I'd like to set up a DNS service on the same server that I use to host a domain's websites. I understand that this is not recommended, but there are a number of external factors prompting me to do this.  With a web server running on Port 80 & 443, I could easily run a DNS Service on port 53.  My question is the following: to point a registrar to a nameserver, you can't use an IP, so something like ns1.example.com would be required. Where and how would you be able to point ns1.example.com to the webserver, if you're not using the registrar's nameservers?

This question was originally asked here:   To summarise: "When I go to my registrar and purchase example.com , I will tell my registrar that my nameservers are ns1.example.org and ns2.example.org".  But please can somebody clarify the following:  After registration, the .com registry will now have a record that tells a resolver needs to visit ns1.example.org or ns2.example.org in order to find out the IP address of example.com. The IP address resides in an A record in a zone file on ns1.example.org and has a identical copy on ns2.example.org.  However, inside this file, there must also be 2 NS records which list ns1.example.org and ns2.example.org as the nameservers. But since we are already on one of these servers, this appears do be duplicated information.   The answer originally given to the question said the nameservers listed in the zone file are "authoritative". If the nameservers didn't match, then the authoritative nameservers would take precedence. That's all very well and good, but the resolver arrived at the nameserver using the nameservers listed in the .com registry, and if the nameserver's didn't match, then the resolver would be looking for the zone file on the wrong nameserver and wouldn't be able to find it.  Or is it a case of the .com registry extracts nameserver information from the zone file ns record? (But then I suppose if you change the ns record the zone file without telling the registry, then it would have no way of knowing where to look.)   Thanks


I seem to be having an issue with my applications not obeying the umask. in shell everything seems to be correct, i set my umask to be 002 in a sourced app_env.sh script. this is working correctly as a shell i open will obey this. When i open the file browser and create a new folder, it sets it's permission to be 755.. I also see other applications creating files in this manner, i am unsure of where to set umask so that my applications should follow the rule. I looked around and couldnt find any solutions so far, just unanswered questions on many forums.

Using Gnome 3.18. I share files between other family members, but the default umask on my distro (archlinux) is 0022. So every file/directory created is not writable for our common group.  I tried to put umask 0002 in /etc/profile but the gnome session is still using 0022. It's working for a login bash shell, though.  I also tried to add this line in /etc/pam.d/system-auth:  session   required  pam_umask.so umask=0002  It has the same effect as the one in /etc/profile. I tried  If I change the umask manually in a gnome-terminal shell, then I launch an application from it, say gedit, then the files created by it have the wanted permissions. If I launch gedit from the gnome menus, it doesn't. So my matter is really to set the umask for the gnome session, and I can't find where to do it.  EDIT (to answer Gilles' comment): I'm using gdm 3.18 as the DM. I also tried to add the pam_umask line into /etc/pam.d/gdm-launch-environment. All other gdm-* files contains includes of session from the system-auth file, so they should not need more. It doesn't change anything.  /etc/login.defs contains UMASK 077 but also USERGROUPS_ENAB yes which should set the umask to either 0077 or 0007 for users whose primary group is the username.  The only file that contains 022 for umask in /etc is /etc/profile but that was my first try.  As for /etc/Xsession.d, I don't have this directory. Besides, as wayland is now the default display server, I'm not sure the umask should be set as part of X initialisation, even if I'm still using it myself.


How do I change the font and font size in dash to panel?

First the picture:    As you can see in the image, the colors used for the icons and the words Applications and Places (In spanish in this case) have a different background dark gray color than the rest of the panel. Also the icons look rather bigger in that panel. Now my questions are:   Can the background colors be customized so they look the same all the way through the panel. Can the icons be somehow minimized a little so they don't look strange (bigger actually) How to edit the way to add icons to the panel. I have to actually hold the ALT key and right click on it to show the context menu which shows me the option to add something. That extra key press is not friendly at all.   In this particular case I am trying to help an older man start in Ubuntu. Unity is too much for him but Gnome is friendlier for him (Learning curve is not the best for older people.. specially 68+ year old people).


Filipino citizen traveling from Saipan via Korea with 13 hours lay over going to manila with NO either U.S. visa or Korean visa can take Korea airport city tour?

I am a Filipino citizen traveling from Saipan to Manila via Seoul, with 13 hours layover.  Do I need a Korean visa to take the airport free city tour?


I noticed that some python scripts start with  #!/usr/bin/env python   instead of  #!/usr/bin/python   Are python scripts the only ones that use #!/usr/bin/env? Are there any scripts that start out with for example #!/usr/bin/env bash or #!/usr/bin/env perl? If not then why are python scripts different?

In scripts, first line should specify the path to interpreter. But on different servers Linux, Unix, or BSD this path could be different.  What is more preferable?  #!/usr/bin/env bash    or  #!/bin/bash


What is the difference between crontab -e and nano /etc/crontab? Do they point to the same thing?

Trying to set up a daily cron job to shut down a server.   One source suggests editing /etc/crontab  Another suggests crontab -e (with sudo)  I tried the latter, and my process did not run (if I recall, it was 30 23 * * * shutdown -h)   I also note that in the nano editor, it was working on a .tmp file? (top of nano says: /tmp/crontab.9zeTNt/crontab )  What is going on? How can I fix this?


Why can't we multiply corresponding elements like addition is done?  Is there a specific reason why it won't be significant?   By definition, we have to multiply a row by columns.  Why such a definition other than multiplying corresponding elements?  Please ignore my ignorance. I had nowhere to ask. :(

If I multiply two numbers, say $3$ and $5$, I know it means add $3$ to itself $5$ times or add $5$ to itself $3$ times.    But If I multiply two matrices, what does it mean ?  I mean I can't think it in terms of repetitive addition.       What is the intuitive way of thinking about multiplication of matrices?


Generally speaking I like to change the battery once the battery is completely used up, but the system will kept notifying me once the percentage dropped below 20%. Is there a way to turn it off (or make the notification only comes up once it dropped below 5%)?

I use a bluetooth apple trackpad and keyboard, and once the battery hits 20% the bluetooth indicator in the menu bar starts flashing this lower battery warning. Normally, I wouldn't really care, but 20% battery is about 1-2 months of usage so the thing just flashes at me constantly for over a month.  Is there a way to disable this behavior?


I have Windows 2012 r2 Standard.  I get two Windows virtual machines for "free."  Is that correct?  If I do get those, can I use any media?  Do I need another license to activate it?  I do not have Datacenter on the physical host.

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


Let's say we have this C# method:  [WebMethod] [ScriptMethod(ResponseFormat = ResponseFormat.Json)] public string GetEventsJson() {   Event[] events = new Event[] {   new Event   {     Ref = 1,     Name = "Some Name",     Date = new DateTime(2017, 3, 20, 12, 0, 0),     Description = "Some Description",     Localization = "Localization"   }   };   return Newtonsoft.Json.JsonConvert.SerializeObject(events); }   And we call this web service method via CORS request. It returns string like that:  <?xml version="1.0" encoding="utf-8"?> <string xmlns="http://tempuri.org/">[{"Ref":1,"Name":"Some Name","Date":"2017-03-20T12:00:00","Description":"Some Description","Localization":"Localization"}]</string>   Now, i'm trying to deserialize this back in JavaScript, I was trying to simple:  var data = jQuery.parseJSON(JSON.stringify(json));   or   var data = jQuery.parseJSON(json);   But it only returns error with second method:  Uncaught SyntaxError: Unexpected token < in JSON at position 0   Or does nothing with first method (I cant get for example data.Description because it says it's undefined)  So the question is: what is proper way to deserialize JSON returned by C# webservice?

I created an ASMX file with a code behind file. It's working fine, but it is outputting XML.  However, I need it to output JSON. The ResponseFormat configuration doesn't seem to work. My code-behind is:  [System.Web.Script.Services.ScriptService] public class _default : System.Web.Services.WebService {     [WebMethod]     [ScriptMethod(UseHttpGet = true,ResponseFormat = ResponseFormat.Json)]     public string[] UserDetails()     {         return new string[] { "abc", "def" };     } }


I am storing the response to various rpc calls in a mysql table with the following fields:  Table: rpc_responses  timestamp   (date) method      (varchar) id          (varchar) response    (mediumtext)  PRIMARY KEY(timestamp,method,id)   What is the best method of selecting the most recent responses for all existing combinations of method and id?   For each date there can only be one response for a given method/id. Not all call combinations are necessarily present for a given date. There are dozens of methods, thousands of ids and at least 365 different dates    Sample data:  timestamp  method  id response 2009-01-10 getThud 16 "....." 2009-01-10 getFoo  12 "....." 2009-01-10 getBar  12 "....." 2009-01-11 getFoo  12 "....." 2009-01-11 getBar  16 "....."   Desired result:  2009-01-10 getThud 16 "....." 2009-01-10 getBar 12 "....." 2009-01-11 getFoo 12 "....." 2009-01-11 getBar 16 "....."   (I don't think  is the same question - it won't give me the most recent response)


Let be $(X,\mathcal{T})$ a topological space and let be $Z,Y\subseteq X$ such that $Z\subseteq Y$: so if $Z$ is compact in $X$ then Z is compact in $Y$.  To prove the assertion let be $\mathcal{V}$ an open cover of $Z$ in $Y$ and we consider the open cover $\mathcal{U}=\{U\in\mathcal{T}:U\cap Y\in\mathcal{V}\}$ of $Z$ in $X$ thus there exist $\mathcal{U}'\subseteq\mathcal{U}$ such that $|\mathcal{U}'|<ℵ_0$ and $Z\subseteq\bigcup\mathcal{U}'$ and so $\mathcal{V}'=\{U\cap Y:U\in\mathcal{U}'\}$ is an open and finite cover of $Z$ in $Y$ and so this prove that $Z$ is compact in $Y$.  It is my proof correct? if not, how prove the assertion? could be that if is false?  Could someone help me, please?

Let be X a topological space and let be $Z,Y\subseteq X$ such that $Z\subseteq Y$: so if Z is compact in Y then Z is compact in X.  To prove the assertion let be U an open cover of Z in X and we consider the open cover $\mathcal{U}'=\{U\cap Y:U\in\mathcal{U}\}$ of $Z$ in $Y$ -indeed $Z\subseteq\bigcup\mathcal{U}=\bigcup_{U\in\mathcal{U}}U\rightarrow Z=Z\cap Y\subseteq(\bigcup_{U\in\mathcal{U}}U)\cap Y=\bigcup_{U\in\mathcal{U}}(U\cap Y)=\bigcup\mathcal{U}'$- thus there exist $\mathcal{U}''\subseteq\mathcal{U}'$ such that $|\mathcal{U}''|<ℵ_0$ and $Z\subseteq\bigcup\mathcal{U}''$ and so $\mathcal{U'''}=\{U\in\mathcal{U}:U\cap Y\in\mathcal{U}''\}$ is an open and finite cover of Z in X -indeed $|\mathcal{U}'''|=|\mathcal{U}''|<\aleph_0$ and $Z\subseteq\bigcup\mathcal{U}''\subseteq\bigcup\mathcal{U}'''$- and so this prove that $Z$ is compact in $X$.  It is my proof correct? if not, how prove the assertion? could be that if is false?  Could someone help me, please?


i am new on Blender and i have been modeling a sofa with pilows. Just wanted to create some creases on pillows. But when i try that, it sculpts as pixeled and two lines although i want it one unlike in some tutorials. I put the following picture to show it. How can i fix it ?

So, I am extremely new to blender, I am going to say outright. I have tried to fix this, but i can't seem to find any option that would fix the problem. When I sculpt on an object, it directly mirrors it, even though i have not enabled the mirror function, let alone touch it. I have double checked to make sure mirror wasn't on and it wasn't. and so on and so forth. I pretty much haven't changed any options or anything. if you could help me figure this out, that would be nice.


I have a few arrows that I created for usage in math mode. I recently found out that the arrows seem to have a white background (between the two lines). This is a problem for me as I have a gray background in some parts of my document (e.g., definitions have a gray box as background). I created these arrows mostly by copying stuff from the internet and modifying the arrows until they roughly looked the way I had in mind. However, I don't understand how I can modify the background color (the part between the lines). Is it somehow possible to have a transparent background (instead of white)? Thank you for your help! \documentclass{scrartcl}  \usepackage{tikz} \usepackage[utf8]{inputenc} \usepackage{xcolor}  \usetikzlibrary{calc,arrows,decorations.pathmorphing}  \newcommand{\xRightarrow}[1]{     \mathrel{         \begin{tikzpicture}[baseline= {( $ (current bounding box.south) + (0,-0.5ex) $ )}]             \node[inner sep=.5ex] (a) {$\scriptstyle #1$};             \path[draw,implies-,double distance between line centers=2pt] (a.south east) -- (a.south west);         \end{tikzpicture}     } }  \newcommand{\xTwoheadrightarrow}[1]{     \mathrel{         \begin{tikzpicture}[baseline= {( $ (current bounding box.south) + (0,-0.5ex) $ )}]             \node[inner sep=.5ex] (a) {$\scriptstyle #1$};             \path[draw,implies-,double distance between line centers=2pt] (a.south east) -- (a.south west);             \path[draw,implies-,double distance between line centers=2pt] ($ (a.south east) + (-0.079,0) $)--($ (a.south east) + (-0.08,0) $);         \end{tikzpicture}     } }  \newcommand{\xRightsquigarrow}[1]{     \mathrel{         \begin{tikzpicture}[baseline= {( $ (current bounding box.south) + (0,-0.5ex) $ )}]             \node[inner sep=.5ex] (a) {$\scriptstyle #1$};             \path[draw,implies-,double distance between line centers=1.5pt,decorate,decoration={zigzag,amplitude=0.7pt,segment length=1.2mm,pre=lineto,pre length=3pt}] (a.south east) -- (a.south west);         \end{tikzpicture}     } }  \begin{document}  \pagecolor{gray}  \noindent $\xRightarrow{abcde}$ \\ $\xTwoheadrightarrow{abcde}$ \\ $\xRightsquigarrow{abcde}$   \end{document}  The corresponding output looks as follows:

How to remove the core color in double line in tikz ?    \documentclass[margin=10pt]{standalone} \usepackage{tikz} \usetikzlibrary{backgrounds} \usetikzlibrary{arrows}  \begin{document} \begin{tikzpicture}[show background rectangle, background rectangle/.style={fill=lightgray}]  \draw[thin,double,-implies] (0,-0.8,0) -- (0,-1.9,0) ; \end{tikzpicture} \end{document}


Spider-Man can spin web from his wrist, and once he does so, uses it to swing. then he releases it and it is hanging all around the city buildings. So my question is: after how much time does Spider-Man's web decompose?

Especially if he is not using his  but .   Also what happens to the web that he leaves behind? Does it decay after certain time or lose it stickiness and drops off?


I have a simple html dropdown, I wants to use jQuery if possible to display all the options if this control has the focus(as if the user click on the dropdown). I have tried jQuery trigger(), click(), to avail.     <select id="single">     <option>Single</option>     <option>Single2</option>   </select>

How can you programmatically tell an HTML select to drop down (for example, due to mouseover)?


I have a problem that the regular text of the article adds extra margins to the specified margins. To make it more clear, whatever I do, the text is "narrower" than what I specify with the geometry package. The main problem is that the algorithm environment and footnotes respect the specified margins, so they look wider than the text. It is somewhat intriguing that when I change the document class from article to report, the problem goes away. However, I need to use article. Any ideas? Here is an example (I added showframe so that it is clear what is happening):  \documentclass[11pt]{article}   \usepackage{amsmath,amsfonts,graphicx,amssymb} \usepackage{algorithm} \usepackage[noend]{algpseudocode} \usepackage{url} \usepackage{cite} \usepackage{enumitem} \usepackage[colorinlistoftodos]{todonotes} \usepackage{dsfont} \usepackage{geometry} \usepackage{blindtext} \usepackage{showframe}  \geometry{   width=6.8in,   height = 9.2in,   left=0.9in,   top=0.9in } \let\proof\relax \let\endproof\relax \usepackage{amsthm}  \makeatletter \def\thm@space@setup{\thm@preskip=0pt \thm@postskip=3pt} \makeatother  \newtheorem{theorem}{Theorem}[section] \newtheorem{lemma}[theorem]{Lemma} \newtheorem{proposition}[theorem]{Proposition} \newtheorem{claim}[theorem]{Claim} \newtheorem{fact}[theorem]{Fact} \newtheorem{corollary}[theorem]{Corollary} \newtheorem{definition}[theorem]{Definition} \newtheorem{observation}[theorem]{Observation} \newenvironment{proof-sketch}{{\bf Proof Sketch:}}{\hfill\rule{2mm}{2mm}} \newenvironment{note}{\noindent\textbf{Note:}}  \makeatletter \newenvironment{proofof}[1]{\par  \pushQED{\qed}%  \normalfont \topsep3\p@\relax  \trivlist   \item[\hskip\labelsep     \bfseries Proof of #1\@addpunct{.}]\ignorespaces }{%   \popQED\endtrivlist\@endpefalse } \makeatother  \title{Title} \author{ Author }  \date{}  \begin{document} \maketitle \abstract{}  \thispagestyle{empty} \newpage  \section{Introduction} \setcounter{page}{1} \pagestyle{plain} \blindtext\footnote{\blindtext} \end{document}

In the article class, it seems that using the abstract environment has an effect to the rest of the document. More precisely, it seems that it redefines the \linewidth, which equals \textwidth without abstract, is smaller with the abstract. My feeling is that \linewidth is redefined for the abstract environment, but the value is not reseted at the end of the abstract.  Here is a minimal example:  \documentclass{article} \begin{document} \abstract{This is an abstract. This is an abstract.}\bigskip  This is text. This is text. This is text. This is text. This is text. This is text.\\  \rule{\textwidth}{3em} \rule{\linewidth}{3em} \end{document}   The output is not the same if you comment the \abstract line or not.  Do you have the same problem as I do when you compile (if not, I will upload some PDF files to show)? Is this a (known) bug in LaTeX2e? How can we circumvent the problem?  Note: I compile with the pdflatex command, and I use pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian).


Incidentally, I found     $$\frac{1}{\sum_{n=1} \frac{1}{x^{n}}} = (x-1)$$  where $x\ge 2$.  Please direct me to how others have developed the relationship. My computer cannot compute more than X = 500,000 so I just infer that it is always true.

Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


I recently switched to linux full time from windows and while I was trying to update my npm package using n, I got the new binaries in /usr/local/bin and previous version was in /usr/bin. So, it was always picking the previous version.  As per recommendation by a fellow user, I used hash-r command and it worked. But, I don't know what it did.   It would be very helpful if someone could explain its internals to me.

man echo works. but out of curiosity, does echo have something similar to a --help flag/parameter?


I have an external USB drive, formatted as NTFS. It has started to fail, and has a number of bad sectors. I have been able to recover most of the data, but one directory was giving errors so I ran CHKDSK /f on the disk.  CHKDSK did not complete, failing because it ran out of space (there was at the time around 40gb free out of 500gb). After it ran, the problematic directory became empty, and CHKDSK left a found.000 file in the root. I think normally this would be a directory full of .chk files, but in this case the found.000 file itself is corrupt - in info screen, it shows a "size" of "17356456 bytes (,.))/0(,0 bytes)" but "size on disk" of 4.00kb. So even the actual size can't be figured out by the OS.  I have now deleted some additional files to give the disk more space, but CHKDSK will not complete (it hangs). I'm wondering if there is some way I can un-corrupt this found.000 file, as I suspect it will contain the missing files from the directory in question.  Any ideas?

Just discovered I have gotten a FOUND.000 folder on my usb drive. I guess from running chkdsk once. It has three files in it:   FILE0000.CHK FILE0001.CHK FILE0002.CHK   What exactly can I do with these files? What are my options? Are they lost files? Are they garbage? Can I use them for anything at all? Or will I just have to delete them?


I have that $$5\mid 8^n - 3^n$$  The first thing I tried is vía Induction:  It is true for $n = 1$, then I have to probe that it's true for $n = n+1$  $$5 \mid 8(8^n -3^n)$$ $$5 \mid 8^{n+1} -8\cdot3^n$$ $$5 \mid 3(8^{n+1} -8\cdot3^n)$$ $$5 \mid 3\cdot8^{n+1} -8\cdot3^{n+1}$$  After this, I don't know how to continue. Then I saw an example about a property: $$(a+b)^n = am + b ^ n$$ with $m = a + 2b$ or the number it represents.  $$5 \mid 8^n -3^n$$ $$5 \mid (5+3)^n -3^n)$$ $$5 \mid 5m + 3^n - 3^n)$$ $$5 \mid 5m$$  So, $d \mid a$ only if $a = kd$. From this I get that $5 \mid 5 m$.  My questions:  1) Is the exercise correct?  2) Could it have been resolved via method 1?  Thanks a lot.

I did some mathematical induction problems on divisibility   $9^n$ $-$ $2^n$ is divisible by 7. $4^n$ $-$ $1$ is divisible by 3. $9^n$ $-$ $4^n$ is divisible by 5.   Can these be generalized as $a^n$ $-$ $b^n$$ = (a-b)N$, where N is an integer? But why is $a^n$ $-$ $b^n$$ = (a-b)N$ ?  I also see that $6^n$ $- 5n + 4$ is divisible by $5$ which is $6-5+4$ and $7^n$$+3n + 8$ is divisible by $9$ which is $7+3+8=18=9\cdot2$.  Are they just a coincidence or is there a theory behind?  Is it about modular arithmetic?


I have always wondered how does Mystique's transformation works.   Please spare me as I don't read many Marvel comics, just those random ones which I can get.  When Mystique transforms to male characters, does she also inherit the bodily functions? In X-Men:DoFP, we saw that she cries when morphed as Trask. Since male and female tear glands function similarly (at least what I assume, never studied Biology), it must not be an issue. But what about other parts that act as outlet for some bodily liquids which differ in functioning due to gender differences? Also does Mystique inherit target's injuries and pain along with it?  If Mystique morphs into a pregnant lady she sees, will she also replicate the baby inside. If Yes, when she transforms back to original form, will she terminate the baby?

When Mystique shape-shifts, she looks like the person she wants to imitate with their clothes on.  Now, if she removes these clothes and puts them away and then returns to her original form, do the clothes stay there? If so, isn't she violating one of the fundamental laws of physics, that something can't be created from nothing?


$$\lim_{n\to\infty}\large n(a^\frac{1}{n}-1) 0$$ $$a>0$$ is the problem. So far what I tried was transforming $$(a^\frac{1}{n}-1)$$ by using the formula $x^n-1 = (x-1)(x^{n-1} + x^{n-2} +...+1)$ but I fail to see how this would help me in this instance, or I just may be doing it wrong because it's the nth root that is giving me problems. Any help would be appreciated

How to compute the following limit?  $\lim\limits_{n\to\infty} n·(\sqrt[n]{a}-1)$  We know that it's got something to do with $\ln$ or $\exp$.  We know that $\lim\limits_{n\to\infty} \sqrt[n]{a} = 1$ but it seems to not to be true that therefore $\lim\limits_{n\to\infty} n·(\sqrt[n]{a}-1) = \lim\limits_{n\to\infty} n·(1-1) = 0$.  What we know is  $\lim\limits_{n\to\infty} (1-\frac{1}{n})^n = \lim\limits_{n\to\infty} (1 + \frac{1}{n})^n \lim\limits_{n\to\infty} (1-\frac{1}{n})^{n+1} = e$  and  $\lim\limits_{n\to\infty} (1+\frac{x}{n})^n = \exp(x)$


I am searching this question on Google but I couldn't find any suitable results. Now I am posting this question on Stack Exchange as my last options. As we all know that Google is the leading door of high traffic towards a site, I want to make my website top ranking on google. I have already submitted it to google and i i also use proper meta tags. What are the factors that make a site topranking and how to make our site pop up top in google? Please someone help me guys. Thanks In advance :)

What are the best ways to improve a site's position in the Google search results?


For $n \ge 2$  give example of a bijective continuous map $f: \mathbb R^n \to \mathbb R^n$ whose inverse is not continuous ; example of such a function is also an example of

Looking at the definition of an homeomorphism, this question came to my mind.


Basically, I came back to my computer after leaving it on and logged in (it locks itself after some time), and realized that it had restarted in the time I was away. Shortly after login and my on-start programs started loading, it flashed two installation screens of Visual C++. I checked the event log and see that I have a few events associated with this - the most alarming being that System Restore was turned off. I know that malware is known to do this - but can find nothing suspicious about the Visual C++ packages installed. I also checked my Windows Update history and I see that an update was performed today, with the installation of the Windows Malicious Software Removal Tool. Not sure if this is related. I ran MalwareBytes Pro and it found nothing. I had a threat on my computer a few days back and have since quarantined and deleted it, but I'm still a bit uncertain. Having my computer restart unprompted (didn't even give me a warning) is unsettling, but add the bit of flashing installation screens, mixed with the prior threat detected by MWBP, and my heart's moving a bit fast right now. Is there anything I need to be concerned about here? Thanks!

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


Consider: $324\cdot x\equiv y\pmod {360}$, for x,y>0 Is it true that for every y of the form $2^j\cdot 3^k$, with j,k some integers (that is for y 3-smooth), there is always a integer $x$ satisfying the modular equation? Are there solutions for which y is not a 3-smooth number?

Isn't finding the inverse of $a$, that is, $a'$ in $aa'\equiv1\pmod{m}$ equivalent to solving the diophantine equation $aa'-mb=1$, where the unknowns are $a'$ and $b$? I have seem some answers on this site (where the extended Euclidean Algorithm is mentioned mainly) as well as looked up some books but there is no mention of this. Am I going wrong somewhere or is this a correct method of finding modular inverses? Also can't we find the Bézout's coefficients by solving the corresponding diophantine equation instead of using the extended Euclidean Algorithm?


I was learning about inception module from deeplearning.ai by Andrew Ng, wherein we use 1x1 convolution to reduce computational cost. for example, if we directly apply 5x5 convolution we need to multiply for about 120M times whereas by introducing 1x1 convolution we reduce it by the factor of 10.  My question what effect does this have on the feature maps that are being learned or will the quality of feature maps differ if we had not used 1x1 convolution.  below is the screenshot of how we reduce multiplications from 120M to about 12M:

I am currently doing the Udacity Deep Learning Tutorial. In Lesson 3, they talk about a 1x1 convolution. This 1x1 convolution is used in Google Inception Module. I'm having trouble understanding what is a 1x1 convolution.  I have also seen  by Yann Lecun.  Could someone kindly explain this to me?


When the length of the text prior to an equation environment approaches \textwidth, hyperref adds an extra vertical space, as illustrated by the following snapshot:    The corresponding code is  \documentclass[12pt,fleqn]{article} \usepackage{a4} \usepackage{amsmath} \usepackage{hyperref}  \textwidth = 16cm \setlength{\parskip}{1.5ex plus0.5ex minus0.5ex} \setlength{\parindent}{0em}  \begin{document} Suppose $\vec{T}$ is a lower triangular matrix. Then $\vec{T}^{T}$ is upper triangular. By Lemma 2.23921, \begin{equation}     \det(\vec{T}) = \det(\vec{T}^{T}) = [\vec{T}]_{11}[\vec{T}]_{22}\dotsb[\vec{T}]_{nn}, \end{equation} as required. \end{document}   Note that it seems to affect the equation environment only.  Since there is no apparent way to predetermine the occurrence the problem in the source code,  I will have to manually scan the output text for the affected parts and replace equation with other math environments, such as gather, to circumvent the problem; clearly, this approach is suboptimal.  So, the question is, why does it only affect the equation environment but not other math environments? Is there a way fix this?

When the fleqn option is used, the vertical spacing before an equation placed right after a "long" text line (exactly \linewidth I would say) is improperly set up. See below:    From the mathmode user guide, this could probably be fixed through the \topsep length. Is it the right way to proceed? The problem is reproduced by the code below:  \documentclass[12pt,fleqn]{book} \usepackage{amsmath} \usepackage{hyperref} \begin{document} \chapter{plo} \section{plo} eoiu oieu oeiuoe ueoi ueoi ueoiu eoiu oeu oe iupaêio umùaeoiuaem oeiu eoiu eoiu oeee. eoiu oieu oeiuoe ueoi ueoi ueoiu eoiu oeu oe iupaêio umùaeoiuaemm \begin{equation} \cos\pi=-1 \end{equation} eoiu oieu oeiuoe ueoi ueoi ueoiu eoiu oeu oe iupaêio umùaeoiuaem oeiu eoiu eoiu oeee. eoiu oieu oeiuoe ueoi ueoi ueoiu eoiu oeu oe iupaêio umùae \begin{equation} \cos\pi=-1 \end{equation} \end{document}   There is something wrong involving hyperref, amsmath, and fleqn. Removing one of those removes the problem.


I used  to clean the screen of my MacBook Air. I later read that this will leave a film on the screen, which seems to be the case when holding the screen up against the light.  How can I return my screen to the state it was before using the chemical? (Preferably without purchasing additional or hard-to-obtain products.) Or is my screen permanently ruined?  The printing on the bottle very informatively lists the following ingredients:   De-ionized water Proprietary polymers

I try to clean my mid-2015 Macbook Pro with Retina display by wiping the screen with a damp cloth and then immediately drying.  However, there seems to be left some residue/streak marks, which look very oily. Sometimes these disappear after a few minutes, but they are still very unsightly, and a bit worrying (is there something wrong with my screen?)  I'm wondering if there are other cleaning techniques which avoid this issue, or whether this is completely normal behaviour.  Thank you!


How do I change the order of columns in a table? I have too many rows and doing this manually would be a horrible pain.  A MWE to get us going (let's get rid of Yoda!):  \documentclass{article}  \begin{document}  \begin{table}     \begin{tabular}{c c c c}         \hline \hline         this & in & order & is \\ \hline\hline         1    & 3  & 4     & 2  \\         a    & c  & d     & b  \\         \hline     \end{tabular}  \end{table}       \end{document}

What is the best way of editing an existing LaTeX table? I need to swap the order of two columns and can't think of an efficient way of doing this.  My table is a long creature of the following structure:  A &     -0.523 &      26.94 &     0.8243 &     0.0000 &     -12.67 \\ B &     -0.614 &      30.02 &     0.8509 &     0.0000 &     -13.12 \\ C &     -0.630 &      32.92 &     0.9254 &     0.0000 &     -21.45 \   I need to change the values so that it is:   A &     26.94 &      -0.523 &     0.8243 &     0.0000 &     -12.67 \\ (etc)   The thoughts that I had were to import it into Excel and to drag columns around, and then use the concatenate() function to produce the number & number structure. I feel like there might be a better way of doing this that I am unaware of.


I recently updated to windows 10. When I boot to windows from grub I get the error: "Windows Failed to Start A Recent Hardware or Software Change Might Be The Cause." Changing the name in /boot/grub/grib.config to "windows 10" from "windows 7" didn't fix it. The only way to boot to windows is to switch to bios, and manually boot to the drive that windows is on. This is inconvenient and I would like to know how to update grub to reflect the change to windows 10. I tried Ubuntu Boot repair, but it again set my boot option to "windows 7." I'm not sure which logs to look at.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


i have a problem whit c#, please someone convert this javascript function to c#.  function mycrc(str) {         var c;         var crcTable = [];         for(var n = 0; n < 256; n++){             c = n;             for(var k = 0; k < 8; k++){                 c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));             }             crcTable[n] = c;         }        var crc = 0 ^ (-1);     for (var i = 0; i < str.length; i++ ) {         crc = (crc >>> 8) ^ crcTable[(crc ^ str.charCodeAt(i)) & 0xFF];     }     return (crc ^ (-1)) >>> 0; }

How do I calculate the CRC32 (Cyclic Redundancy Checksum) of a string in .NET?


I am a complete beginner in Ubuntu I need little help. After dual booting, my system with Windows and Ubuntu I install the google chrome using the terminal window command with some source on the web. The chrome is working fine.  When I use the ls command in Ubuntu 19.10 to get the list of all the directories, I get the following result:   anil@anil-HP-15-Notebook-PC:~/Desktop$ ls   google-chrome-stable_current_amd64.deb   Then I tried ls -a and I get the following result  anil@anil-HP-15-Notebook-PC:~/Desktop$ ls -a .  ..  google-chrome-stable_current_amd64.deb   Where I am going wrong? please help me. Thanks.

Doing "ls" gives me absolutely no response. No "command not found", no "permission denied", absolutely nothing. I'm really confused. Please help.  Info: Running Ubuntu Server 16.04.4 on a Digital Ocean VM, 1 GB, 1 vCPU.


I had my CF card reader die on me a few times (i.e., it suddenly stopped working: instead of being recognised, and then allowing me to access the CF card, it was "cycling", i.e., appearing/disappearing from Windows). So I decided to do a backup using an USB cable.  What happened:   My PC had [historically] the EOS utility installed For personal reasons (mostly: special workflow, and avoiding the clumsy download interface) I wanted to just copy the files over, bypassing the EOS utility However, when plugging the USB cable between the 5DMkII and the PC, it only got recognised as the camera, and when exploring that I could see each image twice in JPEG (one with extension, the other without, but both JPEG, whereas I know that on the CF one is .JPG, and the other .CR2, larger and with more details). I tried, however, to copy both, each in separate directories (as they had the same name), but it really ended up as two identical files each time, as if it "hides" the raw and instead shows another instance of the associated JPEG file.    Example: using a CF reader I would get IMG_0001.JPG and IMG_0001.CR2, the 2nd raw and much larger in details and size. Via cable I saw "IMG_0001" and "IMG_0001.JPG", both ending up as "IMG_0001.JPG" on my computer, and no raw file...  How can I retrieve the .CR2 files? (if possible, without uninstalling the EOS utility! But still bypassing it... I.e., how do I use a USB cable to access the files as if by a card reader?) (Should I boot on some linux boot CD and try from there?)

I can't download photos from my new Canon 6D via the USB cable. Cable is connected, but no new drive is detected in the system. Looks like Windows doesn't see a new device at all. How do I troubleshoot this problem?


Usually we use     In the morning      At night   Both of them represent time but why do we use different prepositions?

I have found the following usage of "on", "at" and "in" on the internet. Is there any other exception and/or rule for that?  Prepositions of Time Use in for  Months: in April / in September / in that month Seasons: in (the) summer / in (the) winter Years: in 1332 / in 1984 / in that year / in the next year Long Period(s) of Time: in former century / in 90's / in the Ice Age / in the past / in the future  Exceptions: in the morning / in the evening Use at for  Time: at 8 o'clock / at 9:30 / at bedtime / at sunset / at dinnertime / at 5:33:10 AM  Exceptions: at Christmas (= during the Christmas holidays but not necessarily on December 25th) / at Easter  / at noon / at night / at the weekend / at the present time / at the moment Use on for  Days: on Monday / on Friday / on Christmas Day (= on December 25th) / on Easter Sunday / on Independence Day Dates: on February 18th / on her birthday / on 21 March 2015 / on  Notice:  We have in the morning and on Monday but we say on Monday morning, not in Monday morning, and so on. When we say last, next, every, this we do not also use at, in, on: She runs next Tuesday. (not on next Tuesday) / He leaves us every Easter. (not at every Easter) / I See you this evening. (not in this evening) Look at these examples for the combination of times in a sentence: We will meet next week at six o’clock on Monday. / I heard a funny noise at about eleven o’clock last night. / It happened last week at seven o’clock on Monday night.   Look at  as well which says:  This all hints at a coherent metaphor: hours and other short periods of time are places; days are surfaces; months and longer time periods are containers.


I am using the KOMA scrartcl-class  \documentclass[listof=totoc,toc=sectionentrywithdots,DIV=14]{scrartcl}   Is there a way to change the font-style of the part, section, subsection and subsubsection globally?

How to change the default KOMA-Script font that is used for chapter/section headings etc. to the Computer Modern font that is used in text body?


How to prevent a bookmark entry in PDF file, for a numbered section included in table of contents? I wanted to use \section{test}, to have a numbered section, and with an entry into TOC; but I'd like to remove the automatic bookmark entry in pdf file.

I'm forced to use a third-party document class that somewhat messes up the bookmarking done by hyperref (and the bookmark package): a spurious bookmark appears for 'author' (so I guess the package implements 'author' using a sectioning macro). Therefore, I would like to be able to disable bookmarking temporarily, in my case before the \maketitle command, and reenable it afterwards.   Is this possible using hyperref, or the bookmark package. (I'm currently using the latter to partly overcome the problem, using \bookmarksetup{startatroot}.)


Should I choose an other metric or is the way to handle this problem?

MAD = Mean Absolute Deviation MSE = Mean Squared Error  I've seen suggestions from various places that MSE is used despite some undesirable qualities (e.g. , which states on p8 "It is commonly believed that MAD is a better criterion than MSE. However, mathematically MSE is more convenient than MAD.")  Is there more to it than that? Is there a paper that thoroughly analyzes the situations in which various methods of measuring forecast error are more/less appropriate? My google searches haven't revealed anything.   A similar question to this was asked at , and the user was asked to post on stats.stackexchange.com, but I don't think they ever did.


Edit: I think my problem is different from the one that is similar because when I tried to split my declaration of Seat it gave me the non-static error.  I have a program to write for a class, and I created a object called Seat. However, when I try to reference it in main, it says I have a null pointer error. When I declare every item in the object array it says I can't reference the object seats from a non static standpoint. I tried a whole bunch of other questions on STackOverflow but I couldn't get any of them to work. This is what I have so far:  @SuppressWarnings("unchecked") public static void main(String[] args) throws Exception{      File file = new File("Customers.txt");     Scanner input = new Scanner(file);      Customer[] airlinecustomer;     airlinecustomer = new Customer[40];     Seat[] seats = new Seat[40];        for(int i = 0;i < 40;i++) seats[i] = new Seat();      seatssold = seatssold + input.nextInt();      for(int i = 0;i < seatssold;i++) {          airlinecustomer[i].firstname = input.next();         airlinecustomer[i].lastname = input.next();         airlinecustomer[i].DOB = input.next();         airlinecustomer[i].email = input.next();         airlinecustomer[i].address = input.next();         airlinecustomer[i].telephone = input.next();         airlinecustomer[i].seat = input.nextInt();          seats[i].customer = i;         seats[i].available = "S";      }      //for(int i = 0;i < 40;i++) if(seats[i].available != "S") seats[i].available = "U";    }  public class Customer {      private String firstname;     private String lastname;     private String DOB;     private String email;     private String address;     private String telephone;     private int seat;          public Customer(String firstname,String lastname,String DOB,String email,String address,String telephone,int seat) {              this.firstname = firstname;             this.lastname = lastname;             this.DOB = DOB;             this.email = email;             this.address = address;             this.telephone = telephone;             this.seat = seat;         } }  public static class Seat {      static String available;     static int customer;          public Seat(String available,int customer) {              this.available = available;             this.customer = customer;         } }   }  I'm sorry if this is confusing but I just have no idea what to do, I have only been coding for a few months.  Thanks so much :)

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


Is there anyway for to bring installed programs from one ubuntu pc to another, without installing it from the Software centre? I am having problems trying to install MyPaint on my desktop, though there was no problem on my netbook.

I am running Ubuntu 13.04 on a 250 GB hdd. This HDD has developed bad sector and I received replaced drive from Manufacturer. I am also running a RAID1 using mdm.  I want to move the existing setup to new hard drive.  Can someone please give suggestions.   Thanks for your answers.  Cheers.


I am trying to access label in a component(Lightning web component).  import greeting from '@salesforce/label/c.xxxx; import greeting from '@salesforce/label/c.yyyy; ...   I want to access all labels in one import.  So is it possible? Reason is: one of my component have lot of messages which we need to import. we want to avoid multiple import line for label in my component.  I was following salesforce article but didn't get there:        Or if is there other way around, if we can remove multiple time import?

Is there a way to load every label data and every SObject description data using only Javascript without any Apex Server-side code?  How do I import * from @salesforce/schema or @salesforce/label?  I am looking for a way to get all labels or all SObject describe information details to retrieve in LWC at once.  I can see that such syntax is provided by ES6 and is used widely by Salesforce itself, however, it is not possible to use the following syntax in LWC:   import * as schema from '@salesforce/schema'   import * as label from '@salesforce/label'   or this syntax  import {label, schema} from '@salesforce';   since both versions generate error     LWC1512: Missing resource value for @salesforce"   or      LWC1512: Missing resource value for @salesforce/label   Is there a way to load every label data and every SObject description data using only Javascript without any Apex Server-side code?  By the way, if we look as Salesforce Playground we could notice that   the same syntax is used to import everything from lwc  import * as Engine from 'lwc';   however, if we try to insert such line into any of Lightning Web Component, we would receive the following error     LWC1001: Invalid import. Namespace imports are not allowed on "lwc",   instead use named imports "import { LightningElement } from 'lwc'"   or   LWC1517: Invalid LWC import


Do there exist naturaln numbers $a, b, n \in \mathbb N$ such that   $$\sqrt{n}+\sqrt{n+1}<\sqrt{a}+\sqrt{b}<\sqrt{4n+2}?$$   One can easily see that both $a, b$ can't be perfect squares, because $$(\sqrt{n} + \sqrt{n+1})^2 = 2n +1 + 2 \sqrt{n^2+n} < 4n+2,$$ which after trivial transformations is equivalent to $$4n^2+ 4n < 4n^2 + 4n +1.$$

Show that for any $n\in\mathbb{N}$ there does not exist natural numbers $x,y$ such that $$\sqrt{n} +\sqrt{n+1} <\sqrt{x} +\sqrt{y} <\sqrt{4n+2}.$$


Having difficulty in arcmap 10.5 changing projections from GCS_North_American_1983 WKID: 4269 Authority: EPSG to NAD_1983_Ontario_MNR_Lambert WKID: 3161 Authority: EPSG. Every attempt constantly displays the newly projected data outside the view extent of the current Arcmap layer even with the new projection. To view the new projected data I have to use "zoom to layer"  then zoom to layer back to the data in my layer.

I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I cannot figure out how to make the other 3 show up at once on top of each other.  Before I opened ArcMap, I used ArcCatalog where I right-clicked 3/4 of the shapefiles and  clicked Properties → Coordinate system → Import and then clicked on my Trees layer, which has the coordinate system I want the other 3 to have. But when I opened ArcMap the 4 layers did not overlap, nor could I move them above or below each other.


I read this story around 1975. The main character traveled with some traders to a planet that had no metal, and that was being prevented from having any metal (I don't recall why). The planet's inhabitants were very ingenious in creating technology without metal. The part that sticks in my mind is when the main character went to a market with one of the traders, where they were attacked by the locals. The trader had obtained a local firearm which was almost entirely made of clay. The firearm's "trigger" worked a pump similar to a water gun, which built up air pressure inside the firearm. The firearm contained powdered coal, and striking a spark inside the pressurized firearm ignited the dust and propelled a dart.   I don't recall much of the plot, but I have always remembered that description of the firearm.

Protagonist (named Alan?) is a novice in a monastic order of interstellar translators/lawyers/negotiators.  The story covers his first position, hired out on a trading mission to a civilization without native metals. During the mission, he learns that the official non-interference and non-violence positions of his order are not shared by (some of?) its leaders.  References to and translated quotes from Machiavelli are used often.


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

Suppose that $n \in \mathbb{N}$ is composite and has a prime factor $q$. If $k \in \mathbb{Z}$ is the greatest number for which $q^k$ divides $n$, how can I show that $q^k$ does not divide ${{n}\choose{q}}$?  Clearly, since $$ {{n}\choose{q}} = \frac{n!}{(n-q)!q!} = \frac{n(n-1)(n-2) \dots (n-q+1)}{q!} $$ So it suffices to show that, no element of the set $$ \left\{ n-1, n-2, \dots, n-q+1 \right\} $$ is divisible by $q$, which is clearly true, but I am unsure of how to show this rigourously.


I'm new with Apex. I'm downloading images from web with Apex that i'd like to add in Files. Already i'm just adding images to Attachment.  //Download image Http h = new Http(); HttpRequest req = new HttpRequest(); req.setEndpoint(linkImg); req.setTimeout(60000); req.setMethod('GET');  HttpResponse res = h.send(req);  Blob bodyImg = res.getBodyAsBlob();  //Add image to Attachment Attachment att = new Attachment(Name = nameImg, Body =             bodyImg, ContentType = 'image/png',            ParentId=parentid); insert att;   Is there a way to add document directly in Files or convert/link automatically Attachment to Files ?

From the Chatter tab I can go to 'Files' and then upload a file without attaching it to anything.   I am wanting to know if there is a way to achieve the exact same thing via Apex?


If you delete a question that was modifying your reputation count (+/-), close the site page and come back, you will have a nice surprise. Your rep count will show you all the reputation points you made today.     That was the point of my test post btw. Reproduced again:

In  I see from time to time the indicator kind of resetting itself. It does not know anymore that I already "confirmed"/"noticed" the new rep. Then I see something like this for instance:  or smaller numbers. But I am sure I did not gain any or so much rep since the last time I clicked on that number. This happens whenever I delete a post of mine. BTW my internet connection is excellent and the websocket connection is absolutely stable.


In The Hobbit, there is a brief mention of giants playing games by tossing enormous boulders whilst the twelve dwarves, Gandalf, and Bilbo make their way through a pass in the Misty Mountains. Where did giants come from? I do not recall them from The Silmarillion. Does Tolkien ever address their origins elsewhere?

I was playing LOTR War in the North the other day. Despite its inaccuracy, there was one part where I had to fight a stone giant. I don't recall this from any of the books I've read, which are numerous. So I would like to know.   Where did giants come from? Are they Maia spirits like those of the Eagles and Ents? Do they originate from Melkor (Morgoth)?


In Episode II, they showed that stormtroopers were a request from Sifo-Dyas to create the clone army based on Jango Fett.  Why are the clones not being used in the First Order?

Reading this article about , my nerd-rage started flaring as they claimed that Stormtroopers were still Fett-Clones 20 years after the rise of the Empire.  As I started thinking about it, I realized that everything I had read saying that Modern-Day Stormtroopers not being clones was from the EU - C Level books or games.   One of the quotes often cited for backing the idea that the Stormtroopers are clones comes from Princess Leia:     Aren't you a little short for a Stormtrooper?   But through the movie, paying close attention, Stormtroopers are often shown to be slightly different heights. One even hits his head in the doorway while others walk through uninjured.                                  Is there any G Canon fully canon (non-Legends/Infinities) evidence to support the idea that Stormtroopers are, or are not still clones at the time of Episode IV?


There are lots of theorems and lemmas in my thesis which are being numbered continuously from start to end. I want the numbering to be like                  Theorem <>.<>. Same for lemmas and corollaries. I am using amsthm and the environments are defined like  \newtheorem{definition}{Definition} \newtheorem{lemma}{Lemma}   Is there any simple way to get chapter-wise numbering?

I've recently asked a question:   regarding working with chapters in tex. I have since learned that I must use documentclass report for the purposes of my document. However, now all of my Theorems, Corollaries, Remarks, and so forth are numbered "0.number.number" (with the first 0 never changing). I would like, at the very least, to understand how to make the first number denote the number of the chapter.  The current code I have is this:  \newtheorem{thm}{Theorem}[section] \newtheorem{rmk}[thm]{Remark} \newtheorem{qst}[thm]{Question} \newtheorem{prp}[thm]{Proposition} \newtheorem{hyp}[thm]{Hypotheses} \newtheorem{crl}[thm]{Corollary} \newtheorem{cnj}[thm]{Conjecture} \newtheorem{lem}[thm]{Lemma} \newtheorem{dff}[thm]{Definition} \newtheorem{clm}[thm]{Claim} \newtheorem{ntt}[thm]{Notation} \numberwithin{equation}{section}


I once asked for a solution to suppress vertical space right after the beginning of a proof environment; see the link (1) below. I use this quite heavily, it works very well.   I recently asked how to hide/display solutions in an exercise; see the link (2) below. It also works very well.   I now would like to construct a proof environment which allows for the hide/show feature. So exactly combining the two solutions of the above problems. I tried my best but I'm not a TeX expert... see below (I obtain: ./mini.tex:55: LaTeX Error: \env@proof@save@env undefined.)  \documentclass{scrartcl}  \usepackage{amsmath} \usepackage{mathtools} \usepackage{amssymb} \usepackage{amsthm} \usepackage{environ} \usepackage{ifthen}  \newboolean{showProof}% for showing proofs \setboolean{showProof}{true}% setting the switch  \newboolean{sol}% for solution environment \setboolean{sol}{true}% setting the switch  % proof environment which suppresses vertical space % see (1) http://tex.stackexchange.com/questions/66739/how-to-suppress-vertical-space-between-proof-environment-heads-and-itemize-envir \makeatletter \renewenvironment{proof}[1][Proof]{\par   \pushQED{\qed}%   \normalfont\topsep2\p@\@plus2\p@\relax   \trivlist \item[\hskip\labelsep   \sffamily\bfseries #1]\mbox{}\hfill\\*\ignorespaces }{%   \popQED\endtrivlist\@endpefalse } \makeatother  % solution environment which allows to show/hide of content % see (2) http://tex.stackexchange.com/questions/172404/solution-environment-via-true-false-switch?noredirect=1#172408 \makeatletter \NewEnviron{solution}[1][sol]{   \gdef\@tmp{#1}   \ifthenelse{\boolean{#1}}{\par\noindent{\sffamily\bfseries Solution}\par\noindent\BODY}{\ignorespaces} }[\ifthenelse{\boolean{\@tmp}}{}{\ignorespacesafterend}] \makeatother  % trial to define proof environment with the feature that content can be % shown/hidden (mix of the above two solutions) \makeatletter \RenewEnviron{proof}[1][showProof]{   \gdef\@tmp{#1}   \ifthenelse{\boolean{#1}}{%     \par\pushQED{\qed}%     \normalfont\topsep2\p@\@plus2\p@\relax     \trivlist\item[\hskip\labelsep     \sffamily\bfseries #1]\gdef\mycurrenvir{proof}\global\starttheoremtrue\mbox{}\hfill\\*\ignorespaces     \BODY}{\ignorespaces} }[\ifthenelse{\boolean{\@tmp}}{%   \gdef\mycurrenvir{\relax}   \popQED\endtrivlist\@endpefalse }{\ignorespacesafterend}] \makeatother  \begin{document} This is some statement we would like to prove: $\exp(i\pi)=-1$ \begin{proof}   This should be displayed if and only if showProof is set to true. \end{proof} \end{document}

Yes, you did read the title correctly!   I want to ignore everything that is between \begin{document} and \end{document} when I \input a file.  I thought that that would be very simple, just use :  \RenewEnviron{document}{}   But it turn out not be that easy. The MWE below yields the correct results:    but only with the comments intact. If you un-comment the commented lines then end up with:     LaTeX Error: \env@document@save@env undefined   Interestingly, ignoring this error one can continue past this, and still get the correct results. :-)  Notes:   I realize that in there can be other things in the preamble, so this is by no means a general solution. For the places where I need this functionality, the preamble only has \documentclass and two \input/\usepackage which loads all the .sty files needed so this will suffice for my needs.   Code:  \documentclass{article} \usepackage{environ} \usepackage{standalone}  \newtoks{\MyToken}  \usepackage{filecontents} \begin{filecontents*}{foo.tex}     \documentclass{standalone}     \usepackage{MyStandardPackages}      \MyToken={foo}  %   \begin{document} %       lots of text here % %       \SetSomeVarable{\SomeVar}{Some Value} %        %       \begin{SomeEnvironment} %           lots more stuff here as well %       \end{SomeEnvironment} %   \end{document} \end{filecontents*}  \MyToken={XXX}   \newcommand{\DisablePreamble}{%     \renewcommand{\documentclass}[2][]{}%  remove def'n of \documentclass     \renewcommand{\usepackage}[2][]{}%     ignore any \usepackage{} %   \RenewEnviron{document}{}% Ignore everything within the "document" environment. }%  \newcommand*{\ExtractMyToken}[1]{%     \begingroup% What happens in the group stays in the group!         \DisablePreamble%         \input{#1}%         \global\MyToken=\expandafter{\the\MyToken}%     \endgroup% }%  \begin{document} MyToken=\the\MyToken  \ExtractMyToken{foo}  MyToken=\the\MyToken \end{document}


My understanding is that the last change date(in /etc/shadow) is the number of days since 01/01/1970 that the password was changed, but I'm seeing numbers like 19708 which translate to 17/12/2023 (future).  How is it so?

man 5 shadow gives the following description of the third field in each line:  The date of the last password change, expressed as the number of days since Jan 1, 1970. The value 0 has a special meaning, which is that the user should change her pasword the next time she will log in the system. An empty field means that password aging features are disabled.  Does this refer to times in UTC or the local timezone? In particular, if I want to calculate comparable numbers using something like $(( $(date +%s) / 86400 )), do I need to pass date the -u option?


I need to get a value from a log file which I am getting using awk at the moment. I can get the number printing on the console but when I try to put that value into a new file nothing happens. Here is what i have    sshpass -p $PASSWORD ssh $USERNAME@$REMOTE_IP_ADDR  tail -F $INPUT_FILE |  awk '{ print $16 }' > $OUTPUT_FILE  //when command is run without > $OUTPUT_FILE i get my value eg 4000   This isnt a buffering issue because there is nothing being outputted to the file. A file gets created but the value isnt written to the new file. Also my value is always being overwritten as it is reading a line from another script which continuously replaces the line I read.  So i have fixed the problem I was having. The solution was assigning the command to a variable and the writing that variable to a file. I tried this before but  the issue I had was i had an extra space between my = sign and the command. Here is the working code    value=`sshpass -p $PASSWORD ssh $USERNAME@$REMOTE_IP_ADDR tail -n 1 $INPUT_FILE | awk '{ print $16 }'`          echo $value          echo $value > $OUTPUT_FILE  //will not work because of the space between "value= `sshpass"  //  value= `sshpass -p $PASSWORD ssh $USERNAME@$REMOTE_IP_ADDR tail -n 1 $INPUT_FILE | awk '{ print $16 }'`

I have a script which calls two commands:  long_running_command | print_progress   The long_running_command prints progress but I'm unhappy with it. I'm using print_progress to make it nicer (namely, I print the progress in a single line).  The problem: Connection a pipe to stdout also activates a 4K buffer, so the nice print program gets nothing ... nothing ... nothing ... a whole lot ... :)  How can I disable the 4K buffer for the long_running_command (no, I do not have the source)?


In this short story a scientist introduces a vaccine to stop children from aging so that parents never have to suffer the loss of watching them grow up and leave home. The main character is a mother who lives in an apartment complex and does almost the same thing everyday with her ageless child, always making sure he never is near books so he cannot learn to read and therefore grow up. A rebellious kid in the complex introduces this child to books and the story ends with the mother finding her child reading, and telling her he'll never leave her he promises.  I remember reading it in elementary school as part of a collection of shorts in science fiction.

Here's what I remember:  The boy is 5 years old, and has been for some time, because there's a bit in which he recalls turning 5 (celebrating his 5th birthday) many different times  There's a robot nanny in the apartment with him that he learned to disable so that he can hang out with the girl, who he isn't supposed to know. (In my mind the nanny bears somewhat of a resemblance to Muthr from the Wondla series... however I definitely read this story well before reading Wondla)  There's a neighbor girl who teaches him to read (I think she's like 9), and when they first meet she asks how old he is (5 is the last age at which growth/development can be successfully (and safely?) suspended) and he lies, saying that he's 6, but doesn't know why he does.  When a child whose aging process has been stopped learns how to read, they begin aging normally again, so the parents don't want them to learn to read.  The children who have stopped aging are kept apart from other children who grow normally-- they have separate playgrounds and the like  The injection/serum used to halt the aging process was developed by a scientist, who when he first shared his findings had a 5 year old son and injected him, then told the onlookers/potential buyers/other parents to come back in 20(?) years. When they did, their children were adults and no longer needed them or were ungrateful layabouts, and the scientist's son was still 5 years old, cute, needy, etc.  The main character has a discussion about how he wants to turn 6 with his parents and they agree but only because he's already learned to read and it's irreversible.  It's kinda dark and emphasizes the need that parents have to feel wanted. Please help! I remember it so vividly and I'd love to read it again!


This gif of some kind of handle being spun in zero gravity has been doing the rounds:    Why is it flipping back and forth? It seems odd that it flips, then seems to rotate around one axis in a reasonably stable manner before suddenly flipping about entirely.

See below gif image taken from .    Or see  about 30 sec in.    Is this a real effect?  Why does it seem to turn periodically? Can it be explained by classical mechanics alone? Is there a simple equation that models this behaviour?


Is following sum convergent?  $$\sum_{n=1}^{\infty} \frac{Sin^2(n)}{n}$$ Integral test, Dirichlet test doesn't apply. Any idea !

Does the series $$ \sum_{n=1}^\infty \frac{\sin^2(n)}{n} $$   converge?   I've tried to apply some tests, and I don't know how to bound the general term, so I must have missed something. Thanks in advance.


I am currently unable to find any wifi connections in Ubuntu. It works fine on Windows 10, however. Ive scoured the internet, but all of the posts are extremely old and i appear to be the only user with this problem. Im on the newest released version, 6.30.223.248 . Also, assume i have very little experience, because i have no idea what im doing.  I entered      sudo lshw -C network  *-network                   description: Ethernet interface    product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller    vendor: Realtek Semiconductor Co., Ltd.    physical id: 0    bus info: pci@0000:02:00.0    logical name: enp2s0    version: 15    serial: 2c:60:0c:81:c0:dd    size: 100Mbit/s    capacity: 1Gbit/s    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.1.252 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s    resources: irq:48 ioport:4000(size=256) memory:c4204000-c4204fff memory:c4200000-c4203fff *-network    description: Network controller    product: Qualcomm Atheros    vendor: Qualcomm Atheros    physical id: 0    bus info: pci@0000:03:00.0    version: 30    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress bus_master cap_list    configuration: driver=ath10k_pci latency=0    resources: irq:53 memory:c4000000-c41fffff   entering lspci -nnk | grep -iA2 net comes back with   02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 15) Subsystem: Acer Incorporated [ALI] RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [1025:098a] Kernel driver in use: r8169 Kernel modules: r8169  03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:0042] (rev 30) Subsystem: Lite-On Communications Inc Device [11ad:1806] Kernel driver in use: ath10k_pci   entering dmesg | grep ath returns   [    9.909508] ath10k_pci 0000:03:00.0: pci irq msi-x interrupts 8 irq_mode 0 reset_mode 0  [   10.152414] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/cal-pci-0000:03:00.0.bin failed with error -2  [   10.152427] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-5.bin failed with error -2  [   10.152430] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-5.bin': -2  [   10.152437] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-4.bin failed with error -2  [   10.152440] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-4.bin': -2  [   10.152447] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-3.bin failed with error -2  [   10.152449] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-3.bin': -2  [   10.152456] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-2.bin failed with error -2  [   10.152458] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-2.bin': -2  [   10.152465] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware.bin failed with error -2  [   10.152467] ath10k_pci 0000:03:00.0: could not fetch firmware (-2)  [   10.152470] ath10k_pci 0000:03:00.0: could not fetch firmware files (-2)  [   10.152472] ath10k_pci 0000:03:00.0: could not probe fw (-2)

After Installing Ubuntu 16.04 in Acer laptop with Qualcom Atheros , it does not work. I tried ,   sudo rfkill list all 0: hci0: Bluetooth     Soft blocked: no     Hard blocked: no 1: acer-wireless: Wireless LAN     Soft blocked: no     Hard blocked: no   Then , checked  uname -r 4.4.0-21-generic   and , as suggested I tried ,   lspci -nnk | grep -iA2 net; dmesg | grep ath10k 02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 15)     Subsystem: Acer Incorporated [ALI] RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [1025:0987]     Kernel driver in use: r8169     Kernel modules: r8169 03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:0042] (rev 30)     Subsystem: Foxconn International, Inc. Device [105b:e09a]     Kernel driver in use: ath10k_pci [    7.100283] ath10k_pci 0000:03:00.0: pci irq msi interrupts 1 irq_mode 0 reset_mode 0 [    7.390307] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/cal-pci-0000:03:00.0.bin failed with error -2 [    7.390332] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-5.bin failed with error -2 [    7.390336] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-5.bin': -2 [    7.390350] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-4.bin failed with error -2 [    7.390353] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-4.bin': -2 [    7.390365] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-3.bin failed with error -2 [    7.390369] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-3.bin': -2 [    7.390381] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-2.bin failed with error -2 [    7.390384] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-2.bin': -2 [    7.390396] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware.bin failed with error -2 [    7.390398] ath10k_pci 0000:03:00.0: could not fetch firmware (-2) [    7.390401] ath10k_pci 0000:03:00.0: could not fetch firmware files (-2) [    7.390404] ath10k_pci 0000:03:00.0: could not probe fw (-2)   Now what should I do ??


I recently found out it is inappropriate to  (I asked before doing it). After that, another question came to mind:  Since Stack Overflow seems to have a bigger community and you can ask questions on all sorts of topics related to technology (especially systems and programming), isn't it just better to stick to that one QA Site than spread your involvement with the other great QA Sites that Stack Exchange offers?  PS: I am new to the community, and this is a legitimate question.

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


Such as:  http://tech.e freedom.com/Question/1-2837475/Jetty-offline-documentation

of Stack Overflow, all content posted on Stack Exchange sites by their users (i.e. you wonderful people) has been provided to the whole universe under . For my fellow non-lawyers, that license basically means:   Anyone can use any Stack Exchange posts at any time without having to ask for permission Making money off of the copied content is permitted You don't even have to copy stuff from here verbatim; you can just use it as a starting point and make whatever edits you want There are just two rules you have to follow:   You have to provide . Simple links to the original post and author info are just fine. You have to  and allow other people to use your content, as long as they follow these very same rules. How meta!    (If you ever forget any of that, and want to refresh your memory, the license info is linked to in the footer of every page.)  There are, in fact, a lot of people who republish varying amounts of our content for assorted reasons. Unfortunately, there are some Stack Content Republishers Attributing Poorly and/or Excelling at Ranking (SCRAPERs, for short).  In this context, "attributing poorly" means any use that doesn't follow our attribution rules or make any other reasonable attempt at give credit. This can get pretty egregious; I've seen SCRAPERs that not only don't link back to SE originals, but also use fake author info and post dates to make it harder to find originals. By "excelling at ranking," I'm referring to copycat sites that end up higher in Google results than the original SE sites do for the same content. That's not necessarily wrong, but in some cases, it indicates inappropriate SEO hackery.  So, the question is: what can you do if you spot a SCRAPER?


I am doing SEO of an domain, the domain is 16 years old and used by same person for multiple businesses in the past. Currently it is using for a business from last 5 years. The company is in the field of Training and certification for IT professionals. The businesses attached with the domain in the past will affect the current SEO project?

I want to purchase a few expired domains, who have some backlinks, but some of those sites have PR of -1 with backlinks which are pretty bad.  But what exactly do I need to look for when looking for an expired domain (and I don't want to pay up the nose for a PR3+ domain).


I tried to convert html to plain text with the following function but still getting error while converting.   private static string HtmlToPlainText(string html)         {             const string tagWhiteSpace = @"(>|$)(\W|\n|\r)+<";//matches one or more (white space or line breaks) between '>' and '<'             const string stripFormatting = @"<[^>]*(>|$)";//match any character between '<' and '>', even when end tag is missing             const string lineBreak = @"<(br|BR)\s{0,1}\/{0,1}>";//matches:
,
,
,
,
,
             var lineBreakRegex = new Regex(lineBreak, RegexOptions.Multiline);             var stripFormattingRegex = new Regex(stripFormatting, RegexOptions.Multiline);             var tagWhiteSpaceRegex = new Regex(tagWhiteSpace, RegexOptions.Multiline);              var text = html;             //Decode html specific characters             text = System.Net.WebUtility.HtmlDecode(text);             //Remove tag whitespace/line breaks             text = tagWhiteSpaceRegex.Replace(text, "><");             //Replace
 with line breaks             text = lineBreakRegex.Replace(text, Environment.NewLine);             //Strip formatting             text = stripFormattingRegex.Replace(text, string.Empty);             text = text.Replace(">", "");              return text;         }   when I tried to debug the code it display \r and \r\n also in plain text output.This function is not properly convert the html to plain text. Can anyone suggest me any other conversion function?  Thanks

I have snippets of Html stored in a table. Not entire pages, no  tags or the like, just basic formatting.  I would like to be able to display that Html as text only, no formatting, on a given page (actually just the first 30 - 50 characters but that's the easy bit).  How do I place the "text" within that Html into a string as straight text?  So this piece of code.  Hello World.

Is there anyone out there?
   Becomes:  Hello World. Is there anyone out there?


Let $Y_1,Y_2,\ldots,Y_n$ be independently distributed random variables such that $Y_i\sim\mathcal N(\alpha+\beta x_i,\sigma^2)$ for all $i=1,\ldots,n$. If $\hat\alpha$ and $\hat\beta$ be the least square estimates of $\alpha$ and $\beta$ respectively, then what is the joint distribution of $(\hat\alpha,\hat\beta)$?  We consider the model $y=\alpha+\beta x+\epsilon$ where $y$ is stochastic and $x$ is non-stochastic. We have the paired observations $(x_i,y_i)$ and we assume that the errors $\epsilon_i\stackrel{\text{i.i.d}}{\sim}\mathcal{N}(0,\sigma^2)$ for all $i$. Define $s_{xx}=\sum (x_i-\bar x)^2,\,s_{yy}=\sum(y_i-\bar y)^2$ and $s_{xy}=\sum(x_i-\bar x)(y_i-\bar y)$. From the normal equations we have $\hat\alpha=\bar y-\hat\beta\bar x$ and $\hat\beta=\dfrac{s_{xy}}{s_{xx}}$. Transforming $\mathbf Y=(Y_1,\ldots,Y_n)\to(Z_1,\ldots,Z_n)=\mathbf Z$ such that $\mathbf Y=\mathbf{A\,Z}$ where $\mathbf A$ is an orthogonal matrix with its first two rows $\left(\frac{1}{\sqrt n},\ldots,\frac{1}{\sqrt n}\right)$ and $\left(\frac{x_1-\bar x}{\sqrt{s_{xx}}},\ldots,\frac{x_n-\bar x}{\sqrt{s_{xx}}}\right)$. From the distribution of the $Z_i$'s, one can show that $\bar y\sim\mathcal N\left(\alpha+\beta\bar x,\frac{\sigma^2}{n}\right)$ and $\hat\beta\sim\mathcal N\left(\beta,\frac{\sigma^2}{s_{xx}}\right)$, both independently distributed of each other. From this, one gets $\hat\alpha\sim\mathcal{N}\left(\alpha,\sigma^2\left(\frac{1}{n}+\frac{\bar x^2}{s_{xx}}\right)\right)$. So we have the two least square estimates each having a univariate normal distribution. They are definitely not independent; I have found they have correlation $\text{Corr}(\hat\alpha,\hat\beta)=-\frac{\sqrt{n}\bar x}{\sqrt{\sum x_i^2}}$. But how can I find the joint distribution of $(\hat\alpha,\hat\beta)$ from this? I cannot simply conclude that they are jointly normal. They are probably jointly normal but how does it follow? The following related posts came up during a search, but don't quite get the answer I am looking for:         Edit. The joint distribution of $(\hat\alpha,\hat\beta)=(\bar y-\hat\beta\bar x,\hat\beta)$ is bivariate normal simply because $\bar y$ and $\hat\beta$ are independent normal variables (details ). This follows from the property that different linear combinations of independent normal variables (and hence jointly normal variables) are themselves jointly normal.

I previously learned about sampling distributions that gave results which were for the estimator, in terms of the unknown parameter. For example, for the sampling distributions of $\hat\beta_0$ and $\hat\beta_1$ in the linear regression model $Y_i = \beta_o + \beta_1 X_i + \varepsilon_i$  $$ \hat{\beta}_0 \sim \mathcal N \left(\beta_0,~\sigma^2\left(\frac{1}{n}+\frac{\bar{x}^2}{S_{xx}}\right)\right) $$ and $$ \hat{\beta}_1 \sim \mathcal N \left(\beta_1,~\frac{\sigma^2}{S_{xx}}\right) $$  where $S_{xx} = \sum_{i=1}^n (x_i^2) -n \bar{x}^2$  But now I have seen the following in a :     Suppose we fit the model by least squares in the usual way. Consider   the Bayesian posterior distribution, and choose priors so that this is   equivalent to the usual frequentist sampling distribution, that   is......      $$ \left( \begin{matrix} \beta_0  \\ \beta_1  \end{matrix} \right)  \sim \mathcal  N_2\left[\left(\begin{matrix} \hat{\beta}_1  \\  \hat{\beta}_2  \end{matrix} \right),~\hat{\sigma}^2  \left(\begin{matrix}   n & \sum_{i=1}^{n}x_i \\   \sum_{i=1}^{n}x_i &  \sum_{i=1}^{n}x_i^2  \end{matrix}  \right) ^{-1}\right] $$   This is confusing me because:     Why do the estimates appear on the left hand side (lhs) of the first 2 expressions, and the right hand side (rhs) of the last expression? Why do the beta hats in the last expression have 1 and 2 subscripts instead of 0 and 1? Are these just different representations of the same thing? If they are, could someone show my how they are equivalent? If not, could someone explain the difference? Is it the case that the last expression is the "inversion" of the first two? Is that why the 2x2 matrix in the last expression is inverted and estimates/parameters are switched from rhs$\leftrightarrow$lhs? If so could someone show me how to get from one to the others?


$$\sum_{n=2}^\infty\frac{(-1)^n}{\sqrt[3]{n}+ (-1)^{\frac{n(n+1)}{2}}}$$ None of convergence tests I know (Leibnitz, Dirichlet, Abel) works becaues of the denominator.  I know that sum of convergent series is convergent too and I tried using this information with no results.

Let $$\displaystyle a_n=\sum_{n=2}^{\infty} \frac{(-1)^n}{n^{\frac{1}{3}}+(-1)^{\frac{n(n+1)}{2}}}$$   so I divide it into four series $4k, 4k+1, 4k+2, 4k+3$ and I pair for instance $4k, 4k+1$ and $4k+2, 4k+3$ and prove that these two series is convergent and conclude that since  both series are convergent so the sum of it is also convergent but I'm not sure if it's legall   second series I'm not sure is like this $\displaystyle b_n=\frac{1}{1}+\frac{1}{3}-\frac{1}{2}+\frac{1}{5}+\frac{1}{7}-\frac{1}{4}+\frac{1}{9}+\frac{1}{11}-\frac{1}{6}+...$   here I also split it into smaller parts namely $\displaystyle \sum_{n=1}^{\infty}\frac{1}{4n-3}+\sum_{n=1}^{\infty}\frac{1}{4n-1}-\sum_{n=1}^{\infty}\frac{1}{2n}$ and I prove that $\displaystyle \frac{1}{4n-3}+\frac{1}{4n-1}-\frac{1}{2n}<\frac{1}{n^2} \cdot c $ for some const c so it implies that origin series is convergent or not ?


Why is  $$(n+1)(n+2) \cdots (n+s), \text{ with } n,s \in ℕ$$  divisible by $s!$ ?  I derived this from the formula that gives the number of combinations of class $k$ with $n$ elements:  $$\frac{n!}{k!(n-k)!}$$

How can we prove that the product of $n$ consecutive integers is divisible by $n$ factorial?     Note: In this  and the comments here the OP has clarified that he seeks a proof that "does not use the properties of binomial coefficients". Please post answers in said newer thread so that this incorrectly-posed question may be closed as a duplicate.


I am a selenium C# developer, and have just recently conducted an interview with a company. During this process I was asked a lot of questions about "hypothetical" framework questions, and how I would architect a system of tests for a product. Towards the end of the interview I was asked if I could showcase a framework that I have implemented in the past, and of course with non-disclosure agreements I am unable to share that information. The interviewer seemed disappointed that I didn't have one created that he could look at, and I feel as though the interview went downhill from there. I have decided to create my own framework so that I can show potential employers my work. The question that I have is:      What is a website that I can test(create the framework around), that is not my employers?   I am just wondering what sites other professionals in this field have used for there own personal frameworks.

I want to learn Selenium, but I don't know what to code. Sure, I can throw Google some queries, I can fill out some forms, press buttons, find divs and links, etc. But I think this stuff is pretty basic.  What would be more "advanced" ideas to try out? Can you give real-life examples?


I am having difficulty understanding $\sqrt -i$ from other sources (such as Wolfram Alpha) I have found it to equal $-(-1)^\frac{3}{4}$ but do not understand the steps in to reach this conclusion. I know it may be trivial but any assistance would be greatly appreciated.

Can you enter the rabbit hole recursively?  If the $ \sqrt{-1} = i $ then, what does $ \sqrt{-i} $ equal?


He everyone, today see some code from a web, and i don't know how is function (a) call to function zero(), one()... ? Why this can happen ? function zero(func)   { return func ? func(0) : 0; }; function one(func)    { return func ? func(1) : 1; }; function two(func)    { return func ? func(2) : 2; }; function three(func)  { return func ? func(3) : 3; }; function four(func)   { return func ? func(4) : 4; }; function five(func)   { return func ? func(5) : 5; }; function six(func)    { return func ? func(6) : 6; }; function seven(func)  { return func ? func(7) : 7; }; function eight(func)  { return func ? func(8) : 8; }; function nine(func)   { return func ? func(9) : 9; };  function plus( b )      { return function( a ) { return a + b; }; }; function minus( b )     { return function( a ) { return a - b; }; }; function times( b )     { return function( a ) { return a * b; }; }; function dividedBy( b ) { return function( a ) { return a / b; }; };  // seven(times(five())) => 12

I've seen references to curried functions in several articles and blogs but I can't find a good explanation (or at least one that makes sense!)


I seem to have an anomalous drop in rep.  2656 points gone in the past hour.  I know that the ways of SO are fleet and mysterious, but I would really like to know what triggers this, if not a bug.    Since I also see that my username was changed (from NewAlexandria), I presume this is probably a bug.   Any insight is appreciated.  I've left my contact info in the shot in case anyone needs to contact me directly about the tech details.  I also seem to have lost all my badges - so I'm thinking bug, or I garnered some kind of extreme ban-punishment.  This is the only SO profile affected.  Note: I've received some upvotes, and my rep didn't correct.

This user is only displaying 56 rep.   But surely (s)he has much more than that.        The user has also never given out any bounties.  Also, badges are missing:


Let $a_n$ be a sequence, such that $-5$ and $5$ are two partial limits of the sequence. In addition, for all $n$, $|a_{n+1}-a_n|<\frac{1}{n}$. Prove that $0$ is a partial limit of the sequence $a_n$.  The question is a bit unclear. The statement in the absolute value above suggests using Cauchy Sequences, but I don't know if and how to do it. $a_n$ does not converge since it has more than one partial limit. How can use it? Thanks!

Looking for guidance for the following question: Let $a_n$ a sequence, such that $\left| {{a_{n + 1}} - {a_n}} \right| < \frac{1}{n}$ and $\{5,-5\}$ are partial limits of $a_n$. Show that $0$ is also a partial limit.    I don't see how both conditions can live together. Obviously, the difference between the terms of $a_n$ are getting closer and closer, so how can this sequence have $\{5,-5\}$ as partial limits?     I'd be glad for clarification and guidance :)


Is the comma before "respectively" needed when "respectively" is the last word in a sentence?  Garry, Michael and John scored 10, 26 and 18 points, respectively.

In the graph for all arrests, and DUI arrests, the effect of the MLDA is about 125 and 50 increase in arrests rate respectively.    I personally think no comma should be put before the word respectively. And what about the comma before the phrase and DUI arrests? Should I remove it? I want to say there is one graph for each and make that clear.  So maybe I should change the first part of the sentence to something like: .     In both graphs for all arrests and DUI arrests, the effect of the MLDA is about a 125 and 50 increase in arrests rate respectively.


Do there exist sequences $\{a_n\}$ and $\{b_n\}$ satisfying all of the following properties?   $a_n>0$ and $b_n>0$ $\{a_n\}$ and $\{b_n\}$ are both decreasing $\sum a_n$ and $\sum b_n$ both diverge $\sum\min\{a_n,b_n\}$ converges

Find examples of two series $\sum a_n$ and $\sum b_n$ both of which diverge but for which $\sum \min(a_n, b_n)$ converges. To make it more challenging, produce examples where $a_n$ and $b_n$ are positive and decreasing.  Edit: This problem is taken verbatim from Exercise 2.7.11 on page 68 of Abbott's Understanding analysis.


I play ME3 on xbox and a friend has it on PC. I know we can't game together between platforms but I was wondering if I bought ME3 on the PC is there any way that I can use the same profile that I use with xbox so I have the same classes and weapons unlocked without having to start over again? I'm thinking not but I thought it worth checking...

Since it's , is it possible to convert a savegame from one platform (PC, XBox, PS3) to another platform?  By doing so, this might allow to switch from one platform to another to enable playing with a friend (supposing you have two retail copy on the same platform).


I have lots of schemas and tables. I want to generate create script of all of my tables. I am using below statement and it is working pretty well.  SELECT DBMS_METADATA.GET_DDL('TABLE','table_name','schema') FROM DUAL   But because this statement also generates all primary and foreign key scripts that belong to table when I try to insert my tables to another location I am getting "ORA-00942: table or view does not exist" error because I didn't create key's reference tables yet.  You can say that, previousl  So, is there any way to not include primary and foreign keys in create table scripts

I have lots of schemas and tables. I want to generate create script of all of my tables. I am using below statement and it is working pretty well.  SELECT DBMS_METADATA.GET_DDL('TABLE','table_name','schema') FROM DUAL   But this statement also generates all primary and foreign key scripts that belong to table. So, is there any way to not include primary and foreign keys in create table scripts


My database contains fields with special characters. How can I read these characters? With the next code, Ma?? (Maçã) is returned. Do I have this code:       $nome=$_POST['nome'];  $sql=mysqli_query($con, "SELECT idalimento, nome_pt FROM alimento WHERE  nome_en= '$nome'");  while($exibe = mysqli_fetch_assoc($sql)){ echo $exibe["nome_pt"]."<br>"; } ?>   Can someone help me? Thanks

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


Cards the say target player, but say nothing about Planeswalkers such as those printed before Planeswalkers were a thing. Can i target a planeswalker in place of a player?

Many older cards refer to players or opponents, e.g. "deal 3 damage to target player". Can any of these be used on planeswalkers, beyond the fact that you can simply attack them with creatures?  For example:   Would my opponent discard a card if  damaged a planeswalker they control? Would my opponent, the planeswalker, neither, or both amass poison counters from an unblocked ? Can  target a planeswalker? Does  affect planeswalkers? Can  prevent damage to a Planeswalker? Would  be obligated to take damage being dealt to a planeswalker? Can a planeswalker gain loyalty from ? Can  prevent damage to a planeswalker?


In fact I just want to change the web directory to another folder in Ubuntu, but  403 forbidden error give a mass to me.  I have tried a lot of ways on google to solve this problem, but those solutions can not solve my problem, such as change the permission of the folder,  This is /etc/apache2/sites-enabled/000-default.conf file (see comments on lines with ##############):  <VirtualHost *:80>  # The ServerName directive sets the request scheme, hostname and port that # the server uses to identify itself. This is used when creating # redirection URLs. In the context of virtual hosts, the ServerName # specifies what hostname must appear in the request's Host: header to # match this virtual host. For the default virtual host (this file) this # value is not decisive as it is used as a last resort host regardless. # However, you must set it for any further virtual host explicitly. #ServerName www.example.com  ServerAdmin webmaster@localhost DocumentRoot /usr/www  ############## (if I change to /var/www no forbidden)  # Available loglevels: trace8, ..., trace1, debug, info, notice, warn, # error, crit, alert, emerg. # It is also possible to configure the loglevel for particular # modules, e.g. #LogLevel info ssl:warn  ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined  # For most configuration files from conf-available/, which are # enabled or disabled at a global level, it is possible to # include a line for only one particular virtual host. For example the # following line enables the CGI configuration for this host only # after it has been globally disabled with "a2disconf". #Include conf-available/serve-cgi-bin.conf </VirtualHost>  # vim: syntax=apache ts=4 sw=4 sts=4 sr noet   and this is /etc/apache2/apache2.conf file  <Directory /usr/www/> ############## (if I change this to /var/www/ no problem.) Options Indexes FollowSymLinks AllowOverride None Require all granted </Directory>   who can help me?

I have installed Apache(LAMP) web server on my ubuntu machine and I want to do the above mentioned thing.I have tried creating symbolic links in the /var/www directory but it only shows files but not directories inside the directory linked.I want to redirect /var/www to my home folder so that I can access all the files and directories contained therein.Please help me.


When I run sudo apt-get update I get this error:  W: Failed to fetch http://repo.mysql.com/apt/ubuntu/dists/trusty/InRelease  Unable to find expected entry 'utilities-1.4/binary-amd64/Packages' in Release file (Wrong sources.list entry or malformed file)  E: Some index files failed to download. They have been ignored, or old ones used instead.   What can I do?

I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.


We know the following theorem about UFD.  Theorem.  Let $R$ be a factorization domain. Then, $R$ is a UFD iff every irreducible element is prime.  The forward part is okay, i.e., if $R$ is a UFD, then every irreducible is prime.  Now, my question is if we modify the statement a bit, then does the converse part remain true?  Statement.  Let $R$ be an integral domain. Then, $R$ is a UFD only if every irreducible element is prime.  The above statement is no true. We are not giving the guarantee that factorization exists, but we are asking can still every irreducible be prime? I am asking this because we need to use the existence of factorization in the converse part of the theorem I mentioned.  I had searched the site   and found counterexamples there but nobody mentions how such examples can be constructed.  So,I am looking for a general method to construct such rings.

In the integral domain every prime is irreducible. But the converse is not true, for example, $1+\sqrt{-3}$ is an irreducible but not a prime in ${\Bbb Z}[\sqrt{-3}]$. In a UFD, "prime" and "irreducible" are equivalent.   Here is my question:     Is there a non-UFD integral domain such that prime is equivalent to irreducible?