How can a ratio containing only real numbers have a complex value?

Solving this equation  $$x = 1-\cfrac{2}{1-\cfrac{2}{1-\cfrac{2}{\ddots}}}$$  Sub in $x$  $$x=1-\frac{2}{x}\implies x^2=x-2 \implies x^2-x=-2$$  Solve through completing the square \begin{align} x^2-x+\frac{1}{4}&=-2+\frac{1}{4}\\ \left(x-\frac{1}{2}\right)^2&=-\frac74\\ x-\frac{1}{2}&=\pm\sqrt{\frac{7}{4}}i\\ x&=\frac{1}{2}\pm\sqrt{\frac{7}{4}}i\\ \end{align} When you substitute this value back in for $x$ it works.  But i don't understand why a equation like this can equal a complex value  Maybe I am missing something important here?  EDIT: So this equation diverges right. Does that make my working invalid, or just explain the non-real part.  Can anything useful be done by defining this recursively  $$f(x)=1-\frac{2}{f(x)}$$  and then using a seed value  I also wonder whether we would end up dividing by zero at some point. Can you prove we do or don't?


why are unanswered questions not sorted by date?

I am looking to get some rep by answering unanswered questions. I only have time to answer a few at a time. I take a look at the unanswered list and post some good answers (i think) and afterwards I see that the question was posted over a year ago. The odds of that person coming back to that question after such a long time is not good. Besides that, they probably found their answer somewhere else.  So why do these really old questions show up on the first page of the unanswered list? The person that asked that question already thinks the site sucks cause they didn't get help with their question. Why should a newer unanswered question get burried? Do you want people not to find the new question so it yields the same fate?  feature-request: sort unanswered questions by date desc


Maximal ideal among those that are not finitely generated

Let $R$ be a commutative ring. We consider the set of ideals which are not finitely generated: $$ \Theta :=\{I ~:~ I\textrm{ is an ideal of } R\textrm{ which is not finitely generated} \}. $$ We assume that $\Theta \neq \varnothing$. By Zorn's lemma, let $I$ be a maximal element of  $\Theta$.  Show that $I$ is a maximal ideal of $R$.


In recent months, my electricity bill has been steadily going up, from 20% to 40% to, now, 100%. It's doubled.  I don't see any appliance running continuously except several ceiling fans. All my appliances are regular, meaning what one would find at home, such as fridges, cooktop, water heater, oven, lights, etc. There is a pool pump I turn on and off daily.  Where should I start to tackle the problem? I have divided this problem into two categories: house appliance problem and meter problem. I'd like to see if this is appliance problem first and deal with the meter separately. The meter is read monthly on the 20th. So, the bill jump is real, not estimated.


Proving inequalities hold for all values

Show that the inequality  $$\frac st + \frac tr + \frac rs \ge 3$$  holds for all positive $r,s$ and $t$.


What happens with Whatsapp iCloud backup if I don't restore media

I just dropped my iPhone XS Max in the water the other day and now it is in the shop for repair. I have a fairly large Whatsapp backup in the iCloud of 18GB. I currently have a replacement phone for the time being. I just restored just the chats to this temp phone but I can't restore the media on it since it doesn't have enough storage space. I now have the option to skip the media restore. My question is, I don't mind not having my media on this temp phone, as long as I can restore all my media received in the meantime on my main phone when it comes back from repair. If I skip the media restore now, will this also delete the media on the iCloud backup if I do a backup of my temp phone?


How to discourage 'mean' punishment of answers?

In most fora, there seems to be a reasonably kind and tolerant atmosphere, but I have seen several times on Stack Overflow, that people appear to almost 'gang up' to punish answers, for reasons that very often seem very petty - like here:    where a user, 'Rishabh Jhalani', has given an essentially correct answer, but is voted down for a very minor thing. I have experienced this myself, and while it doesn't cause me sleepless nights, it does tend to discourage me from engaging with the community. After all, I made an effort, however small, to contribute something - for free - in good faith.   I would like to see a reduction in this sort of behaviour, so I suppose there are two questions: Should we try to discourage this sort of small-mindedness? And, if so, how? I can imagine a scheme, where you can't down-vote, unless you also provide a comment, or a scheme, where a user's total up- and down-votes are tallied and visible to the community. What do people think?


Is the tabbed content in product page hurting SEO?

Is tabbed content in product page bad for SEO? If so, how should I make it more SEO friendly?


redefining \label and \ref when using hyperref

I'm editing a book that includes about 25 papers written in LaTeX by different authors.  Since many of them use the same \label, to avoid collisions I redefined the \label command (and \ref and \pageref and \cite and \bibitem)  so that if the third paper has  \label{main_theorem} the aux file actually uses the tag "iii:main_theorem", and \ref{main_theorem} actually refers to the same tag.  I did a similar thing for \cite and \bibitem.  %*************** bib/cite hacks \let\TheReal@citex=\@citex \let\TheReal@bibitem=\@bibitem \let\TheReal@lbibitem=\@lbibitem \gdef\@lbibitem[#1]#2{\TheReal@lbibitem[{#1}]{#2\roman{chapter}}} \gdef\@bibitem#1{\TheReal@bibitem{#1\roman{chapter}}} \gdef\@citex[#1]#2{% \toks@={}\count@=0% \@for\@citec:=#2\do{% \advance\count@ 1 \ifnum\count@=1\edef\0{\the\toks@\expandafter\expandafter\noexpand\@citec\roman{chapter}}% \else\edef\0{\the\toks@,\expandafter\expandafter\noexpand\@citec\roman{chapter}} \fi% \toks@=\expandafter{\0}}% \TheReal@citex[#1]{\the\toks@}% } %************** label/ref/pageref hacks  %%%%%%%%%%%%% must be before ams pkgs \let\TheRealLabel=\label \let\TheRealRef=\ref \let\TheRealPageref=\pageref \gdef\label#1{\TheRealLabel{\roman{chapter}:#1}} \gdef\ref#1{\TheRealRef{\roman{chapter}:#1}} \gdef\pageref#1{\TheRealPageref{\roman{chapter}:#1}}   This all worked fine until I used hyperref, which seems to ignore the redefinition of \label, whether I load it before or after the above code.  Any suggestions?  It would be nice if the redefinition would work whether or not hyperref was loaded, so I don't want to just grab the defintion of \label out of the package and tweak it.  I'm also open to alternative methods.  Redefining \label and \ref just seemed the most straightforward (to me) solution.  Note that I also want to be able to refer to the inner labels from outside, as well.  For example, I might want to say "the main theorem of the third paper is  \ChapRef{iii}{main_theorem}  from within the introduction (a different chapter).


Running df -h gives me the following:  Filesystem                       Size  Used Avail Use% Mounted on /dev/mapper/centos-root           50G   49G  1.3G  98% / devtmpfs                         7.8G     0  7.8G   0% /dev tmpfs                            7.8G     0  7.8G   0% /dev/shm tmpfs                            7.8G  769M  7.1G  10% /run tmpfs                            7.8G     0  7.8G   0% /sys/fs/cgroup /dev/mapper/centos-home           78G  182M   78G   1% /home /dev/sda1                        497M  338M  160M  68% /boot tmpfs                            1.6G     0  1.6G   0% /run/user/0   I want to allocate more spare to /dev/mapper/centos-root, by reducing the allocation for /dev/mapper/centos-home  How would I remove 50GB from home and give it to root?    Further Info  Running mount tells me the following:  /dev/mapper/centos-home on /home type xfs (rw,relatime,seclabel,attr2,inode64,noquota)   Does this mean it's the XFS filesystem? When I run resize2fs I get the following error:  resize2fs: Bad magic number in super-block while trying to open /dev/centos/home Couldn't find valid filesystem superblock.


Execution time for adding element in LinkedList vs ArrayList

class ExeTime { public static void main (String[] args) {      LinkedList<Integer> ll = new LinkedList<Integer>();     ArrayList<Integer> al = new ArrayList<Integer>();      addElement("LinkedList", ll);     addElement("ArrayList", al); }  static void addElement(String type, List listType){     final long startTime = System.currentTimeMillis();      for(int i = 0; i<= 1E5; i++){         listType.add(i);     }     final long endTime = System.currentTimeMillis();     final long timeTaken = endTime - startTime;     System.out.println("Type:::: "+type+" ::timeTaken:: "+timeTaken); }  }   Output for above piece of code is ::::  Type:::: LinkedList ::timeTaken:: 11  Type:::: ArrayList ::timeTaken:: 18  Now if I interchange the call for addElement method then I get the following output::::  Type:::: ArrayList ::timeTaken:: 10  Type:::: LinkedList ::timeTaken:: 16  I fail to understand why the sequence to add integer to a LinkedList and ArrayList change the execution time of the method. I tried the same for removing the elements and the results were OK. Could anyone please help me get to know as why this might be happening only while adding elements...


This is a question from the free Harvard online abstract algebra .  I'm posting my solutions here to get some feedback on them.  For a fuller explanation, see  post. This problem is from assignment 5.  a) Prove that the relation $x$ conjugate to $y$ in a group $G$ is an equivalence relation on $G$. b) Describe the elements $a$ whose conjugacy class (= equivalence class) consists of the element $a$ alone.  a) Let $G$ be a group and $R$ be a relation on $G$ defined by $a\sim b$ if $a$ is conjugate to $b$.  Then $a\sim b$ if there is a $g\in G$ such that $a = gbg^{-1}$.  Let $a$ be an element of $G$.  Then $a=eae^{-1}$.  So $a\sim a$ and $R$ is reflexive.  Let $a$ and $b$ be elements of $G$ such that $a\sim b$.  Then there is a $g\in G$ such that $a=gbg^{-1}$.  Then $b=g^{-1}ag$.  Since $g^{-1}\in G$, $b\sim a$.  Hence, $R$ is symmetric.  Let $a,b$, and $c$ be elements of $G$ such that $a\sim b$ and $b\sim c$. Then there are elements $g,g^\prime\in G$ such that $a=gbg^{-1}$ and $b=g^\prime cg^{\prime -1}$.  Then $a=g(g^\prime c g^{\prime -1})g^{-1}=(gg^\prime)c(g^{\prime -1}g^{-1})=(gg^\prime)c(gg^\prime)^{-1}$. Since $gg^\prime\in G$, $a\sim c$.  Hence $R$ is transitive.  Therefore $R$ is an equivalence relation on $G$. b) Let $S$ be the set of elements of $G$ such that, for $s\in S$, $s=gsg^{-1}$ for any $g\in G$.  Then $sg=gs$.  So $S$ is the set of elements that commute with every element of $G$.  In other words, $S$ is the center of $G$. Again, I welcome any critique of my reasoning and/or my style as well as alternative solutions to the problem. Thanks.


reduce whitespace between header and content in scrlttr2

I am using scrlttr2 and want to reduce the amount of whitespace between the header and the content of the letter (see picture)    Here is the corresponding code:  \documentclass[fontsize=12pt,    paper=a4,    enlargefirstpage=on,    pagenumber=headright,    headsepline=off,    parskip=half,         fromphone=on,    fromrule=off,    fromfax=off,    fromemail=on,    fromurl=off,    fromlogo=off,    addrfield=on,    backaddress=off,    subject=beforeopening,    locfield=narrow,    foldmarks=off,    numericaldate=off,    refline=narrow]{scrlttr2} %--------------------------------------------------------------------------- \usepackage[T1]{fontenc} \usepackage[latin1]{inputenc} \usepackage[utf8]{inputenc} %--------------------------------------------------------------------------- \usepackage{lmodern} \usepackage{color} \usepackage{marvosym}  \usepackage{ifthen}  \definecolor{firstnamecolor}{rgb}{0.65,0.65,0.65} \definecolor{familynamecolor}{rgb}{0.45,0.45,0.45} \definecolor{footersymbolcolor}{rgb}{0.20,0.40,0.65} \definecolor{addresscolor}{rgb}{0.35,0.35,0.35} %grau  \newcommand*{\addressfont}{\small\sffamily\mdseries\slshape} \newcommand{\footersymbol}{~~\color{footersymbolcolor}\normalfont\textbullet\color{addresscolor}\addressfont~~~} %--------------------------------------------------------------------------- \setkomafont{fromname}{\sffamily \LARGE} \setkomafont{fromaddress}{\sffamily}%%    Instead of \small \setkomafont{pagenumber}{\sffamily} \setkomafont{subject}{\mdseries} \setkomafont{backaddress}{\mdseries} \usepackage{mathptmx} %--------------------------------------------------------------------------- \begin{document} %--------------------------------------------------------------------------- \LoadLetterOption{KOMAold}  \makeatletter \@setplength{sigbeforevskip}{50pt}  \@setplength{firstfootvpos}{300mm} page \@setplength{firstheadvpos}{10mm} \@setplength{firstheadwidth}{\paperwidth} \ifdim \useplength{toaddrhpos}>\z@   \@addtoplength[-2]{firstheadwidth}{\useplength{toaddrhpos}} \else   \@addtoplength[2]{firstheadwidth}{\useplength{toaddrhpos}} \fi \@setplength{foldmarkhpos}{6.5mm} %\@setplength{refvpos}{\useplength{toaddrvpos}} \makeatother %--------------------------------------------------------------------------- % Sender information \newcommand{\myFirstname}{John} \newcommand{\myFamilyname}{Odd} \newcommand{\myStreet}{Street} \newcommand{\myTown}{NY} \newcommand{\myZipcode}{11233} \newcommand{\myPhone}{+123 456 4879} \newcommand{\myMail}{john@internet.com} \setkomavar{signature}{\myFirstname\ \myFamilyname} %--------------------------------------------------------------------------- \firsthead{   \begin{flushright}     \renewcommand{\baselinestretch}{0.8}     \sffamily\mdseries\Large\color{firstnamecolor}\myFirstname\ \color{familynamecolor}\myFamilyname\\     \parbox{\textwidth}{\color{footersymbolcolor}\rule{\textwidth}{2pt}}     \normalfont\small\color{black} \myStreet \\ \myZipcode, \myTown \\ \myMail \\\myPhone   \end{flushright} } %--------------------------------------------------------------------------- \setkomavar{place}{\myTown} \setkomavar{date}{\today} %---------------------------------------------------------------------------  \setkomavar{enclseparator}{: } %---------------------------------------------------------------------------  \pagestyle{myheadings}%% No header  \begin{letter}{International Company Coorporation\\ Mrs. Jane Doe\\ Some street 11 \\ SF, 54321} %--------------------------------------------------------------------------- % Further options \KOMAoptions{} %--------------------------------------------------------------------------- \setkomavar{subject}{subject} %--------------------------------------------------------------------------- \opening{Dear,} text  \closing{KR} \encl{enclosed} \end{letter} \end{document}   I am thankful for any hints.


How to write jUnit tests for random output?

Testing code that has a predefined input and output parameters is relatively easy when compared to writing tests for code that has a portion of randomness, as we must check if the random generator is biased or not.  An example of a library that uses random numbers is java.util.Collections.shuffle(List<?> list) which shuffles a collection of objects, following the .  How to write jUnit tests for code that has random output? Not only for the shuffle, but testing randomness in general.


Weakly continuous operators are continuous

I'm trying to understand  on MSE.  Let $X$ and $Y$ be Banach spaces, and let $T:X\rightarrow Y$ be a linear map such that $f\circ T$ is continuous for all $f\in Y'$.  Show that $T$ is continuous.  Jonas provides a good simple start of the problem but I was not able to physically show the contradiction. I have found a similar problem  which they took a completely different route and user38355 didn't clearly give proof of the direction I'm trying to understand.


Started with an algorithms problem which says item is sold in 3 different sizes of boxes. These 3 boxes have 6, 9, 20 items each. Input is n, figure out if you can buy exactly n items.   It got me thinking that there is a number m, if n >= m then you always can buy n items. If you generalize number of items in a box into s1 s2 s3 ... sy, number of boxes to buy into k1 k2 k3 ... ky, number of items you want to buy into n.  k1*s1 + k2*s2 + ... + ky*sy = n  How do I find the value m, if n >= m there's always gonna be k1, k2, ..., ky which satisfies above equation. So that the algorithm can say yes you can without doing anything if n is large enough.


No internet after 16.04 LTS 18.04.01 upgrade

This may seem like a duplicate, but many solutions have been unsuccessfully tried. Currently I have no internet, WIFI or Ethernet. Sometimes: "no wifi adapter found".  The device is HP dm4, dual boot with Windows 7.    Here is the  The issue started 3 weeks ago as no GUI after 16.04 LTS to 18.04.01 upgrade.  At that time, I was able to use the terminal to connect to the Internet and run "fixes" in   Then mysteriously, the GUI ran after restarting several times.  But since then, I am unable to connect to the Internet in the terminal or GUI.    There is a chatroom  about my issues.  sudo nmcli c up <saved WIFI connection>   only appears to connect.   sudo nmcli d wifi list   shows strong signal strength, but ping to google and nyt fails.   The phone I use as a hotspot shows a successful connection.    In the GUI Network Tools show the phone/hotspot recently used minutes ago, the Available Networks list shows the phone/hotspot as available with a check mark, but the "connect" button is grayed out and unfunctional.    REGDOMAIN=00 and attempts to change this has failed as others describe. I have a similar set up to the one described by cipricus in  and the situation described in


Write complex citations with BibLatex - "&" needed instead of "and"

Using BibLatex with the apa style I try to cite some references in the following way:     ... slightly adapted Biggs’ (1987, 1999; see for a similar model Marsick, Watkins, & O’Conner, 2011) model of ...   I tried to get the result as following (MWE)   \documentclass[a4paper,10pt]{article} \usepackage[utf8]{inputenc} \usepackage[style=apa, backend=biber, sortcites=true]{biblatex}  \usepackage{filecontents}  \begin{filecontents}{\jobname.bib} @book{biggs1987,     location = {Melbourne},     title = {Student approaches to learning and studying},     publisher = {Australian Council for Educational Research},     author = {Biggs, J.},     date = {1987} }  @book{biggs1999,     location = {Buckingham},     title = {Teaching for quality learning at university. What the student does},     publisher = {Society for Research into Higher Education},     author = {Biggs, J.},     date = {1999} }  @incollection{marsick2011,     location = {London},     title = {Researching workplace learning in the United States},     pages = {198--209},     booktitle = {The international handbook of workplace learning},     publisher = {Sage},     author = {Marsick, Victoria and Watkins, Karen and O'Conner, Bridget N.},     editor = {Malloch, M. and Cairns, L. and Evans, K. and O'Conner, Bridget N.},     date = {2011} }  \end{filecontents}  \addbibresource{\jobname.bib}  \begin{document}  \ldots slightly adapted Biggs' (\citeyear{biggs1987, biggs1999}; see for a similar model \citeauthor{marsick2011}, \citeyear{marsick2011}) model of  \ldots  \end{document}   However, the output is only:     ... slightly adapted Biggs’ (1987, 1999; see for a similar model Marsick, Watkins, and O’Conner, 2011) model of ...   As you see BibLatex prints an "and" instead of an "&". It seems as \citeauthor is only thought to be used as in-text citation (there the "and" is correct).  I guess I could make my life a little bit easier by using the natbib option (see ). However, that changes some formations that I don't want to have changed.  My question therefore is: How do I get the ampersand (&) into the my citation without globally changing the and for in-text citations?


i have a HTML page that include in a iframe another page, like this:  <!DOCTYPE html> <html> <head>     <style>         iframe{width:100vw;height:100vh;border:0}     </style>     <script>         function reload(){setTimeout(function(){document.body.firstElementChild.src+="",reload()},300000)}reload();     </script> </head> <body> <iframe id="mappa" src="*********"></iframe> </body> </html>   Now i want to run a command into in this iframe, like this: $(".SimpleSliderDecrementButton").trigger("click");  How can i made this command running into the iframe?


Running echo "Hello world!" in bash:  # echo "Hello world!" -bash: !": event not found   Why does bash complain "!": event not found"? No !, everything is OK:    # echo "Hello world" Hello world   Update: My bash version:    # bash --version GNU bash, version 4.2.46(1)-release (x86_64-redhat-linux-gnu)


For natural $n$, prove $\prod_{k=1}^n \tan\left(\frac{k\pi}{2n+1}\right) = 2^n \prod_{k=1}^n \sin\left(\frac{k\pi}{2n+1}\right)=\sqrt{2n+1}$

Prove that, for a natural number $n$,   $$\prod_{k=1}^n \tan\left(\frac{k\pi}{2n+1}\right) = 2^n \prod_{k=1}^n \sin\left(\frac{k\pi}{2n+1}\right)=\sqrt{2n+1}$$   This follows from a continued fraction identity for which, I think, there is a lengthy proof. But, I thought, that there may be a direct geometric or another proof. Constructing a polynomial with the sines and tangents roots may be helpful.


Multiple option arguments using getopts in bash

I am trying to process command line arguments using getopts in bash. One of the requirements is for the processing of an arbitrary number of option arguments (without the use of quotes).  1st example (only grabs the 1st argument)  madcap:~/projects$ ./getoptz.sh -s a b c -s was triggered Argument: a   2nd example (I want it to behave like this but without needing to quote the argument"  madcap:~/projects$ ./getoptz.sh -s "a b c" -s was triggered Argument: a b c   Is there a way to do this?  Here's the code I have now:  #!/bin/bash while getopts ":s:" opt; do     case $opt in     s) echo "-s was triggered" >&2        args="$OPTARG"        echo "Argument: $args"        ;;        \?) echo "Invalid option: -$OPTARG" >&2        ;;     :) echo "Option -$OPTARG requires an argument." >&2        exit 1        ;;     esac done   Note that I want to support multiple flags this way, e.g.  madcap:~/projects$ ./getoptz.sh -s a b c -u 1 2 3 4 -s was triggered Argument: a b c -u was triggered Argument: 1 2 3 4


TikZ-Feynman: Orientating diagram horizontally

I want to make a Feynman diagram using the Tikz-Feynman package, that is aligned horizontally. The command I use looks like:  \documentclass{book} \usepackage{tikz-feynman} \usepackage{tikz} \usetikzlibrary{shapes,arrows,positioning,automata,backgrounds,calc,er,patterns} \tikzfeynmanset{compat=1.0.0} \begin{document} \begin{center} \feynmandiagram[horizontal=a to b]{   i1 -- [fermion] a -- [fermion] i2,   a -- [photon] b,   f1 -- [fermion] b -- [fermion] f2, }; \end{center} \end{document}   According to the documentation, this should look like this:   but instead it looks like this:    How do I fix this?  PS: I am using a Sharelatex installation on my own server to compile the document.


Is there a way to ask the ordinal number value in English without sounding weird?

If the answer expected is It is an amazing car, then the question would be How is the car?  If the answer expected is I got my red car then the question would be something like Which colour car did you get? or Which car did you get?  BUT if the expected answer is This is my third car / This is my ninteenth birthday, then what would the question be precisely? How would you frame it, if possible?  To clarify the importance of the precise question: So far, the only way I know how to elicit the above mentioned answer would be to hint it in the question itself, like Is this you twentieth birthday?, and then they would answer No, this is my ninteenth birthday.


How to 'linkify' plain text URLs (locally) on the Mac?

I'm copying a slab of plain text that contains URLs into an RTF file in TextEdit, which I am hoping to automatically, (as there are a lot of them in the text), 'linkify' into rich text hyperlinks - make them clickable, and underlined in blue or as per the default appearance.  In WordPad on Windows, if you paste plain text, WordPad will automatically linkify any links, but TextEdit, Word 2011, and Pages on the Mac all will not.  I've also tried to export the text to PDF in TextEdit, Word 11 and Pages and fiddled around with Tools in Acrobat Pro itself - all to no avail.  An AppleScript would be fun, but (even if hooked into FastScripts), still not as quick or elegant as Windows' WordPad's instant and automatic linkification of URLs upon insertion into a document.  Is there something this elegant in OS X?


How to round off fractional part in java

I have to divide 495/116533, i tried using long and double; but it's returning 0.0;  Once if i able to capture that value (0.004247) then i can use round of methods; Please help me how to capture complete value( which data type it supports?)


Little did I suspect that she would sign a new contract.(inversion)

Why is it inversion? We use DID after the word LITTLE. If I see another example,I'll understand .So-Not until we saw our kids with our own eyes did we believe they were really safe and sound- in that case DID stay after -we saw...And It's wrong.


In SharePoint I can set my "Created By" column to display as "Office", which then shows as this.    My problem is, that I cannot figure out a way to pull what is displayed here to use for a condition in a flow.  SharePoint will not allow me to use "Created By" in a calculated column.  Also nowhere in the flows dynamic content is there a "Created By Office".  Does anyone have any ideas? Please, I have been on this for days now.


Count groups of characters in string using Java

Basically I am reading a string patterned like AABBCCAACC; how can I count how many times has each group of 2 characters been typed in by the user?  I have tried this without success:  for (int i = 1; i < str.length(); i+=2) {   if(str.substring(i, i+1) == "AA");   {     countAA++;   } }


Why does Sauron send Grishnakh instead of a Nazgul to deal with Saruman's Uruk-hai?

This again is another strange decision on Sauron's part, we know from Grishnakh and the fact Legolas killed a fell beast that there is at least one Nazgul on the eastern side of the Anduin, possibly more. Now in both Saruman and Sauron's case they know that a halfling currently holds the one ring, so they naturally think Merry or Pippin has it, as their the only halflings the Uruk-hai, northerners and possibly Mordor orcs come across at Amon Hen.  Now from my personal point of view it is likely Sauron learnt from the orcs on the eastern bank of the Anduin or merely guessing (we know he finds Saruman easy to predict) that Saruman has sent his own band of merry Uruk-hai to capture and deliver the hobbits to Isengard, so himself sends Grishnakh and maybe a few other Mordorians he make sure Ugluk actually takes the hobbits east. Grishnakh himself learns that Ugluk represents the white hand and out numbers him by a lot so Grishnakh then slumps off for a bit and returns with 40 Mordorians with him.  Now why i find this so strange is down to the fact Sauron risks letting a rival having the ring (from their view, we know Frodo in fact has the ring) by sending an orc messenger who is heavily outgunned, even though he has at least one nazgul on the eastern bank of the Anduin ( personally i think there is more than one waiting). Now the main argument against myself is that Grishnakh reveals the winged Nazgul of forbidden in showing themselves across the Anduin, but we know they could cross in secret and use horses instead of the giant fellbeast.  So why does Sauron send a lackey instead of an actual power to get the ring?


How do I confirm that I have found the correct package name?

I appear to be experiencing a bug with 'Backups' and wish to report it. , I must . However, given a list of possible options, how do I know which one it is?  Namely, I surmise in this case it is 'deja-dup', but I wish to confirm before filing the bug report. How do I so?  $ sudo apt-cache search backups [sudo] password for user:  backuppc - high-performance, enterprise-grade system for backing up PCs deja-dup - Back up your files rsync - fast, versatile, remote (and local) file-copying tool tar - GNU version of the tar archiving utility [roughly one hundred other options are listed]   Trying a different search method:  $ apt search backups | grep installed | cat -b  WARNING: apt does not have a stable CLI interface. Use with caution in scripts.       1  deja-dup/xenial-updates,now 34.2-0ubuntu1.1 amd64 [installed]      2  rsync/xenial-updates,xenial-security,now 3.1.1-3ubuntu1.1 amd64 [installed]      3  tar/xenial-updates,xenial-security,now 1.28-2.1ubuntu0.1 amd64 [installed]   My only guess on how to confirm is to try executing the command hoping to open the same 'Backups' Graphical User Interface, but it appears dangerous or poor practice to execute commands without knowing what they will do.


What is the difference between these functions? And what are the advantages and disadvantages?  let Test = function(name) {   this.name = name;   this.complete = function() {     console.log(`completing task${this.name}`)   } }   and  let Test = function(name) {   this.name = name; }  Test.prototype.complete = function() {   console.log(`completing task${this.name}`) }


Retrieving Element of a List with Name instead of n-th element

I am unsure how to gather different dataframes under "the same roof". I thought it might be a good idea to create a list, in which each element is a dataframe (if there is a more convenient way, please enlighten me). To give an example of how I created this list:  import requests import pandas as pd tic_in = ['AAPL', 'AMZN']          # list for feeding url   list_test = [] for ticker in tic_in:    url = 'https://www.stocksplithistory.com/?symbol=' + str(ticker)     html = requests.get(url).content    df_list = pd.read_html(html)    df = df_list[7]                       # 7th table is what I want                        list_test.append(df)                  # append new dataframe to list   Now my problem: If I want to access any of these dataframes, I have to work with the n-th element. Speaking: If I e.g. want to retrieve the dataframe of 'AAPL', I have to:  list_test[0].head()   Is there a possibility to somehow give a position of a list a name? So I could avoid working with the n-th element, and instead work with the more direct way:  list_test['AAPL']   (Im new to this forum, thank you very much)


What was the largest object ever manipulated by the force?

When Luke is undergoing training on Dagobah, he famously tries and fails to lift his X-Wing from the swamp:     LUKE: I can't.  It's too big.      YODA: Size matters not. Look at me. Judge me by my size, do you? Hm? Mmmm.   Yoda then lifts it for him and the story continues.  Now, while Yoda says size matters not, I'm assuming there are limitations. In other words, I'm assuming a Jedi can't stand aboard a spaceship and lift/manipulate an entire planet. Or can they? Or how about something even smaller - could a Jedi lift/manipulate a Coruscant skyscraper?  What was the largest object every manipulated using the force in the Star Wars universe, books, movies or otherwise? I'd be interested in either largest as in size, or largest as in weight.


Why does partial differentiation give centre of a conic?

Definition of centre of conics states that, "The point which bisects every chord of the conic passing through it is called centre of the conic"  General equation of second degree is $S:ax^2+2hxy+by^2+2gx+2fy+c=0$ If we partially differentiate $S$ with respect to $x$ and $y$, and then set both partial derivatives to $0$  . Solving two equations give centre of conics. Could someone explain simple logic behind this approach i.e. why we get centre using above methodology?


US Dollar (USD) to Nicaraguan Córdoba (NIO) exchange rate

I have heard that the exchange rate of Nicaragua's currency is "pegged" to the US dollar, and varies at a fixed, predicable rate rather than varying naturally with the markets. What is the rate currently, and how can I find what the rate will be for a given date in the future?


Prove $p_n(x) \rightarrow \sqrt{x}$ uniformly as $n \rightarrow \infty$

Define $(p_n)_n$ recursively by $p_0(x) = 0$ and $p_{n+1}(x) = p_n(x) + \frac{1}{2}(x - p_n(x)^2)$.  Prove that $p_n(x) \rightarrow \sqrt{x}$ uniformly for $0 \leq x \leq 1$ as $n \rightarrow \infty$.  I'm not sure where to go with this.  I can show inductively that $\forall n,\  0 \leq p_n(x) \leq 1$ for $0 \leq x \leq 1$, and I think that $p_n(x)$ is increasing with $n$, but I have no idea whether this helps me.  I know that I need to show that $\forall \epsilon>0: \exists N \in \mathbb{N}: \forall n \geq N: \forall x\in [0,1]: \big|p_n(x) - \sqrt{x}\big| < \epsilon$ Edit:  I just had a thought.  I'm given a version of Dini's theorem that reads  Let $X$ be a compact metric space, $(f_n)_n$ a sequence of real-valued continuous functions on $X$, $f$ a continuous function on $X$ such that: (i) $f_n \rightarrow f$ pointwise on $X$, and (ii) $f_n(x) \geq f_{n+1}(x) $ for all $x \in X, n \in \mathbb{N}$. Then: $f_n \rightarrow f$ uniformly on $X$.  Obviously, (ii) is not true for my sequence, but what if I took $f_n(x) = -p_n(x)$ and $f(x) = - \sqrt{x}$?  Then I could prove (ii) to be true, I know that $[0,1]$ is compact, and $f_n(x)$ is real-valued.  The only part I would need to prove is (i), which is where I get confused.  Correct me if I'm wrong, but after that I could say that since $(-p_n)_n \rightarrow -\sqrt{x}$, then $(p_n)_n \rightarrow \sqrt{x}$.  Any advice?


Checking my Native backup this morning something wierd happened. I will describe the problem here.  1) The msdb table backup set shows me the backup was done successfully.  2) The errorlog shows me that the backup was done successfully.  3) The job history doesn't show any entry, even it is successfully or error.  4) Checking the backup media family table the physical device name column shows me something like this: {F2F1E11C-589A-4AAE-8880-0120D8D1998D}1 and other days it shows me the right directory of my backups.  4) The DPM also do system state and database backup after the SQL Server Backup and runs well.  Well.. if anyone need more informations, please let me know.  Thanks. Marcos Freccia @SqlFreccia


GRE exam word problem: show that a higher percentage of total agricultural acreage was fallow in United States than in the Soviet Union.

A ten year comparison between the United States and the Soviet Union   in terms of crop yields per acre revealed that when only planted   acreage is compared, Soviet yields were equal to 68 percent of United   States yields. When total agricultural acreage (planted acreage plus   fallow acreage) is compared, however, Soviet yield was 114 percent of   US yield. From the information above, show that a higher percentage of   total agricultural acreage was fallow in United States than in the   Soviet Union.   Proof:  Let $USP$ for US planted and $SUP$ for Soviet Union planted. The same for $USF$ and $SUF$. We know that $SUP/USP= 0.68.$  How does the sentence     When total agricultural acreage (planted acreage plus fallow acreage)   is compared, however, Soviet yield was 114 percent of US yield.   imply that  $(SUF+SUP)/(USF+USP)= 1.14$? (that's the next step of the proof which is the part I'm stuck)


How do I find out what fields are required when I create a record in Salesforce using SOQL?


Show $\operatorname{Hom}_{\mathbb{Z}}\left ( \mathbb{Z}/n\mathbb{Z},\mathbb{Z}/m\mathbb{Z} \right )\cong \mathbb{Z}/\left ( n,m \right )\mathbb{Z}$

Show that $\operatorname{Hom}_{\mathbb{Z}}\left ( \mathbb{Z}/n\mathbb{Z},\mathbb{Z}/m\mathbb{Z} \right )\cong \mathbb{Z}/\left ( n,m \right )\mathbb{Z}$  I think that the hom-set (of $\mathbb{Z}$ module homomorphisms ) is isomorphic to $\left \{ a\in \mathbb{Z}/m\mathbb{Z},na=m\mathbb{Z} \right \}=\left \{ k+m\mathbb{Z} \right \}$ where $m\mid (nk)$ but I can't show that it's isomorphic to $\mathbb{Z}/\left ( n,m \right )\mathbb{Z}$


generate simple cylindrical shape with text in latex (tikz)

I am attempting to generate the following diagram in latex:    I've been using the tikz package, which although its capabilities seem to be endless, it does have a rather steep learning curve. I am currently learning how to generate simple diagrams including circles, arrows, squares, and have no idea how to include text yet. I am working through the manual so I will eventually have a good understanding of the tool, but as of yet, the diagram shown is beyond my capabilities. Could someone specify how I should go around generating this diagram? Many thanks for your help.


How to perform Multipath TCP for bandwidth on Windows® 10?

I’m in a situation where I have an ADSL connection over Ethernet and I can use an open Wi‑Fi access point of my neighbour, who has fiber.  I can connect to both networks at the same time, but because of the default gateway rules, all outgoing Internet connections are performed using only one adapter at time. The aim is not only to perform load balancing but to really merge the two bandwidths for a single data stream.  How to perform Multipath TCP for bandwidth on Windows® 10 ?   explicitly asks for a hardware solution, whereas I need a software one especially due to Wi‑Fi.


I'm doing Blender Guru's Chair on yt. At one point he isolated a part so we could work on the seams. Now I can't seem to exit the Isolation mode for this part? In Layout Mode it's stuck but in all other modes I can see the parts. I've tried Alt+H and Ctrl+H and 'H' on it's own but nothing seems to change. The outliner shows the parts as visibile.  Any Ideas?  David  Layout Mode - Brace 1 is isolated but other parts are visible in outliner:   All parts visible in other modes


Find $$S=\sum_{r=1}^{3n-1}{ (-1)^{r-1}r\over{3n \choose r}},~ \text{if $n$ is even}$$  The answer given to me is ${3n\over3n+2}$ , the main problem I am facing is that the binomial coefficients are in the denominator, and so I can not use any of the usual techniques I used to use , like using integration or different on any binomial series. Although I tried by rewriting the sum in reverse order and then adding it to the original expression, this gave me : $$2S=3n\sum_{r=1}^{3n-1}{ (-1)^{r-1}\over{3n \choose r}}$$ This is sure simpler than the original problem but still no good , I could not figure out a way to solve the rest . Could someone please help me in solving thi problem ? Thanks !


I am trying to access the GRUB from my ubuntu installation as shown here:   But I get the following result. How can I get to the GRUB? Any Idea?   Adding the output of cat /etc/default/grub   # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: #   info -f grub -n 'Simple configuration'  GRUB_DEFAULT=0 GRUB_TIMEOUT=0 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="nomodeset" GRUB_CMDLINE_LINUX=""  # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"  # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console  # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480  # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true  # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true"  # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1"


Normal approximation to the binomial distribution

I am having trouble getting to the bottom of this concept for two types of questions (hw is already passed, but I have a test this week and would like to do better).  Hopefully someone can help me get this through my thick skull.  Question 1     In the following problem, check that it is appropriate to use the   normal approximation to the binomial. Then use the normal distribution   to estimate the requested probabilities.      Do you try to pad an insurance claim to cover your deductible? About   39% of all U.S. adults will try to pad their insurance claims! Suppose   that you are the director of an insurance adjustment office. Your   office has just received 134 insurance claims to be processed in the   next few days.       (a) half or more of the claims have been padded   Question 2     Based on long experience, an airline found that about 6% of the people   making reservations on a flight from Miami to Denver do not show up   for the flight. Suppose the airline overbooks this flight by selling   272 ticket reservations for an airplane with only 255 seats.       Use the normal approximation to the binomial distribution to answer:   What is the probability that a seat will be available for every person   who shows up holding a reservation?     Adding per the comments posted.  My understanding of the approximation is that given np > 5 and nq > 5 the approximation can be used, and I have in my notes the definitions of   Mean = np   Sigma = Sqrt(npq)   Nowhere does it discuss how to figure out a probability, so I assume I use the probability from the binomial distribution (is this correct)   P = nCk * p^k * q^(n-k)   But my other issues is that binomial distribution is for exactly k successes out of n attempts. That doesn't seem to be the problem for question 1 (but I suppose I could sum all of the k..0 (by -1) successes.  But again I am a touch confused here as well.  Looking at  question 2 it is more of the same, what is the probability that more than 255 people will show up .  Maybe my question is more around the application of the binomial distribution.  The textbook (brase and brase) is not super strong and I have been trying to augment with web and other texts.  I am taking this as a leading class in a graduate degree in Econ.  I also have a team of computational finance guys that work indirectly for me, but I would like to be able to have better conversations with them, and I have always wanted to now more about probability.  At the end of the day, I got a 94 on this hw assignment (so its not like this is killing my grades), but these two questions (with a few more parts to them) really stumped me.  It seems like a trivial place to get stumped and I would hate for this to come back and bite me later on!    I think if I approach it this way:  p = .39 q = 1 – p n = 134 Mean:  52.26 (approximated by np) Sigma: 5.6 ( approximated by: sqrt(npq) )  test = 134 / 2 = 67  P(x > 67)  ~= P(x > 66.5)                                                the continuity correction ~= 1 - p(z > (x – mean) / sigma)  ~= 1 – p(z  >  (67 - 52.26) / 5.6)   thoughts?


High Level Elementary Statistics Textbook

I am looking for an elementary statistics book, that contains topics such as descriptive statistics, sampling distributions of the mean and variance, etc. However, despite my interest in basic topics, I am looking for a book that teaches it in a high level, for example: when discussing the why the variance includes a squared difference from the mean and not absolute value, I am looking for a mathematical explanation (the problem with the derivative), or, a loss function explanation. In other words, I am looking for an elementary statistics book for mathematicians or statisticians, and not just a textbook. Can you please recommend me of such books, if exist? Thank you.


Is it right to place a icon and text together?

I'm working on an admin dashboard design, for some shipping transports. I've designed couple of dashboard before. Everytime i was asked this question.  Normally in dashboard design we will place icon as well as text together right? Is it right to have both the things together? if yes or no, why?


Finding the integral $\int_0^1 \frac{x^a - 1}{\log x} dx$

How to do the following integral:  $$\int_{0}^1 \dfrac{x^a-1}{\log(x)}dx$$ where $a \geq 0$?  I was asked this question by a friend, and couldn't think of any substitution that works. Plugging in a=2,3, etc in Wolfram, I get values like $\log(a+1)$, which may be the right answer (for general $a$). Is there a simple way to calculate this integral?


Context of this problem: $\sum_{n\,\text{odd}} (-1)^{\frac{n-1}2}\frac{\log n}{\sqrt{n}} /\sum_{n\,\text{odd}}(-1)^{\frac{n-1}{2}}\frac{1}{\sqrt{n}}$

I remember seeing this somewhere a while ago - I'd given it a go but it was - and still is - beyond my capabilities. The problem came with the tag: "requires knowledge of analytic number theory". I am not necessarily asking for a solution.  $$\left[\;\sum_{n\;\text{odd}} (-1)^{\frac{n-1}{2}}\frac{ \log n}{\sqrt{n}} \right]\left[\;\sum_{n \;\text{odd}} (-1)^{\frac{n-1}{2}}\frac{1}{\sqrt{n}} \right]^{-1}$$ Does anyone know where this is from? I am equally puzzled by the "hint". Does it have a number-theoretic interpretation that someone with basic (i.e. olympiad-level) knowledge of number theory could understand?  Would appreciate a reference if this appears in the literature somewhere.


Writing test case for class that has a process flow

Trying to wrap my head around this one.   I have a custom object managed by an apex class that has a Process defined along with it. This process has an immediate action that calls an apex class that effectively does equivalent of webhook.  When I write a testClass for it, doing a basic CRUD test, it fails with this message: Methods defined as TestMethod do not support Web service callouts  How does one write a testcase for this?  adding some code:  public class with sharing WebHook {    public class Ids {        @InvokableVariable(label='Id')        public String idfield;    }     @InvokableMethod    public static void postIt(List<Ids> ids) {       Ids aid = ids[0];       Map<String, String> m = new Map(...);       m.put('idfield', aid.idfield);       System.enqueueJob(new QueueableCall('http://localhost:8000', 'POST', JSON.serialize(m)));    }     public class QueueableCall implements System.Queueable, Database.AllowsCallouts {          private final String url;         private final String method;         private final String body;          public QueueableCall(String url, String method, String body) {             this.url = url;             this.method = method;             this.body = body;         }          public void execute(System.QueueableContext ctx) {             HttpRequest req = new HttpRequest();             req.setEndpoint(url);             req.setMethod(method);             req.setBody(body);             Http http = new Http();             HttpResponse res = http.send(req);         }      } }  public class with sharing ClassA {     public static void addA(String a, String b) {         ObjA a = new ObjA();         a.a = a;         a.b = b;         insert(a);     } }   I'm trying to write a testclass for ClassA and it's erroring with message at top. How do I write tests for WebHook and QueueableCall to complete this test?


How do you launch the JavaScript debugger in Google Chrome?

When using Google Chrome, I want to debug some JavaScript code. How can I do that?


I'm having some trouble changing the colors of parts of an equation in Beamer, with "math text" being set. The following MWE demonstrates the example:  \documentclass{beamer} \usepackage{color} \setbeamercolor{math text}{fg=blue}  \begin{document} \begin{frame}{Frame}     $x \alert{\cong} y \alert{=} z$ \\     $x \textcolor{green}{\cong} y \textcolor{green}{=} z$ \\     $x {\setbeamercolor{math text}{fg=green}{\cong}} y {\setbeamercolor{math text}{fg=green}{=}} z$ \end{frame} \end{document}   I would expect both symbols in the first and second line to get colored. However, for some reason, \cong is not colored, but = is. Is there some way to make coloring work reliably with all math symbols?  I found another Stackexchange question () where people suggested the code I used in the third line - which, confusingly, works for \cong, but not for =.  For now, I replaced \cong by \stackrel{\sim}{=}, but really that's just a work-around, and if this ever happens with a symbol I cannot reconstruct otherwise, I'll be in trouble.


I use the term "100% crop" to mean a portion of a picture that has been cropped but not resized, but I have also seen some confusion around that term.   Is there an accepted definition for "100% crop?" What is its opposite called?   Here's what I think it means:   If I'm right, what is the proper name for "something else?" If I'm wrong, please include illustrations.  Either way, what evidence supports the definitions?


Why is it easier to ride a bicycle than to run?

While it is very hard and energy-consuming to run a marathon, covering the same distance by bike is doable by most people. Where exactly does the gain come from?  Assuming for simplicity that we are on a flat surface, all the expended energy eventually dissipates, i. e. is used to produce work against friction. I can see the following possible explanations of why walking/running could lead to less efficient setup:   when running, at each step one needs to  lift their center of mass, turning the energy into potential energy, which is then dissipated; when the front foot reaches the ground, it moves in the forward direction until friction stops it, dissipating its kinetic energy; our joints are just less suited for walking than for spinning peddles and dissipate more energy doing that.   So, I would like to know which of these reasons really contribute/are dominant? Or maybe there are some other reasons I did not think of? Are there some fundamental obstructions for walking to be more efficient, or is it just an "engineering" issue?  UPD: turns out this question has already been , which I somehow didn't manage to find before asking. See also  to another duplicate question.


Give askers a way to challenge a duplicate closure

When I read about Stack Overflow or the Stack Exchange network in various other places on the internet, a lot of it are complaints about the moderation. There is one specific complaint I see a lot, and that is that questions are wrongly closed as duplicates.   Getting their question closed as a duplicate should actually make users happy, it is in many cases an even better response than an direct answer. A proper closure as an exact duplicate means there is already a hopefully excellent answer to their question, and we just told them where to find it. And a frequent duplicate target is likely to be a much better answer than something a user wrote quickly just for the new question.  But it does seem that users are often not happy to have their questions closed as a duplicate. While I suspect that the extent of complaints I've seen about this exaggerates the problem, I have seen a fair share of overzealous and careless duplicate closures, that aren't actually exact duplicates.  There is a way to get your question reopened, by editing it and putting it into the reopen queue. But that is not obvious or transparent to new users in any way.  What I propose is to show the asker a dialog similar to the existing one shown for questions with duplicate close votes that are still open, where the user can short-circuit the voting and close the question immediately. The user would have two options in this case for their closed question:   Great, the duplicate answers my question. Thanks! The duplicate does not answer my question, my question is actually different, please reopen it.   If the user clicks on the option challenging the closure, it probably makes sense to also require them to edit it at that point and clarify how it is different from the duplicate. And then the question would be put into the reopen queue.  I've no idea how often this would be misused for proper duplicate closures. But then, this feature would also provide us with statistics about how many of these closures are perceived as wrong by the askers, and what the community thinks about those and whether they are reopened.


How can I prove $\sup(A+B)=\sup A+\sup B$ if $A+B=\{a+b\mid a\in A, b\in B\}$

If $A,B$ non empty, upper bounded sets and $A+B=\{a+b\mid a\in A, b\in B\}$, how can I prove that $\sup(A+B)=\sup A+\sup B$?


im fairly new to neural networks. I want to ask what exactly does the activation output, is it the probability the combined summation of inputs and weights lead to a match for the next neuron? Thanks


Take $z_1,z_2 \in \mathbb{C},$ and assume $|z_1| < 1, |z_2| < 1.$ I want to prove that $$\left|\frac{z_1-z_2}{1-\bar{z}_1z_2}\right| < 1.$$ Take $z_1 = x+iy, z_2 = a+ib$ for $x,y,a,b \in \mathbb{R}.$ We see that $$|z_1| < 1 \implies \sqrt{x^2 + y^2} < 1 \implies x^2 + y^2 < 1.$$ similarly we see that $$|z_2| < 1 \implies \sqrt{a^2 + b^2} < 1 \implies a^2 + b^2 < 1.$$ We see that $$\left|\frac{z_1-z_2}{1-\bar{z}_1z_2}\right|  =\left|\frac{(x-a) + i(y-b)}{1 -(x-iy)(a+ib)}\right|  =\left|\frac{(x-a) + i(y-b)}{1 -(xa + ibx -iay + yb)}\right|  =\left|\frac{(x-a) + i(y-b)}{(1-xa-yb) + i(ay - bx)}\right|.$$ However, I am beginning to have some issues as to how to simplify this to a non-fraction. Any recommendations?


RMSE vs Standard deviation in population

RMSE (Root mean square error) and SD (Standard deviation) have similar formulas.   says     The only difference is that you divide by  $n$ and not  $n−1$ since   you are not subtracting the sample mean here. The RMSE would then   correspond to  $\sigma$ . Therefore, the population RMSE is  $\sigma$   and you want a CI for that.   So I want to know whether RMSE and SD are the same. Also, I want reference about it.


How can I get TeXLive 2014 on Debian wheezy (stable)?

Debian wheezy's (stable) repositories only have TeX Live 2012 -- what is best practice for getting TeX Live 2014?


Good day Ubuntu community, I'm a Master of Law, currently studying Data Science, after a Bachelor in Business Informatics. I am not that new to coding and my new field of studies requires me to switch to Linux for obvious reasons, the problem is i have nave used anything other than Windows and I have a very rare laptop- Dell Latitute 5420 Rugged. There are close to no topics on the internet about such a laptop using Linux, so I'm unsure if it will be good or will i have too many ports and features not working on Linux, for example it has LED keyboard, supports 2 batteries, has Fingerprint sensors and Face recognition, Touchscreen display etc. Can someone help me decide if I should do it and whether those things will keep working after switching to Ubuntu?


Is the number 1.1010010001... transcendental?

Consider the number 1.1010010001... defined as 1.1 followed by linearly increasing numbers of zeroes separated by ones. This number must almost certainly be irrational, but is it also transcendental?  $$\sum_{i=1}^\infty 10^{-(i^2 -i)/2}$$  The number is superficially similar to Liouville's constant, but instead of containing a factorial in the sum there is a combination which is equivalent to (n-1)n/2, somewhat simpler algebraically.  It also appears to be related to the Jacobi-theta function.  If this constant is indeed irrational and transcendental what would be the best way to go about proving this?


R-squared: X "explains" the percentage of variation of the Y values. Does axis order matter?

Summary:  Am I correlating two independent variables?   Is that the problem?  Let's say I have data point for square footage of a house and the asking price.   Now, I can ask "Does square footage (x) determine price (y)?"  This is intuituve, and makes sense.  R-squared would end up saying "Square footage explains X% of the variation in price".  So far, so good.  But, what if I want to predict the square footage from the price?  That seems valid.  Now, I ask "Does price (x) determine square footage (y)?"  So far, it seems either can function as the independent or dependent variable.  However, the wording or r-squared seem off.  "Price explains X% of the variation in square footage".  Huh?  Square footage is not some sort of multi-factor variable.  It's more static.  Nothing "explains" the square footage, it just is.  Get what I'm saying?  Like if price only explains x% of square footage, what else would explain square footage?  Square footage is just square footage.  It's not like price, which can be determined by many things (square footage, renovations, size of yard, etc).  Another example can be age (x) and the mileage on a car (y).  With a regression equation, I can use one to predict the other.  Either order seems to work.  However does age "explain" the mileage, or does mileage "explain" the age?  In this case, both seem weird.  Both are just static independent variables.  Neither explains the other, if you ask me.  What am I missing here?  Thanks!


Classifying raw LAS data as bare earth in ArcGIS for Desktop?

I have a raw LAS data that has only one return (no second/ third.. return) and not classified yet. The only information I have is intensity and elevation. Is there any way that I can classify bare earth in ArcGIS? (vendor does not have more info than that). I tried classifying by selection from the profile view, but I know it is impossible to apply to all data.


You will see here:    What is the trick with modulus for proving irrationality?  What about $\sqrt{2}$  Can you prove this is irrational by that trick?


If we reverse the digits of $12$ we will get $21$. $12^{2}=144$. If we reverse its digits we will get $441$ which is $21^{2}$.  Here is the puzzle. How many such two digit numbers are there? Digits must be different.  We got an algebraic method to solve it if the square is a three digit number.It given here :  Let $a>b$  $(10a+b)^{2}=100x+10y+z$ and $(10b+a)^{2}=100z+10y+x$  Difference between these two equations will lead to $a^{2}-b^{2}=x-z$  $x-z \leq 8$.Then  $a^{2}-b^{2} \leq 8$.  Since squares are of three digits $a <4$.But since $a>b ,a \neq 1$.  $b=1 \Longrightarrow a^{2} \leq 9$.Then $a=1,2,3$ but only possibilities are $2 $ and $3$.  $b=2 \Longrightarrow a^{2} \leq 12 \Longrightarrow a= 1,2,3$. But possibility is $a=3$. So next such pair will be $13,31$.  Higher values of $b$ will not work since $a$ cannot exceed 3. This is an explanation we obtained from a mathematics group.It works well if the square is a three digit number.What will happen if square is a 4 digit number... Or if we try to extend this problem for numbers having more than two digits ?


Suppose that I moved from BibTeX to biblatex. With BibTeX I just copied the content of .bbl file into final version of my paper before submitting it to a journal. What should I do at same stage having .bbl file produced by biblatex? It is of quite different format.


My Sites Link in Search Resuls is Incorrect (Escaped)

I've setup MySites in SharePoint 2013 and created some test sites. Everything seems to be working well except on searching people. Using search center finds the person and the link's backslash is escaped.      http://mysiteshost/Person.aspx?accountname=DOMAIN%255CUsername   This link fails to load with a "User Not Found" error. However, changing to:      http://mysiteshost/Person.aspx?accountname=DOMAIN\Username    works perfectly.  Any ideas?


How to cite a book chapter written by an author who is not the editor or author of the book with BibTeX?

I don't know how to cite a chapter written by an author who is not the editor or author of the book.   How can I get the following citation?     Grandstrand, O. (2004), 'Innovation and Intellectual Property Rights', in J. Fagerberg, D.C. Mowery and R.R. Nelson (Eds.), Oxford Handbook of Innovation. Oxford University Press: Oxford.


Let $f(x)$  be a twice-differentiable function on $(a,b)$,show that   there exsit $\xi\in(a,b)$ ,such $$\int_{a}^{b}f(x)dx=\dfrac{1}{2}(b-a)[f(a)+f(b)]-\dfrac{1}{12}(b-a)^3f''(\xi)$$  if this problem condition is Amuss that $f(x)$ is a three-differentiable function,  $$f(x)=f(a)+f'(a)(x-a)+\frac{f''(\xi_{1})\cdot (x-a)^2}{2}$$ $$f(x)=f(b)+f'(b)(x-b)+\frac{f''(\xi_{2})\cdot (x-b)^2}{2}$$ so $(1)+(2)$ $$\Longrightarrow 2f(x)=f(a)+f(b)+f'(a)(x-a)+f'(b)(x-b)+\dfrac{1}{2}[f''(\xi_{1})+f''(\xi_{2})][(x-a)^2+(x-b)^2]$$ since $f(x)$ is a three-differentiable function,so $f''(x)$ is  continuous,so there exsit $\xi\in(\xi_{1},\xi_{2})$,such  $$\dfrac{1}{2}[f''(\xi_{1})+f''(\xi_{2})]=f''(\xi)$$ $$\int_{a}^{b}f(x)dx=\dfrac{1}{2}(b-a)[f(a)+f(b)]-\dfrac{1}{12}(b-a)^3f''(\xi)$$ But if $f(x)$ have twice-differentiable,this methods is not usefull  Then I use this methods can't prove it.


Android app does not indicate closed questions until after you open them

While browsing sites using the Android app, I came in a question I happen to remember being closed. From the question list view, there is no indication that the question is closed. The title does not bear the usual [on hold] or [closed] markers. Starting in 0.1.24 the question itself now includes a fixed banner at the bottom of the screen indicating the question is closed and abbreviated information about why. The interface for this is quite clean, but you still have to be in the question view in order to learn this.  Edit: The on-question banner is still too subtle. It should be at the top of the screen and yellow as in the main site rather than at the bottom and grey. Also as of the latest version there is still no indication whatsoever of closed questions in the question list.


How to chian two External Monitors with Macbook Air 2017 13"

About the Mac:  Mac OS Mojave Version 10.14.4 (18E226)  MacBook Air (13-inch, 2017)   I wish to connect two external monitors with following specifications with my Apple device.   one pure HDMI  other VGA (converted to HDMI using a VGA to HDMI Adapter)   My device has one mini-display port. I have bought a (not an apple product) 3-in-1 mini-display port to (DVI, HDMI, VGA) adapter.  I have two options to connect.  1. Connect pure HDMI, VGA based monitors into one 3-in-1 mini-display port adapter. (FAILS!) 2. Connect the pure 3-in-1 Adapter to a splitter (another device that accepts one HDMI input and spilts into 4 HDMI outputs) using HDMI cable and then connect the two monitors using HDMI outputs. (WORKS!)   The second method is able to connect two monitors but my Apple device shows only one device connected in Display Settings and the two external monitors mirror each other but I want a chain display.  Any help?


Equality with Java generics: the subclass equals isn't called

I've got a Node<T> with an equals() method:  public boolean equals(Node<T> other) {     if (this == other)         return true;     if (other == null)         return false;     if (!obj.getClass().equals(other.getObject().getClass()))         return false;      return obj.equals(other.getObject()); }   I only care if the object held in my node is equal to the object held in the other node (because two equal objects can be held in different positions in my list).   The object I'm holding is a Token. The Token.equals() method works while my Node.equals() method does not:  public class TokenEqualityTest {     public static void main(String[] args) {         Token t = new Token(0);         Token q = new Token(0);         System.out.println("t.equals(q): " + t.equals(q));          Node<Token> tnode = new Node<Token>(null, null, t);         Node<Token> qnode = new Node<Token>(null, null, q);         System.out.println("tnode.equals(qnode): " + tnode.equals(qnode));     } }   which prints:  t.equals(q): true tnode.equals(qnode): false   If I put a breakpoint at Token.equals() and run the eclipse debugger, my code stops once (at t.equals(q)). This indicates that Node<Token>.equals() does not call Token.equals, and I have verified that the debugger does step through the line return obj.equals(other.getObject());.   Why doesn't my Node.equals ever call Token.equals when I've declared a Node<Token>?


Let $P(n)$ be the product of the positive integers which are $\leq n$ and relatively prime to $n$. Prove that   $$P(n) =  n^{\phi(n)} \prod_{d|n}{(d!/d^d)}^{\mu(n/d)}. $$


Excel: How to make certain cells "constants" so that they are not incremented when pasting a formula?

I would like to make cell A1 an input, column B an input, and column C to depend on A1 and column B, for example,  I have the value 5 in A1, and I want to set C1 = A1*B1, C2 = A1*B2, C3 = A1*B3, etc.  In other words, I want to not have to write 5*B1, 5*B2, etc. but have that be a user's choice. The problem I am having now is that even if I write the first few formulas for C1, C2, etc, and drag the "plus" sign (or paste special => formula only), excel doesn't note that I kept A1 constant, and will revert back to setting Cn = An*Bn, when I actually want Cn = A1*Bn.


Invisible text that can be seen only in PDF viewer

How to make text that is visible only in PDF viewer and disappears when printing?


In LaTex I build the following macro "kum" for translating arabic to german. The result are two minipages, left one with german, right one with arabic (the other two minipages were for design-issues). The macro "arab" is not shown, it just choose an arabic font.  \newcommand{\kum}[2]{ \begin{minipage}[t]{0.445\textwidth} \small #1 \end{minipage}  \begin{minipage}[t]{0.05\textwidth}   ~ \end{minipage} \begin{minipage}[t]{0.445\textwidth}  \begin{arab}[voc] \raggedleft #2 \end{arab} \end{minipage} \begin{minipage}[t]{0.06\textwidth}  ~ \end{minipage} }   Now I've two questions:   What is the equivalent of minipages in ConTeXt? How to realize the above LaTeX code in ConTeXt? (both with engine LuaTeX)


I am new to GIS and am trying to create my first map.  Could anyone recomend any good tutorials which are clear and simple? I am having difficulty importing my open source map information into my QGIS propgram. (I have had a look at the tutorial and online)


I have recently cancelled my visa4uk application because I applied for the wrong visa type. I already submitted my refund request and even email the Ukvi that cost me £5.60. They escalated my case today to the relevant department, does it mean refund would be on its way or there is still chances that refund might be rejected.   I submitted my application yesterday, paid for it and then cancelled the application within an hour.   Would my refund be approved?   Anyone has similar experience please advise.


Is the group $U(\mathbb{Z}_{54}) = \{1,5,7,11,13,17,19,23,25,29,31,35,37,41,43,47,49,53\}$ a cyclic group? If so, how do I show this? This group was found as a group of units of the monoid $\mathbb{Z}_{54}$.


How to check whether a String object is a link or not?

How a string object can be validate whether it is a link or not? I don't want to open any connection or network operation I just to want to check the pattern of string is matching to the pattern of a link or not. e.g       let str1 = "https://stackoverflow.com/questions/ask" // It is a link     let str2 = "https://stackoverflow.com" // It is a link      // Could be other combinations as well of a valid link      let str3 = "this is not a link" // Not a link    How to do that? Is It possible to check with regular expression or any other way or not possible?


$a+bx \leq f(x)$ for increasing and convex function $f$

Let $I \subseteq \mathbb R$ be an interval and $f:I \to \mathbb R$ increasing and convex. How can  I show that $f$ is bounded from below by an affine function, i.e. there exist $a \in \mathbb R$ and $b \in \mathbb R_+$ such that $a+bx \leq f(x)$ for all $x \in I$? What similiar statement would we have for concave function?


I want to install oracle-java8 on Ubuntu:

$ sudo apt-get install oracle-java8-installer Reading package lists... Done Building dependency tree        Reading state information... Done Package oracle-java8-installer is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'oracle-java8-installer' has no installation candidate


I have downloaded Ubuntu running Windows 7. How can checksum be run ?


Programmatically get the list of fields of a custom content

I want to programmatically create a custom content (custom content created via the admin UI). Before the creation, I want to check the types of fields of my custom content.  My custom content contains a field "body" (type text), a field "description" (type text), an int field (type int), an attached file field (type fid ?).  I tested several ways; this is my last try.  // I get the entity object "my_custom_content" $entity_object = NodeType::load("my_custom_content"); dpm($entity_object); //Work perfectly   $test = \Drupal::getContainer()->get("entity_field.manager")->getFieldDefinitions("my_custom_content",$entity_object->bundle())   The code returns an error:     The my_custom_content entity type does not exist.   With this $entity_object, how can I get the list of the fields of my custom content?  I see the EntityFieldManager class, the FieldItemList class, but I still do not understand how to play with Drupal 8.


I'm familiar with vertical filters, but wondered if it can be done so I would only show the the columns that matched my query.  Is it possible to filter horizontally in Google Spreadsheets?


There are many answers on the site discussing motion of electrons in an electric potential field,  See   but also mass tends to move toward a lower gravitational potential. I assume then that things in general tend to move toward a lower potential when the potential is defined so that it represents potential energy.  However sometimes "potential" is used for a field that another field can be derived from usually by taking a gradient.  See  for a discussion of the term "potential" in physics.  My question is:  Why physically do things in general tend to move toward a lower potential value in a potential field?  Do they in general? Is there a physical law? Is there a basic physical explanation? I know there are mathematical explanations. Does the potential have to be defined as potential energy for this to hold true? Also does this have to hold true if one field can be derived from another potential field. Etc. ..


I bought this computer one year ago and it came with Ubuntu 14.04 LTS. I used the computer as it came and I didn't have problems until now when I can't even download photos because the storage is full. In settings it says I only have 7,7GB s available even though on the computer specs it is 1TB. I ran lsblk in the terminal and it does show that I have 1TB of space but I can only use 7,7GB for some reason. How can I fix this? sda      8:0    0 931,5G  0 disk  ├─sda1   8:1    0   3,8G  0 part [SWAP] └─sda2   8:2    0   7,5G  0 part / sr0     11:0    1  1024M  0 rom


In the season 7 finale Euron Greyjoy asks "can they swim?" with regards to the wights, to which the reply was "no". When Viserion was hit by the Night King's javelin he fell, broke the ice and went into the water below.  How did the army of the dead recover Viserion (attach the chains to him) after he has been hit by the Night King's javelin?  As we have established that the wights can't swim, the only other explanation I can see is if one of the White Walkers swims down to attach the chains, however that also seems unlikely.


GRUB is not initialising the video upon boot

I installed Ubuntu 19.04 alongside Windows 10 on my laptop using the "install alongside windows" option.   My problem is that when I boot, grub is there but it doesn't initialise the VGA controller. I can blindly use it by I can selecting a different OS, open a console or anything that is avalaible in grub but I just can't see anything.   However, if before booting on grub go to my BIOS settings and tell it to boot on "ubuntu" (other option is windows boot manager), it does boot on grub and it is visible and works as expected.  the question is: Why doesn't booting without going to the BIOS   not initialise the VGA controller whereas going to the BIOS makes it behave normally?  Things I have already checked :   List item Fast boot and secure boot disabled in BIOS UEFI mode selected Used grub customizer to add a grub theme, which is showing when manually booting on grub I tried to change video driver from NVIDIA to xorg, doesn't change anything I performed a boot repair (reinstalled grub) I changed grub settings from "quiet splash" to "nomodeset" it only made it worse, I could't even boot at all after the invisible grub menu. Ubuntu is set as number 1 in the boot order in the BIOS Tried pressing or holding or smashing Shift or ESC during boot without success


What is $\lim_{x\to\infty}\left(\sin{\frac 1x}+\cos{\frac 1x}\right)^x$?

$$\lim_{x\to\infty}\left(\sin{\frac 1x}+\cos{\frac 1x}\right)^x$$  It is about the $(\to1)^{(\to\infty)}$ situation. Can we find its limit using the formula $\lim_{x\to\infty}(1+\frac 1x)^x=e$? If yes, then how?


Python adding more to a variable then written in the code


Are domains with gTLDs (.ninja, .guru, .museum, etc.) bad for SEO?

Would using one of the newer gTLDs have any adverse effect on SEO?


I am working on large raster in QGIS and I am doing various simulations on them. There is one thing that I don't understand.   I have a large raster (111 072 kb) that I clip to only have the values I'm interested in. The new raster only retains 3% of the values from the original raster. When I look at the values in QGIS, everything seems right. The values that I clipped have the good values and outside it's only a No data area (which is what I want). However, the clipped raster is still pretty heavy for the amount of value it has (85 596 kb), so approximately 77% of the size of the original raster.  Why is the clipped raster still so heavy and not more or less 3% of the original file size?


I know that anything divided by zero is undefined and I understand why. However, I have just discovered this sum, and it confused me greatly. Could anyone explain what is going on here:  $$x-x=0$$ $$x(1-1)=0$$ $$x=\frac{0}{(1-1)}$$ $$x=\frac{0}{0}$$  For example when 'x=3':  $$3-3=0$$ $$3(1-1)=0$$ $$3=\frac{0}{(1-1)}$$ $$3=\frac{0}{0}$$


print lines if comma seperated fields matching together in another line

Input:  1,1,10,1 2,1,10,3 3,0,10,1   Expected Output:  1,1,10,1 2,1,10,3   So how to print lines if field number 2 and 3 repeated in another line.


jQuery .change only works for first instance

I've got a series of conditional select elements that uses .load to insert dynamic content from an external file. The problem is it fires for the first element only and any subsequent instances result in no action.  I started off with this:  jQuery(document).ready(function($) {   $('#autocad-level-1').change(function() {      var cat_id = $(this).val();     console.log('Category Selected');     $('#autocad-level-2-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-2.php?cat_id='+cat_id);  });  $('#autocad-level-2').change(function() {      var p_id = $(this).val();     console.log('Product Selected');     $('#autocad-level-3-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-3.php?p_id='+p_id);  });  });   Research suggested I should use .on as the event handler, but I had no success with that either.  jQuery(document).ready(function($) {  $('#autocad-level-1').on("change", "select", function() {      var cat_id = $(this).val();     console.log('Category Selected');     $('#autocad-level-2-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-2.php?cat_id='+cat_id);  });  $('#autocad-level-2').on("change", "select", function() {      var p_id = $(this).val();     console.log('Product Selected');     $('#autocad-level-3-container').load('http://website.dev/wp-content/themes/dmi/ajax/autocad-level-3.php?p_id='+p_id);  });  });   This is my HTML:
     <select id="autocad-level-1" name="autocad-level-1">       <option value="0">Select</option>       <option value="1">Option 1</option>       <option value="2">Option 2</option>       <option value="3">Option 3</option>       <option value="4">Option 4</option>       ...     </select>

   What am I doing wrong here? I'm out of ideas.


If electron moved in a definite orbit, would that violate Heisenberg uncertainty principle?

If hypothetically a electron does manage to move in a specified orbit (we always find it anywhere on a particular locus), would it break Heisenberg uncertainty principle?


Combinatorial interpretation for the identity $\sum\limits_i\binom{m}{i}\binom{n}{j-i}=\binom{m+n}{j}$?

A known identity of binomial coefficients is that $$ \sum_i\binom{m}{i}\binom{n}{j-i}=\binom{m+n}{j}. $$ Is there a combinatorial proof/explanation of why it holds? Thanks.


Is there a standard place for placing custom Linux scripts?

I am developing a set of scripts, which I want to be present for all users, when I set up a server. But I don't want them in the standard locations like /usr[/local]/[bin],[sbin] etc.  Is there some existing convention for where such scripts should be placed?


Downvoted four times within a minute - serial downvoting?

I checked my rep today and I noticed I was down some points. Somebody has downvoted my question four times within 1 minute:    Is this already serial downvoting? Will it be corrected by a rep-recalculation?


In Eldritch Horror, how do you deal with cases when an event forces you to draw a condition card that you already have?

The rules state that a player cannot choose to take a condition when he already has one of that type.  How do you deal with cases when an event forces you to draw a condition card?  As an example, let's say my character has a debt card and he is asked by an event in the game to draw one. Do you   simply ignore this step in the event resolution flip the card you previously owned and that's it flip the card you previously owned and draw another one (ouch) other?


Can we digest food as well as herbivores

I heard some guy say that we can't digest plant food as well as herbivores. Which seems weird to me seeing as how humans can survive without any nutrient deficiencies besides b12 on only plants but we would pretty much just die of nutrient deficiencies on a carnivore diet. Can someone show me how we can't digest plant food as well as herbivores?


How can I prove that $4^{2n+1}+3^{n+2}$ is always divisible by 13?


I am facing issue with script execution in cron. Same script working fine on terminal and cron under bash version 4.3. But cron is failing for lower bash version.  I want to save command output in file in script like  #!/bin/bash newendcount=$(/bin/cat error_files.log | wc -l) echo $newendcount > /tmp/var.txt   with terminal it is working fine but with cron it not storing line count value, instead giving 0 as result. But same script working properly on terminal.  cronjob is like  * * * * * /bin/bash script.sh > /tmp/output.txt   I editing this question. As I got a solution to my issue. it was because of environment variable mismatch. I have added a line " . /root/.profile " at top of script and now cron is working as expected


I'm making an add-on that uses the websocket library from python. Is there a way to include it in the add-on .zip file? Or do I have to add it to the site packages folder in blenders included python folder?


I am trying to install Wordpress on Lubuntu. I followed the instructions . Including PHP Apache and MySQL setups. Apache and MySQL appear to be running fine.  However, when I go to http://localhost/blog/, I get the following error:     Neither /etc/wordpress/config-localhost.php nor /etc/wordpress/config-localhost.php could be found.   Ensure one of them exists, is readable by the webserver and contains the right password/username.


Is it safe to remove earthing from a scope?

I need to make some differential measurements on a device, but both nodes need to be floating from earth.  I found out the hard way that the negative clip of my oscilloscope voltage probes are connected to the mains earth conductor, but I don't have access to a differential probe.  I was wondering if there is an easy solution to this, and I figured this: inside the scope I have seen that the mains are only connected to a power, old style transformer, while the earth lead is screwed to the metal chassis. Since of course the transformer output is isolated from its input, I think that if I just remove the earth screw from the chassis and isolate the cable I can now connect my device to the scope, avoiding the pesky ground current that destroyed my first board.  The negative terminal I would hook to the probe clip is about 60V over earth, the maximum current it can source is just above 30mA. The input transformer can surely withstand a 60V offset, right?  I think that this is safe because the shell of my scope is all made of plastic, the only metallic parts are the BNC connectors and a couple of blade connectors that I use to calibrate my probes, but they should all be safe.  Is it ok to remove the earth connector from my scope to make such a measurement? I have seen this suggestion all over the web, so I think it must be safe, but I want to ask a board of professionals just to be extra sure.


According to various  something as little as 0.01A = 10mA can be painful, at 0.1A = 100mA you can expierence *   "ventricular fibrillation of the heart". "an uncoordinated twitching of the walls of the heart's ventricles which result in death". "As well as other painful things such as extreme breathing difficulties, Severe Shock, Muscular paralysis ...". *   How is that true? I've worked with an arduino and LEDs, LED Strips etc for quite a while yet never heard that 10mA can be painful let alone 50-100mA deadly.


Are 5e Druids able to transform into Magical Beasts, or are they restricted to ordinary beasts?

so I just wanted to know whether druids could transform into magical beats such as the Winter Wolf in 5e. Me and my friends recently started playing so it would be nice to know. Thanks.


Resource requirements for cloud OpenVPN server

I am building a proxy server for a client of mine. My platform of choice is Amazon EC2 with Arch Linux and Squid running. For the encryption part I have chosen OpenVPN for simplicity and large community size, but unfortunately I do not have substantial experience with it, or with any VPN server for that matter.   The server will be used, at least initially, by 10-15 users. It is expected that at times all 10-15 of them will be connected at the same time.   Now, I think that the generic "Intel Xeon Family" processor listed , along with the 1.7Gb of RAM allocated to the "Small" instance, will be more than enough for the expected number of concurrent connections.  My real concern is network performance. The page linked above uses the words "low", "moderate" and "high" as a metric. Is "low", going to be enough? This really needs to stay a "Small" instance, because the client is pocket-tight. Does anyone know what ¨low¨really translates to?  What options do I have to benchmark the network performance of the instance, even after setting it up? What options are there for benchmarking the network performance of the OpenVPN daemon? I know for sure that the connected clients will not be streaming high B/W content (video and the like) but they will be streaming some real-time data, of the kind that needs to stay real-time.


The question is  Write a method  isMultiple that determines, for a pair of integers , whether  the second integer  is a multiple of the first. The method  should take two integer  arguments  and return true  if the second is a multiple of the first and false  otherwise. [Hint: Use the remainder operator .] Incorporate this method  into an application that inputs a series of pairs of integers  (one pair at a time) and determines whether  the second value  in each pair is a multiple of the first.har()  Here is my code  import java.util.*; public class Multiples {      public static void main(String [] args){          boolean run = true;          while(run = true){         System.out.print("Enter one number:");         Scanner input = new Scanner(System.in);          int num1 = input.nextInt();         int num2 = input.nextInt();          System.out.println("Do you want to enter another pair(y/n)?");         String a = input.next();            boolean result = isMultiple(num1, num2);          if(result = true){             System.out.println(num1 + " is a multiple of " + num2);         }         else{             System.out.println(num1 + " is not a multiple of " + num2);         }          if(YesOrNo(a)){             break;         }           }       }          public static boolean YesOrNo(String a){              if(a == "y")               return false;             else if(a == "n")               return true;             else                 return true;         }           public static boolean isMultiple (int x , int y)         {              if(x % y == 0 || y % x == 0)                  return true;                 else                  return false;          }       }   I want break the while when enter "n" but it is break no matter what I enter.


When i am running my any application it gives this error in androdi studio. please help  null java.lang.NullPointerException     at javax.swing.plaf.basic.BasicComboBoxUI.getMinimumSize(BasicComboBoxUI.java:934)     at javax.swing.plaf.basic.BasicComboBoxUI.getPreferredSize(BasicComboBoxUI.java:911)     at javax.swing.JComponent.getPreferredSize(JComponent.java:1661)     at com.intellij.openapi.ui.FixedSizeButton.getPreferredSize(FixedSizeButton.java:89)     at com.intellij.openapi.ui.FixedSizeButton.getMinimumSize(FixedSizeButton.java:80)     at java.awt.FlowLayout.minimumLayoutSize(FlowLayout.java:463)     at java.awt.Container.minimumSize(Container.java:1840)     at java.awt.Container.getMinimumSize(Container.java:1825)     at javax.swing.JComponent.getMinimumSize(JComponent.java:1745)     at java.awt.BorderLayout.minimumLayoutSize(BorderLayout.java:653)     at java.awt.Container.minimumSize(Container.java:1840)     at java.awt.Container.getMinimumSize(Container.java:1825)     at javax.swing.JComponent.getMinimumSize(JComponent.java:1745)     at com.android.tools.idea.run.AvdComboBox.<init>(AvdComboBox.java:81)     at com.android.tools.idea.run.ExtendedDeviceChooserDialog$2.<init>(ExtendedDeviceChooserDialog.java:92)     at com.android.tools.idea.run.ExtendedDeviceChooserDialog.<init>(ExtendedDeviceChooserDialog.java:92)     at com.android.tools.idea.run.ManualTargetChooser.getTarget(ManualTargetChooser.java:54)     at com.android.tools.idea.run.editor.ShowChooserTarget.showPrompt(ShowChooserTarget.java:97)     at com.android.tools.idea.run.AndroidRunConfigurationBase.getState(AndroidRunConfigurationBase.java:267)     at com.intellij.execution.runners.ExecutionEnvironment.getState(ExecutionEnvironment.java:201)     at com.intellij.execution.runners.BaseProgramRunner.execute(BaseProgramRunner.java:58)     at com.intellij.execution.runners.GenericProgramRunner.execute(GenericProgramRunner.java:31)     at com.intellij.execution.runners.BaseProgramRunner.execute(BaseProgramRunner.java:53)     at com.intellij.execution.runners.GenericProgramRunner.execute(GenericProgramRunner.java:31)     at com.intellij.execution.ProgramRunnerUtil.executeConfiguration(ProgramRunnerUtil.java:94)     at com.intellij.execution.impl.ExecutionManagerImpl.start(ExecutionManagerImpl.java:396)     at com.intellij.execution.impl.ExecutionManagerImpl.access$400(ExecutionManagerImpl.java:61)     at com.intellij.execution.impl.ExecutionManagerImpl$5.run(ExecutionManagerImpl.java:384)     at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)     at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)     at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.run(LaterInvocator.java:332)     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:312)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:745)     at java.awt.EventQueue.access$300(EventQueue.java:103)     at java.awt.EventQueue$3.run(EventQueue.java:706)     at java.awt.EventQueue$3.run(EventQueue.java:704)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:715)     at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:734)     at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:569)     at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:382)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)


If you have a Venezuelan passport, and if you have a Belgium residence permit and are married to a Dutch man, do you need a transit visa when you change planes in London on your return trip to Amsterdam? UK border check will be done in between flights.  If I check the government site, I think it is not necessary because of the Belgium residence permit. Am I right? It's not all clear to me.


If electromagnetic waves have magnetic fields, why beam of flashlight is not disrupted by a Magnet?

Wikipedia article about Electromagnetic Radiation says "As an electromagnetic wave, it has both electric and magnetic field components". And  also confirms Light is EM wave.  Since we know that light travels through electromagnetic waves. Does that mean when we hold a Magnet close to the beam of a flashlight, it should interact with the waves and cause funny things to happen ?


Where does the idiom "beating around the bush" come from?


Is there a function so that $f(f(x))=1/x$?

I tried to look for a function that fulfills this rule; $$f(f(x))=\frac{1}{x}$$  I tried a lot, and I didn't find anything.  Can anyone help me find such a function? Or prove that there isn't? It doesn't have to be a real function.


Where can I ask this question about "Chrome indexedDB"?

Where can I ask this question about Chrome-IndexedDB?     I have a disk space issue and see that IndexedDB of Chrome has 20GB.   How can I limit the size of IndexedDB?


How do I tell winetricks to work with a different prefix?

I'm trying to enable alsa on different prefix than default through winetricks.  More specifically, the prefix that has Rosetta Stone on it, as it cannot see my microphone.  When I open winetricks, it only lets me select default.  I tried anyway, on default, and it did not resolve the issue.  I saw some answers online, through the terminal, but that didn't work either.  Maybe I have the syntax wrong?  steve@stevelap:~$ WINEPREFIX=~/.PlayOnLinux/wineprefix/Rosetta sh winetricks alsa sh: 0: Can't open winetricks steve@stevelap:~$ sudo WINEPREFIX=~/.PlayOnLinux/wineprefix/Rosetta sh winetricks alsa [sudo] password for steve:  sh: 0: Can't open winetricks   Could anyone please offer assistance?  Thanks!


How to reset a Live Ubuntu 12.04 Usb so that I install tails instead

I currently have a Live USB with Ubuntu 12.04 on it and my Laptop is a Windows 10 machine.  I would like to remove Ubuntu 12.04 and use Tails instead. The reason I want to use Tails is that I am planning on storing my Cryptocurrency Wallets on Tails and tails is recommended for this due it having Electrum.   If Tails is not necessary for this can you please let me know how I can upgrade to the latest version of Ubuntu safely without damaging my Windows 10 OS.  Thank you


Show that the orders of $x$ and $axa^{−1}$ of a group are equal

Let $(G, ·)$ be a group, and let $a, x$ ∈ $G$. Show that the orders of $x$ and   $axa^{−1}$ are equal.   My attempt:  In order to show that the orders of $x$ and $axa^{−1}$ are equal, I have to show that $axa^{−1}$ = $x$.   Since $G$ is a group, we have that $axa^{−1}$ = $a.(x.a^{-1}) = (a.x).a^{-1}$ (associativity) = $a^{-1}.(a.x)$ (commutativity) = $(a^{-1}.a).x$ (associativity) = $e.x = x.e = x$ (property of the identity element).  Hence, I've shown that $axa^{−1}$ = $x$, and so their orders are equal.  Is my proof correct? Did I make a mistake somewhere? Do you have other suggestions?


Taking non-connecting flight from Dubai (DXB)

I am currently studying in Canada since a year. I am planning to travel to Karachi, Pakistan in the mid of Dec 2015. Since connecting flights were quite expensive in that peak time, so I booked two non-connecting flight that first takes me from Calgary to Dubai, the other from Dubai to Karachi.  The confusion is I don't have visa for Dubai, so am I still able to use Dubai as transit route to take my another flight to Karachi and return back via same route?  Your response will be highly appreciated.  Thanks


Hashing function as a cipher in CTR mode

Can we use hashing function in CTR mode as a cipher? And our key could be a random initialization vector. Are there any practical problems with that idea, that we don't do this?


Is it correct to say:     1) I've lived in London for five years.   Or      2) I've been living in London for five years.   I think second one is correct because we use present perfect continuous for actions started in past and is continuing in present.


Would it be useful to be able to vote for Canonical answers?

I've added  to consider the possibility of categorizing up to one answer per question as Canonical — i.e. worthy of being considered the consensus complete and accurate answer. A Canonical answer would have to include a link to an authoritative source, and at least 50% of voters would need to approve of it (as opposed to another answer to the same question or a "no possible canonical answer" option).  It's probable that many, if not most, questions would never have a Canonical answer. However, when one is possible and is provided, it should be a little more golden, and making it easier to find would be valuable for searching the site.


"She lay the gift basket on the coffee table" is correct.  Would "She laid the gift basket on the coffee table" be correct? Or do we need to have the word "had" before "laid," as in "She HAD laid the gift basket on the coffee table"?


I find people asserting that Stack Exchange is paid for by advertising revenue.  In the course of almost four years of posting on Stack Exchange almost daily and amassing a reputation of more than 100,000, I don't recall ever seeing anything that looked like a paid advertisement.  I don't fail to notice them on Facebook and Google.  Is it really subtle subliminal stuff?  Where is it found?


How do you move an NPC's housing flag in Terraria?


How to compute the gradient of a quadratic form?

Let scalar field $f : \mathbb{R}^n \to \mathbb{R}$ be given by $$f(x) = x^TA^TAx - \lambda( x^T x - 1)$$ where $A$ is an $n \times n$ matrix and $\lambda$ is a scalar. How to compute the gradient $\nabla f$? I know that it would be the Jacobian matrix (or gradient), but is there a faster way to compute it rather than writing out everything in terms of components and taking partial derivatives? The reason I ask is my classmate, when we considered this function in class, was able to compute the derivative as $A^T A x - \lambda x$ rather quickly.


What does this mean? "Your UK visa application has been issued"

Your UK visa application has been issued.      PLEASE DO NOT GO TO THE VISA APPLICATION CENTRE BEFORE THEY CONTACT YOU.      You will be contacted by the Visa Application Centre when your documents are ready for collection, or have been dispatched via courier where this is relevant.       You are reminded that you should avoid making travel plans until you have collected your passport, as the outcome of your visa application is not final until you receive your passport.      Please ensure you check the details on your visa when collecting your passport. If you need to contact us you can do so via our International Enquiry Service at www.gov.uk/contact-ukvi-outside-uk      Kind regards,      UK Visas and Immigration   British Embassy Abu Dhabi     Your UK visa application has been issued.   I know words like processed, forwarded, received, refused but never heard anything like that, so I am confused.


I'm making a tabular and I'd like to automatically do a like break rather than going beyond the page.   This is my tabular code:  \begin{table}[h] \begin{tabular}{|l|l|l|} Use Case Navn:          & \multicolumn{2}{l}{Opret Server} \\ Scenarie:               & \multicolumn{2}{l}{At oprette en server med bestemte regler som tillader folk at spille sammen. More Text more text More Text} \\ \end{tabular} \end{table}   This is my preamble:  \documentclass[danish,a4paper,twoside,11pt]{report} \usepackage{babel} \usepackage[utf8x]{inputenc} \usepackage{natbib} \usepackage{graphicx} \usepackage{epstopdf} \usepackage{titling} \usepackage{color} \usepackage{xcolor} \usepackage{nag} \usepackage{tabularx}  \newcommand{\myparagraph}[1]{\paragraph{#1}\mbox{}\\}   This is how it looks right now:


my side by side table overlap, and I can't manage to adjust their sizes. Any suggestion is highly appreciated!    \documentclass{article} \usepackage{array}  \begin{document} \begin{table}[htbp] \caption{filter window size} \label{tab:config_filternum} \begin{minipage}{.4\textwidth}     \begin{tabular}{| m{3cm} | m{4.3cm} | c |}   \hline  number of entity filter (size 1) & number of context filters (size 2, size 3,  size 4) & Accuracy\\ [2ex]   \hline     32  &  32  ,  32  ,  32  &  0.835 \\[0.5ex]     \hline     32  &  64  ,  64  ,  64  &  0.821 \\[0.5ex]     \hline     \hline  \end{tabular} \end{minipage}% \quad \begin{minipage}{.4\textwidth}     \begin{tabular}{| m{3cm} | m{4.3cm} | c |}   \hline  number of entity filter (size 1) & number of context filters (size 2, size 3,  size4) & Accuracy\\ [2ex]   \hline 512  &  32  ,  32  ,  32  &  0.910 \\[0.5ex] \hline 512  &  64  ,  64  ,  64  &  0.922 \\[0.5ex] \hline \hline \end{tabular} \end{minipage} \end{table}   \end{document}


How to install wkhtmltopdf on Ubuntu 16.04 (armhf)

I'm trying to install  on my Ubuntu 16.04  server. I've found  tutorial online on how to install it. The problem is I'm stuck at step 3:    I'm getting the following error:  sudo dpkg -i wkhtmltox-0.12.2.1_linux-trusty-amd64.deb dpkg: error processing archive wkhtmltox-0.12.2.1_linux-trusty-amd64.deb (-- install): package architecture (amd64) does not match system (armhf) Errors were encountered while processing: wkhtmltox-0.12.2.1_linux-trusty-amd64.deb   Anybody can help me install this?