   And I need the following result:   dwCode| PRNo | ----------------------- DW001    PR001,PR002   Is there any short way to transform the data like this using MS SQL Server 2005?


The user who first created a tag wiki is treated as owner for suggested edits

was declined by the user who created the tag wiki excerpt, who doesn't yet have the reputation to be a trusted user. (The site is still in beta, and the reputation necessary to be a trusted user is 4000.)        Should the user who first proposed a tag wiki, or a tag wiki excerpt be the one who can unilaterally decide about a proposed edit for a tag wiki? The user who first proposed it isn't necessarily the one who knows if the tag's purpose can be better described with different words, nor does that user necessarily know if the tag has been lately used differently from how it was first used. Since a tag wiki is different from other posts, there should be an exception to the rule "the author of a post can unilaterally decide about any edits."  The paradox is then that the creator of a tag wiki still needs two users to approve their suggested edit. That's what happened in .        The funny fact is that in the revisions for the tag wiki, or tag excerpt (as in the screenshot), the tag wiki/excerpt is said to be created from the Community user.        This bug is  definitely .


Why do some people on Stack Exchange seem to only denigrate users on here?

As useful as forums can be for people learning coding/languages, why do some people feel the need to denigrate others on here who are not at the same level as they are?  Do they not remember what it's like to be just starting out coding, or just learning a new language?  Why do they feel the need to put down beginners?  Why do they have to doubt that the person asking the question has truly looked for an answer before posting it on here?  I have gotten lots of help on here for things that I most definitely have tried researching via Google.  A lot of times it may come down to my not knowing the specific terms or wording to lead me to the answer I need, so I come on here.  And most of the times, people have been very helpful.  But there are also a number of times where people just felt the need to be smug and superior and I don't understand it.  As if they were born with it?  Do they not remember what it was like to be starting out, or to suddenly not really be sure how to word what you are looking for?  (sorry, but just so very frustrating sometimes)


How can I force two figures to appear on the same page, each with their own figure number and caption?

I have two figures that I want to force to appear on the same page.  What is the best way to accomplish this?  Here is my MWE: \documentclass{book} \usepackage[semibold,tt=false]{libertine} \usepackage{graphicx} \usepackage{lipsum}  \begin{document}  \lipsum[1-4]  \begin{figure}   \centering   \includegraphics[width=0.9\textwidth]{example-image-a}   \caption{First figure}\label{fig:first} \end{figure}  \lipsum[5-8]  \begin{figure}   \centering   \includegraphics[width=0.9\textwidth]{example-image-b}   \caption{Second figure}\label{fig:second} \end{figure}  \lipsum[9-12]  \end{document}   to place both images in the same figure environment, but honestly, that doesn't seem very elegant. So I thought I'd ask the experts here!


Show this inequality $\frac{n}{a_1 - a_0} + \frac{n - 1}{a_2 - a_1} + \cdots + \frac{1}{a_n - a_{n-1}} \ge \sum_{k=1}^n \frac{k^2}{a_k}$

For $a_1, \ldots , a_n \in \mathbb{R}, a_1 < a_2 < \cdots <a_n$ and $a_i \ne 0$, show that  $\dfrac{n}{a_1 - a_0} + \dfrac{n - 1}{a_2 - a_1} + \cdots + \dfrac{1}{a_n - a_{n-1}} \ge \sum_{k=1}^n \dfrac{k^2}{a_k}$  where $a_0 = 0$.  I tried mathematical induction but not able to solve (not able to simplify n = k +1) expression.  The inequality mentioned in the chapters are   Cauchy-Schwarz Inequality  Weierstrass's Inequality  Tchebychev's Inequality  I think we need to use Tchebychev's Inequality to prove this but I'm not able to solve this.


Positive rationals satisfying: $a^2+a^2=c^2$?

If there are none why not?  Thanks in advance.


ubuntu 16.04 can't input password in command line mode(console mode)

In Ubuntu 16.04 I enter control + ALT + F1 into the command line mode(console mode) and after I type my server name, I can't input anything in "Password:" where it goes immediately to the next line. By the way, I have tried to reboot the computer, change the keyboard and switch to the F1 to F6. However, they didn't work. As shown in the picture, as soon as I type the name of my server in the line of "xxx login:" and press the key "Enter", the cursor jumps to the next line of "Password:".


Make phone calls from computer through land line

I have an ADSL line with 20Mbit/s downstream and 1Mbit/s upstream.  Is it possible to make voice phone calls in Linux/Windows 7 using my own land line?   I don't want a VOIP software (like skype), nor an external service which requires an account. Just make a call as I make using a phone device, but using a computer connected to landline through a router.   Linux solution is preferred over Windows 7, if it's possible.   I've been searching how to do it, but I just found VOIP solutions (which requires an external service) or using a 56Kbps modem, but nothing about ADSL line.   I've seen this one: , but I'm not sure if we both ask same question. For instance, I don't need, simultaneously, data and voice. I could disconnect internet connection, if needed. And this other: , seems to much complicated. I don't need multiple lines.   Thanks.     EDIT :  I think my question is not duplicated, because is not answered in that post.   If I'm not wrong (correct me if I am), all answers, like asterisk, need a SIP provider, and that's not what I want. I don't want to pay for another provider. I already have a company who provides my land line (and internet).   In other words: I don't want to make calls through internet, I want to make calls from computer using my land line provider. Is that possible?


What is the point of putting two lstm cells one after another?

I've seen something like this a lot in literature : "we used x lstms cells in our implementation". I don't understand the point of using several stacked lstms : indeed, why isn't a single cell enough as it already takes the cell state and the hidden state from the previous time step ?  For example page 4 of this paper :   I see the advantage of parallelizing two cells but not the one of stacking.


SQL Server 2014 - Strange SP behavior during compilation

Today I noticed a strange behavior during the creation of a stored procedure in SQL Server 2014.  Below is my test procedure. Please explain why SQL Server disallows compilation with the first SELECT and allows compilation with second one.  CREATE PROCEDURE [dbo].[test] AS BEGIN      SET NOCOUNT ON;      IF 1=0  -- this will never occur     BEGIN         select x from Table -- TABLE EXIST BUT COLUMN NOT - STORED PROCEDURE IS NOT CREATED         --Msg 207, Level 16, State 1, Procedure test, Line 25         --Invalid column name 'x'.          -- But if i change          select x from TableWhichNotExistInDatabase  -- This table not exist in database, but stored procedure has been created without any problems and I can exec it without errors (    because of 1=0 in if )      END     ELSE      SELECT '' END   In my real procedure, I'm creating temporary tables with various schema (from XML passed as parameter). Next I'm trying to validate some data in the stored procedure. Validation blocks are controlled by IF statements.   The creation of temporary tables and the stored procedure call is executed by a dynamiclly created procedure.   I think the problem lies somewhere during the creation of the execution plan or something like that. If the table does not exist in the database, SQL Server allows the creation of the stored procedure when a table does not exist.  However, when the table exists, the creation of the stored procedure fails because of invalid schema - no column.  I was looking for a solution which disables schema checking but did not have any success.  Are there any ideas regarding how can I bypass this limitation?


I want to use a formula which allows me to categorize my data into 3 groups. I want:   Units shipped <100 to be called Group "A" Units shipped Between 100-999 to be group "B" Units Shipped >1000 to be group "C"     I have tried:  IF(Sales<100,"A", IF(AND(Sales>=100, Sales<=999, "B", IF(Sales>1000, "C",0)))   But it keeps coming up with the:     we found a problem with this formula   error message and I can't work out what is wrong with the formula.


If A and B are square matrices and the product is invertible is A necessarily invertible?

Let $A$ and $B$ be square matrices, where the product $AB$ is invertible. Is $A$ necessarily invertible?  (HINT: You cannot assume that $(AB)^{-1}= B^{-1} A^{-1}$, since we do don't know $A$ and $B$ are invertible. You can set $(AB)^{-1}=C$, and think about what the product $(AB)C$ would equal, to attempt to find an inverse to $A$)


How should I interpret this residual plot?

I am unable to interpret this graph. My dependent variable is total number of movie tickets that will be sold for a show. The independent variables are the number of days left before the show, seasonality dummy variables (day of week, month of year, holiday), price, tickets sold till date, movie rating, movie type (thriller, comedy, etc., as dummies). Also, please note that movie hall's capacity is fixed. That is, it can host maximum of x number of people only. I am creating a linear regression solution and it's not fitting my test data. So I thought of starting with regression diagnostics. The data are from a single movie hall for which I want to predict demand.  The is a multivariate dataset. For every date, there are 90 duplicate rows, representing days before the show. So, for 1 Jan 2016 there are 90 records. There is a 'lead_time' variable which gives me number of days before the show. So for 1 Jan 2016, if lead_time has value 5, it means it will have tickets sold until 5 days before the show date. In the dependent variable, total tickets sold, I will have the same value 90 times.  Also, as a side remark, is there any book that explains how to interpret residual plot and improve model afterwards?


How to switch background image during video compositing?

Greetings, as you can see in the picture, I want this picture to be background image for my amateur video. Any advices?


I have such string: "172.17.0.030". I should return False cuz it's not a valid ip address. How can I check that last octet contains not valid value (not in base of 10)?


I downloaded Dropbox from the official site and then installed it via Ubuntu's software installer. A message advised me to restart my session, so I logged out and in. No Dropbox.  So I chose Dropbox by searching it and the clicking via Activities. The message about installing Dropbox and then about restarting Nautilus appeared. I made my choices, but no Dropbox.  From command line, I chose dopbox running - no Dropbox. dropbox start gives the following message:  Starting Dropbox...Traceback (most recent call last):   File "/usr/bin/dropbox", line 1535, in <module>     ret = main(sys.argv)   File "/usr/bin/dropbox", line 1524, in main     result = commands[argv[i]](argv[i+1:])   File "/usr/bin/dropbox", line 1395, in start     if not start_dropbox():   File "/usr/bin/dropbox", line 732, in start_dropbox     stderr=sys.stderr, stdout=f, close_fds=True)   File "/usr/lib/python2.7/subprocess.py", line 390, in __init__     errread, errwrite)   File "/usr/lib/python2.7/subprocess.py", line 1025, in _execute_child     raise child_exception OSError: [Errno 8] Exec format error   I've tried this over and over with exactly the same result. Anybody know how to install Dropbox?


Equivalent Rotation using Baker-Campbell-Hausdorff relation

Is there a way in which one can use the BCH relation to find the equivalent angle and the axis for two rotations? I am aware that one can do it in a precise way using Euler Angles but I was wondering whether we can use just the algebra of the rotation group to perform the same computation?


How much safer is RSA-OAEP compared to RSA with PKCS#1 v1.5 padding?

Is there a way to calculate how much safer RSA-OAEP is compared to RSA with PKCS#1 v1.5 compliant padding? Or is there a good rule of thumb?


Difference between a LED Backlit and LED HD Display on laptop monitor

Is there a difference between a LED Backlit and LED HD  Display on laptop monitor? or are they the same that is good for the eyes


Landscape environment in variable position

I have a portrait document, and I want to put a big table in a landscape page. I am currently using the landscape environment to achieve that.   As this page is in the middle of the document, I want the previous page to be always full (i.e., there must not be a remaining space between the previous page and the landscape page). Is there any way to accomplish this, taking into account the document content changes frequently? I use pdflatex to compile the document.


How to handle people impersonating other people by choosing the same display name

What is done to prevent people from changing their display name to another persons', for example Jon Skeet, and then also changing their gravatar to match too?  In comments it seems there is no visible differentiator, and the differentiator in questions and answers is just reputation and badges.  This doesn't seem to be a problem for stackoverflow, but I'm just wondering what are possible safeguards against this?  EDIT: Also it doesn't even have to be deliberate, if two people just happen to choose the same display name, and they both participate in the same question/comment thread, that would be confusing right?


How to use stringstream to separate comma separated strings

I've got the following code: std::string str = "abc def,ghi"; std::stringstream ss(str);  string token;  while (ss >> token) {     printf("%s\n", token.c_str()); }  The output is:  abc def,ghi  So the stringstream::>> operator can separate strings by space but not by comma. Is there anyway to modify the above code so that I can get the following result?  input: "abc,def,ghi" output: abc def ghi


How to get coordinates when only pairwise distances are known?

I have $n$ points with pairwise distances known, $d_{i,j}: 0<i,j<n$. Their coordinates, $\vec{x}_i \in \mathbb{R}^k: 0 <i<n$, are unknown. I can set up $n^2 - n$ equations to solve for coordinates: $$ (\vec{x}_i - \vec{x}_j) \cdot (\vec{x}_i - \vec{x}_j)^T=d_{i,j}^2, i \neq j $$ Assuming coordinates are $k$-dimensional, this system of equations will have a single solution if $(n^2-n)/2 \geq k \cdot n$ i.e. enough equations to cover the number of variables ($n$ points times $k$ dimensions). Otherwise there will be infinitely many solutions. In either case, are their algorithms for getting coordinates (or one possible solution) only from pairwise distances? I want to apply this in a python codebase - do existing libraries implement this?


What is the advantages in using foreign keys and disadvantages in not using?

I always create my tables thinking about how they will relate and then put then to work with no dependencies. FK declarations sometimes make tables harder to alter when there is data already, so I don't use them. After all when I need to relate tables I use some joins. The only thing I see of good in FK is the alert when you try to delete some data binded to others and the cascade feature.   But I know I am a little noob, so, what else is wrong in not declaring FK and what is good about not using it, if there is any?


What is the maximum number of consecutive composite numbers possible?

Can anyone tell me what is the maximum number of consecutive composite numbers possible? I mean can I get say 1000 consecutive natural numbers. Is there any general theorem that when I have a n-digit number there will always be p consecutive composite numbers?


Mathematically show that Quantum Mechanics and General Relativity are inconsistent

I've read paragraphs all over the internet about why they don't fit in. But, if possible, can someone please give me the mathematics of the inconsistency?  Mathematically show what happens when the formulas of quantum mechanics are applied in high gravity situations. And, give me the mathematics of what happens when General Relativity is applied to Atomic scales.  Mathematically show that both the models are inconsistent with each other.


Is it intentional that the profile reputation display in the revision history doesn't match the way it is displayed elsewhere?

I noticed that in the revision history, reputation over 10K isn't displayed in the shortened format used in other places. For example, in  my reputation on ELL is displayed as "11251" but it is displayed as "11.3K" when looking at the question. Is that intentional, or an oversight? I don't know if it has always been that way and I just noticed it, or if this is something new. I prefer the shortened format, especially for users that have 100K or more reputation.


I had a logical volume root that was 20GB and another logical volume (named Boobies, yes I know it's childish) with 200GB. I downsized the other to 100GB and extended the root to 120GB.  But the root directory is still just 20GB.  The root logical volume gets mounted as / in fstab. How do i get my system to recognize the resized root? Running arch btw


Evaluating $\int_{-a}^a \frac{f(x)+1}{b^x+1}\,\mathrm dx$ for a $y$-axis symmetrical function $f$

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


I have Ubuntu 16.04 LTS installed on my PC. I have a problem playing  videos on google chrome. Version of google chrome: 51.0.2704.63 (64-bit). All other videos of youtube are playing normally in google chrome. I even tried playing the  videos on Firefox but the same problem persists. Can anyone help me with the same ?


What is the best word describing the nature of expiring in a short amount of time, connoting "losing public attention"?

Is there an adjective that describes the nature of expiring, connoting a sense of losing public attention, in a very short amount of time? For example,  In a fast-paced era, news articles are ____. During the 1990s, compared with traditional technologies, computer  technologies are ___; for example, a new generation of CPU technologies usually comes out every one to two years.  (I thought about "perishable," but it does not seem connoting "losing public attention.")


Can a cleric "multi class" between domains?

I have a player asking me if there is a mechanic that would allow them to take on a second domain, much in the same way a player can multi class. My gut here is no and I am contemplating instead finding out which 2 domains they wish to combine and then forming my own homebrew deity and domain that takes aspects of each, but not everything. But is there a RAW way that a player could take on multiple domains as a cleric?


I hope the picture is clear enough, I've found a worm like insect like the one below a little while ago in my shower, and today I found another one. I've never seen something like this. I would say it is slightly bigger than a centimeter.  Location: Netherlands  Why do they come in my shower ?


In finite dimension, $W_1^0+W_2^0=(W_1\cap W_2)^0$

Let $V$ be a vector space. For any set $S\subset V$, we define $S^0=\{f\in V^\ast\,:\, f(v)=0,\forall v\in S\}$. If $\dim V<\infty$ and $W_1,W_2\subset V$ are vector subspaces, then show that $W_1^0+W_2^0=(W_1\cap W_2)^0$.     I was able to show that $W_1^0+W_2^0\subset (W_1\cap W_2)^0$: Let $f\in W_1^0+W_2^0$. Then there are $f_i\in W_i^0$, $i=1,2$ so that $f=f_1+f_2$. If $v\in W_1\cap W_2$, then $f(v)=f_1(v)+f_2(v)=0$, since $v\in W_1$, $f_1\in W_1^0$ and $v\in W_2$, $f_2\in W_2^0$. Therefore $f\in (W_1\cap W_2)^0$.  I don't have any idea of how to do the converse inclusion!


Incrementing value in a loop yields different (wrong) value?

I have spent almost all day trying to figure out why this is happening, I had code that incremented a float if it was not a whole number until it was a whole number, i'd trigger it by incrementing the value by 0.01 and the loop keeps incrementing it by 0.01 until it is an integer however it never stops, debugging it I noticed that the number to becoming increasingly inaccurate as the loop progressed leading to it being 0.0000066 out by the end. I thought maybe the variable might had been being accessed elsewhere somehow so I created it simply in an empty "main" program:  float value = 0; for (int i=0; i<100; i++) {     value += 0.01f; } System.out.println(value); // Displays 0.99999934 System.out.println(value == 1); // Just in case it's displaying wrong in println (displays false)   Why is this not 1 by the end? I don't think it could be anything to do with data types as i'm adding a float to a float.


How to construct a bijection between $[1,6)$ and $(-3,3)$?  I've tried to come up with a proper bijection, but haven't had any luck. Any ideas how to solve it?


I have studied that every normed space $(V, \lVert\cdot \lVert)$ is a metric space with respect to distance function  $d(u,v) = \lVert u - v \rVert$, $u,v \in V$.   My question is whether every metric on a linear space can be induced by norm? I know answer is  no but I need proper justification.   Edit: Is there any method to check whether a given metric space is induced by norm ?  Thanks for help


Why no gui option to open a program as root?

Just wondering why there is no option in Ubuntu's desktop environment to open a program, for example Nautilus, as root. I know that I can accomplish this in the terminal, but wouldn't it benefit the Ubuntu's usability to allow this to be done by simply right clicking on a program?


How to fix "*:i386 cannot be configured because *:amd64 is in a different version"?

I've managed to break apt-get, I think it had something to do with competing versions of libqt between supercollider and Skype. When I run apt-get -f install I get:  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required:   libxml++2.6-2 libffado2 libconfig++8 libssl1.0.0:i386 Use 'apt-get autoremove' to remove them. The following extra packages will be installed:   libqt4-declarative:i386 libqt4-sql-mysql libqt4-sql-mysql:i386 libqt4-test qdbus Suggested packages:   libqt4-declarative-folderlistmodel:i386 libqt4-declarative-gestures:i386 libqt4-declarative-particles:i386 libqt4-declarative-shaders:i386 qt4-qmlviewer:i386   libqt4-dev libqt4-dev:i386 The following packages will be upgraded:   libqt4-declarative:i386 libqt4-sql-mysql libqt4-sql-mysql:i386 libqt4-test qdbus 5 upgraded, 0 newly installed, 0 to remove and 449 not upgraded. 14 not fully installed or removed. Need to get 0 B/1,236 kB of archives. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? y (Reading database ... 183437 files and directories currently installed.) Preparing to replace libqt4-sql-mysql 4:4.8.1-0ubuntu4.1 (using .../libqt4-sql-mysql_4%3a4.8.1-0ubuntu4.2_amd64.deb) ... Unpacking replacement libqt4-sql-mysql ... dpkg: error processing libqt4-sql-mysql:i386 (--configure):  libqt4-sql-mysql:i386 4:4.8.1-0ubuntu4.1 cannot be configured because libqt4-sql-mysql:amd64 is in a different version (4:4.8.1-0ubuntu4.2) dpkg: error processing libqt4-sql-mysql (--configure):  libqt4-sql-mysql:amd64 4:4.8.1-0ubuntu4.2 cannot be configured because libqt4-sql-mysql:i386 is in a different version (4:4.8.1-0ubuntu4.1) Errors were encountered while processing:  libqt4-sql-mysql:i386  libqt4-sql-mysql E: Sub-process /usr/bin/dpkg returned an error code (1)   I read that I could fix this by installing aptitude and removing and reinstalling broken packages, but I can't install it using dpkg.


Is it possible or even acceptable to use the present perfect with today (in those cases when today refers to the present age)? Even native speakers seem to disagree!! For instance; today, companies have thrived on foreign investment.   Thank you!


ArcMap basemap layers take a long time to display

Over the years I've often used two of the available ArcMap basemap layers (Imagery and USA Topo Maps) as part of my work.  I've noticed that ArcMap consistently takes 10-15 seconds for the screen to refresh each time I pan or zoom to a new mapextent.  This delay only occurs when I have a basemap layer turned on for display.  I find my productivity lagging as I stare at the screen, waiting for it to refresh.    Yet at the same time other programs (QGIS, Google Maps) refresh their basemap imagery almost instantaneously.  I thus conclude that the problem is with Arc, and not my internet connection speed (direct ethernet connection with typical download speeds > 200 Mbps) or computer power (currently a sixth-gen i7 processor with a dedicated GPU and SSD).  I'm using Arc 10.5, but I've noticed this slow basemap refresh problem ever since ESRI has provided the service (9.0?).  I've always had Hardware Acceleration enabled via the Arcmap Options.    If I return the map extent to a previous view, the imagery displays quickly, implying that Arc is correctly caching the imagery.  But the slow basemap refesh problem always occurs if I pan/zoom to a new area.    I'm not using any advanced cartographic features such as representations, and all of my work is on a local machine - no remote connections.  Is this slow basemap refresh typical?  If not, are there any tips to speed it up?


When is 16.04 going to be officially available on AWS?

It doesn't seem to be avail on  nor I can find any when searching on AWS itself


For square matrix, right or left inverse is equivalent to inverse.

Definitions:         Let $A$ be an $n\times n$ matrix. The $n\times n$ matrix $B(=A^{-1})$ is an inverse for $A$ if $AB=BA=I$.   Let $A$ be a $k\times n$ matrix.The $n\times k$ matrix $B$ is a right inverse for $A$ if $AB=I$.The $n\times k$ matrix $C$ is a right inverse for $A$ if $CA=I$.   Here $I$ is  identity matrix of appropriate order.      Now,      Theorem 2: For any square matrix $A$, the following statements are equivalent:         $A$ has inverse.   $A$ has a right inverse.   $A$ has a left inverse.      I know that      Theorem 1: If $A$ has a right inverse $B$ and a left inverse $C$, then $A$ is invertible and $B=C=A^{-1}$.   Proof: $C=CI=C(AB)=(CA)B=IB=B.$   But I can't prove Theorem 2 .


HDD clicking and not showing up on BIOS/Windows 10

Recently, this HDD has been having some issues: sometimes, I tried to open it on Windows and it took a while and only then it showed the folders inside; sometimes, the HDD didn't even appear, and then often I just restarted the computer and then it would appear. Today, it didn't appear, I restarted the computer, but nothing. I tried to replace the external circuit board with another one from a new similar HDD. But it just keeps making a clicking sound (~1 click per second), probably the head touching the center of the disk. You can watch it in this video:   Can I recover the data from this disk? Can I do it? I have similar disks. Or do I have to take it to some professional? Thanks a lot.


Turning off "Update page numbers only" in Word

When I update the fields document-wide (Ctrl + A, then F9) in a Word document that has a table of contents, a dialog appears asking if I want to update page numbers only, or update the entire table. I never want to update page numbers only if the document headings have changed, nor will I ever.  (Apparently this is given as an option in case someone has manually changed an automatically generated ToC, which is almost always a really bad idea.)   Unfortunately, "Update page numbers only" is the default selection in the dialog, which means that I have to select the other option every time. I update the fields all the time when I'm working in a document that has figures and cross-references, so this is an annoying extra step I'd really like to get rid of.   Is there any way to tell Word to stop asking me this stupid unnecessary question?


How to add a custom action to the list items display form ribbon?  Onclick of this it should open a application page in modal popup.


What does the [x,y] symbol mean in a multidimensional array access?

I'm studying C and I came across the code below. The printed results are always the same for all the printf calls.   What does [x,y] mean?  A memory address or something else?  printf("%d ", array[0,0]); printf("%d ", array[1,0]); printf("%d ", array[2,0]);


When I extend a parent class which has a **kwargs, I can not write kwargs in super(ParentClass, self).__init__(args, kwargs). Why is it like this?  Code as follows: Originally I think below is right, but it is not.  class Parent(object):   def __init__(self, *args, **kwargs):     pass  class Child(Parent):   def __init__(self, *args, **kwargs):     super(Child, self).__init__(args, kwargs)   In fact, below it is right after I test.  class Parent(object):   def __init__(self, *args, **kwargs):     pass  class Child(Parent):   def __init__(self, *args, **kwargs):     super(Child, self).__init__(*args, **kwargs)   When we reference a arg like *args, **kwargs, usually we directly use args, kwargs. Why here when I write a __init__, I can not do that?


How should one interpret the comparison of means from different sample sizes?

Take the case of book ratings on a website. Book A is rated by 10,000 people with an average rating of 4.25 and the variance $\sigma = 0.5$. Similarly Book B is rated by 100 people and has a rating of 4.5 with $\sigma = 0.25$.   Now because of the large sample size of Book A the 'mean stabilized' to 4.25. Now for 100 people, it may be that if more people read Book B the mean rating may fall to 4 or 4.25.   how should one interpret the comparison of means from different samples and what are the best conclusions one can/should draw?    For example - can we really say Book B is better than Book A.


Why isn't force $\vec{F}=m \vec{v}$ instead of $\vec{F}=m \vec{a}$?

Why isn't force $F=m\vec v$ instead of $F=m\vec a$? If I'm standing in a wind that's blowing at a steady 100 mph, would that not impart a force on me?


If $T^k = Id$ for $k\ge 1$ then $T$ is diagonalizable

Let $V$ a finite dimension space over $\mathbb{C}$ and $T:V\to V$, a linear transformation such that $T^k = Id$ for $k\ge 1$. Prove that $T$ is diagonalizable.   I'd be glad for an hint. How do I approach this question?  Thanks.


Terminal shortcut to go to beginning of command?

For example, forgetting to put sudo and having to go back to the beginning of the command.


How do I reset all progress in the game "just shapes and beats"?

The game  has a very unique intro that I would like to show my friend again for the first time. I'm not sure how to reset all my progress on this game to achieve this though. Any thoughts?


How to use Named credentials in SOAP callouts?

Can someone here please help me in accessing named credentials in SOAP callouts like we do in REST ?


I am creating a simple module which will be sending HTML emails to users for deals in our website.  I have searched a lot, but I can't find a solution proper solution for Drupal. Now I can send mails but plain text.  What is a step-by-step procedure to send HTML emails in Drupal 7?  function example_form_submit( $form,&$form_state) {     $friend_email=$form_state['values']['friend_email'];     $mailto =$friend_email;  //gift to a friend     $mailfrom ='no-reply@example.com';     $subject = "another message for  HTML email from example.com";     $body="
Hello EMAIL, i here i want to be bolded
";     if (drupal_mail('example', 'send_gift', $mailto, language_default(),$params,$mailfrom,TRUE)) {         drupal_set_message(t('Your gift was sent successfully!!!'));     }     else {         drupal_set_message(t('Error occured while sending your mail!!!'));     }   /****hook_mail*/ function example_mail($key,&$message,$params) {     $language = $message['language'];     switch ($key) {         case 'send_gift':             $message['subject']=t($params['subject'], $var, $language->language);             $message['body'][]=$params['body'];             $message['headers']['Content-Type'] = 'text/html; charset=UTF-8; format=flowed';         break;     } }


How to get current DateTime from client?

I want to show current client DateTime with a blazor component.  Which time does next code present?  <div>@DateTime.Now</div>   I think it will be server time. How can I get client OS time?


How can I render a box to emulate an SMS conversation on a mobile device?  Something looking like this (only the inner boxes containing the actual conversation):  Note that I would like this to be used within a standard document, such as article or book, so the answer  is not strictly applicable, since it achieves a good result via a dedicated and standalone document class.    This is what I have done so far, but I would like to add the little 'tags' on the lower left and right corners, etc...  \documentclass{article}  \usepackage[framemethod=TikZ]{mdframed} \mdfdefinestyle{MDSMSLEFT}{%     linecolor=blue,     outerlinewidth=1pt,     roundcorner=5pt,     %innertopmargin=\baselineskip,     %innerbottommargin=\baselineskip,     innerrightmargin=5pt,     innerleftmargin=5pt,     backgroundcolor=blue!50!white}  \newcommand{\smsleft}[1]{     \begin{minipage}{0.75\linewidth}         \begin{mdframed}[style=MDSMSLEFT] #1 \end{mdframed}     \vspace*{\baselineskip}     \end{minipage}\par }  \begin{document}  \smsleft{This is a message}  \end{document}


Prove that the sum of two continuous functions is continuous using epsilon delta.

$$\lim _{x\rightarrow a} f(x)+g(x) = f(a)+g(a)$$  Let $ε>0$ be given  Since $f$ and $g$ are continuous, $|f(x)-f(a)|< ε$ when $0<|x-a|< \delta_f $ and $|g(x)-g(a)|< ε$ $\ $ when $0<|x-a|< 𝛿_g$  Let  $𝛿_h$ be defined as $\min(𝛿_g ,𝛿_f)$ and $h(x)$ be defined as $f(x)+g(x)$  $\ |f(x)-f(a)|+|g(x)-g(a)|< 2ε$                $\ |f(x)-f(a) + g(x)-g(a)|< 2ε$  $\ |h(x)-h(a)|< 2ε$  We can replace $𝛿_f$  and  $𝛿_g$ by  $𝛿_h$ to get  $|f(x)-f(a)| < ε$ when $0<|x-a|<𝛿_h$ and $\ |g(x)-g(a)|< ε$ when $0<|x-a|<𝛿_h$  How do I prove that $\ |h(x)-h(a)|< ε$ instead of $\ |h(x)-h(a)|< 2ε$?


I am inquiring as to why an intercept/constant in a regression would increase if a variable is controlled for?


Keep the message ID in the text field so I can reply to a message with an upload

When I click the arrow icon to start a reply to a chat message, the text field is prepended with a colon followed by the message ID. This also works even if you've entered something in the text field, so  Replying to somebody   becomes  :1234567 Replying to somebody   But since an image upload will submit immediately, I have to start the reply before uploading.  But that doesn't work either. The message ID that's prepended ends up being erased and replaced with the image URL before the upload submits. I have to edit to include the message ID to turn it into a reply, and since editing a message with a onebox causes the onebox to reload, it can get distracting.  Can we please preserve the message ID so  :6059107   becomes  :6059107 http://i.stack.imgur.com/uzFM3.png   and not  http://i.stack.imgur.com/uzFM3.png   instead so I don't have to edit it or upload it separately?  EDIT [11/20]: just found out that the upload button is totally disabled when the field isn't empty now. I guess it's to stop any message being completely replaced with the upload URL, so perhaps seeing it from that perspective, it's a good thing. It doesn't exactly help matters here, though.


Can't edit/add a specific content type sometimes - SQL has gone away

Hi Can anyone help with this situation.   I am on Drupal 7.12 and I am getting a white page (or if I have enabled errors to show, a SQL has gone away error when I try to add or edit a specific content type:  PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT rid, permission FROM {role_permission} WHERE rid IN (:fetch_0); Array ( [:fetch_0] => 1 ) in user_role_permissions() (line 752 of /var/www/vhosts/pen.org/staging.pen.org/modules/user/user.module).  This only happens sometimes and when it does lasts a couple of days. And it goes away suddenly. During the time it happens, other content types are editable. The site also functions fine.   Has anyone experienced this before? Any insight is much appreciated.  Thanks.


I'd like to be able to tail the output of a server log file that has messages like:  INFO SEVERE   etc, and if it's SEVERE, show the line in red; if it's INFO, in green.  What kind of alias can I setup for a tail command that would help me do this?


Popup when opening files in Telegram Desktop snap

I have a super weird question. Whenever I try to open a file or try to show a file by clicking on the message in Telegram Desktop, this popup shows up:      I always have to click 'Yes', which is super annoying 'cause I open so many files.  By the way, I'm using Ubuntu 16.04 and Telegram Desktop version 1.4.3.  Does anyone know how to resolve that and give permanent permission?


how to switch between 2 connections on windows?

Is there a way (I guess there is) to switch between 2 internet connections on my windows 7/8/10 ?  I have my wifi connected AND my USB android modem and I would like to switch programatically (command line) from one to other.   Mybe some netsh command ?    I want to switch between proxymis.com network and androidS4 on my wifi.


strictly positive elements in $C^*$-algebra

Let $A$ be a $C^*\text{-algebra}$ and $A_+$ denote the positive elements. An element $a\in A_+$ is called strictly positive if $\overline{aAa}=A$. Want to find the following:a)What are the strictly positive elements of $C_0(\Omega)$ where $\Omega$ is locally compact Hausdorff space, and $C_0(\Omega)$ is the space of continuous complex valued functions that vanishes at $\infty$.b)If $A$ is unital, then $a\in A_+$ is strictly positive iff $a$ is invertible.c)if $(e_n)$ is an approximate identity of $A$, then $a:=\sum_{n=}^{\infty}\frac{1}{2^n}e_n$is strictly positive.What I tried and know:a) I know that positive elements in this space are functions with positive images, and thus, strictly positive elements are functions with positive images and now real root. is this correct? and how can I show that the positive elements are these kind of functions.b) I figures out that if $a$ in invertible then $a$ is strictly positive, but no idea how to do the other direction.c)I did this but using another characterization of strictly positive elements but want to do it with this one, and I don't know how.Thank you for your help.


Does a Python module ever change functionality (due to source code changes) after it is first imported

I have a Python script which   calls a function foo which imports and uses module my_module  does some lengthy calculations calls a function bar which also imports and uses module my_module   If my_module.py is changed at some point during step 2, will bar always use the same my_module that was used in  foo ?  What if I run another Python script during step 2. that also imports my_module?  I created the toy scenarios above, and it seems like my_module indeed stays the same for all its calls in the original Pythons script, but I'd like to have a guarantee for that or know situations in which it could fail.  (Background: This is for scientific software development. I write an algorithm, commit to git, run it to see if it works and what it produces, and while waiting for it to finish continue working on its source. If I don't like the results, I'd like to know what exact source was responsible for the results.)


I've removed totem and installed VLC instead. Now video files thumbnails are gone. Is there any way to get thumbnails back without reinstalling totem?  I know I can have both totem and VLC, but I really don't want to have more soft than I need :)


I know we would not say a 3 months period, but why exactly? Is it because period is noncount? But why is it correct to say a period of 3 months   How do you know when to pluralize nouns and when not to? Is there a website that breaks down examples like period for me?  Thank you!


Auto incrementing column P100-001, P100-002 etc

Within our SharePoint Enterprise 2013 On-Premise environment we have documents that need to be tagged with codes for example:   Procedure Document: P100-001 Forms: F100-001   So when a procedure document is upload I would like it to get assigned the next available code, e.g. P100-002.  What is the best approach for this?  EDIT: So it looks like the best solution is to use a workflow, I have created the workflow but unsure of what I need to type    Basically I want a string of text P100- and the add the item ID


I have always problem with finding a suitable sentence to avoid a gender dependent pronoun. I know I can use "they" or "their", but if there were other options to totally omit them, I would prefer them.  For example I wrote:     The user can utilize this information to create appropriate rules to identify his items of interest.    Can I here say "the items of interest"?  Are they other options? In general?


when i press the mirror modifer nothing happens to my shape im a noob at blender so could someone please help? i've tried all other solutions that related to my post but none of them worked.


I need to find the infinite sum of the following series expansion   $$1/3 + 2/3^2 + 3/3^3 + 4/3^4 + \dots + k/3^k + \dots$$  I know that  $$x/(1 - x) = x + x^2 + x^3 + \dots + x^k + \dots$$   We need to find the $x$ value in order to find the infinite sum. What could the $x$ value be? I am not sure.


Well, I was studying laws of indices and the following steps came to my mind  $(-1)^{\frac {1}{2}}$  = $(-1)^{\frac {2}{4}}$  = $((-1)^{2})^{\frac {1}{4}}$  = $1^{\frac {1}{4}}$  = $1$  This is very strange, but I cannot find the mistake. In fact, $\frac {1}{2}$ and $\frac {2}{4}$ represent the same rational number and so the first step is alright. My second step is also correct as that is the definition. The remaining steps are also true. I'm confused!


Sauerkraut/sourkraut - ratio of grams of salt to grams of raw cabbage?

Yes, obviously it can vary. I'm just looking for an approximate range, as a good place to start for my first time making a batch.  A good answer would be something along the lines of:     10 to 20 grams of salt per 100 grams of raw cabbage   Or something like that.  [EDIT: that was just the format of answer I wanted. That actual ratio would probably be about ten times too much salt.]


Does the Wizarding world holds elections

Is the Ministry of Magic elected? Is the (British) magical world a democracy? What political parties exist? How are elections organized? How frequent does one can/have to vote?  In Harry Potter and the Half Blood Prince, we learn that Albus Dumbledore was offered the post of Minister for Magic three times. This seems to imply one at least doesn't have to volunteer to get elected?


Husband's UK visa rejected after 10 years of successful applications, made one mistake applying for EEA permit just before this visit visa application

Here is the refusal letter. We don't know what to do now and how to apply again, as we applied with the same format we have used for a decade.


Can't select anything or see selection in the viewport

I can't select anything in the 3D viewport, and I don't see the gizmos axis or selected objects.


Prove that $\mathrm{Res}(\frac{f(z)}{g(z)}, z_0) = \frac{f(z_0)}{g'(z_0)}$

Show that if $f$ and $g$ are analytic on a neighborhood of $z_0$ with   $f(z_0)\not= 0$ and $z_0$ is a simple zero of $g$, then we have   $\mathrm{Res}(\frac{f(z)}{g(z)}, z_0) = \frac{f(z_0)}{g'(z_0)}$.   I know that $\mathrm{Res}(f,z_0)+a_{-1}= \int_{C_p} \frac{f(z)dz}{z-z_0}$, where $C_p$ is simply the circle at $z_0$ with radius of convergence $p$ ($0<p<r$) in positive direction.  How could I prove this exercise? Any ideas?