What's the difference between poweroff and halt?
What is the difference between Halt and Shutdown commands?
Can anyone please tell me whether the following function $d:\mathbb{R}^2 \times \mathbb{R}^2 \to  \mathbb{R}$ is really a metric or not on $\mathbb{R}^2$.  $$ d((x_1,x_2),(y_1,y_2))= \begin{cases} |x_1-y_1|, &amp;\text{ if } x_2=y_2\\ |x_1|+|y_1|+|x_2-y_2|, &amp;\text{ if } x_2 \neq y_2. \end{cases} $$  If it really is indeed a metric, please give the proof of triangle inequality.(I'm OK with the other two conditions). Why does Google Analytics report 100% bounce rate when the page has lots of page views? Google Analytics reports 100% bounce rate for a page which has lots of page views and an Avg Time on Page of 32 seconds. Shouldn't one of the following be true?  Either the bounce rate is less than 100% when the Avg Time on Page is greater than 0 or the Avg Time on Page is 0 when the bounce rate is 100%.  I fail to see how or why the report does not conform the above two conditions. When —the bartender at the Cantina at Mos Eisley spaceport in the first Star Wars—says:     “We don’t serve their kind here.”   In reference to C-3PO and R2-D2 entering the bar, it’s certainly a bit prejudicial, but are these commonly held views in this universe? We don’t see it happen anywhere else in the films but is it implied elsewhere? Cat 5/6 in same conduit as power: is NM-B required, or is THHN acceptable? Batch files: How to read a file? Firstly, this is a homework problem so please do not just give an answer away. Hints and suggestions are really all I'm looking for.  I must prove the following using mathematical induction:     For all $n\in\mathbb{Z^+}$, $1+2+2^2+2^3+\cdots+2^n=2^{n+1}-1$.   This is what I have in my proof so far:     Proof: Let $p\left(n\right)$ be $\sum_{j=0}^n 2^j=1+2+2^2+\cdots+2^n=2^{n+1}-1$. Then $P\left(0\right)$ is    \begin{align} \sum\limits_{j=0}^0 2^j=1=2^1-1.\tag{1} \end{align} Hence    $P\left(0\right)$ is true. Next, for some $k\in\mathbb{Z^+}$, assume    $P\left(k\right)$ is true. Then \begin{align}  \sum\limits_{j=0}^{k+1}2^j&amp;=\left(\sum\limits_{j=0}^k  2^j\right)+2^{k+1}\tag{2}\\ &amp;=2^{k+1}-1+2^{k+1}\tag{3} \\ &amp;=2\cdot 2^{k+1}-1\tag{4}\\ &amp;=2^{k+2}-1\tag{5}\\ &amp;=2^{\left(k+1\right)+1}-1.\tag{6} \end{align}   Therefore, $P\left(n\right)$ holds for all $n$.$\;\;\;\;\blacksquare$   Is everything right? My professor went over the methodology in class quite fast (and I had a bit too much coffee that night) and I want to make sure I have it down for tomorrow night's exam. Let $m$ and $n$ be two integers. Prove that if $m^2 + n^2$ is divisible by $4$, then both $m$ and $n$ are even numbers.   I think I have to use the contrapositive to solve this. So I assume $\neg P\implies Q$ and I have to derive $\neg Q$? I know its easier to show odd numbers rather than even... but im still unsure how to do this practice problem. I would like to use client-side Javascript to perform a DNS lookup (hostname to IP address) as seen from the client's computer. Is that possible? Is it possible to get rid of the bullets in the miniframes outer theme Bit error rate calculation for LIN protocol I am having this microcontroller -   I am using an 8MHz external clock. I want to calculate the Bit error rate of my LIN Communication. My LIN Communication Baud rate is 19.2kbps. My questions :  Can I use the LPUART Module in the Mirocontroller for the LIN Communication?  How to find the Bit error rate for the LIN Protocol communication for my baud rate of 19.2kbps and external clock of 8MHz.   I found this below from the reference manual. But not sure, how to calculate the Bit error rate from this.   How to calculate the SBR Register value, OSR and the LPUART ASYNCH Module clock?  Please help Say you have the infinitely continued fraction: $$x+\cfrac{1}{x^2+\cfrac{1}{x^3+\cfrac{1}{x^4+\ddots}}}$$ When $x=1$, you can see that it's $$1+\cfrac{1}{1+\cfrac{1}{1+\cfrac{1}{1+\ddots}}}$$ which converges upon the golden ratio $\phi = 1.61803398875...$. What if I were to plug in $x=2$? $$2+\cfrac{1}{4+\cfrac{1}{8+\cfrac{1}{16+\ddots}}}$$ Using a caluclator, it seems to converge upon the irrational number: $2.24248109286...$ Is there any way I can represent this irrational number algebraically? Resolving heteroscedasticity in Poisson GLMM How to import a .max model into Blender? I've tried to import but I don't see the (.max) file as an option when importing. Is there another way to import the 3DMax model into Blender for rigging and animation? how to run the dialog command with proccess Please look on my code – ( bash script )  I want to display both dialogs on the screen on the same time,   one dialog display the:  tail –f from - /var/log/proccess1.log  ,   and the second dialog display the:  tail –f from the file - /var/log/proccess2.log     but the sad fact is that I can display only one dialog and not both dialogs ( because when I run the first dialog , the second dialog will activate only if the first dialog will killed )   So I create process on the second dialog ( ….. ) &amp;    , in order to display both dialogs    But …. the second dialog create process number but not create the second dialog GUI , ( seems that when we create dialog with process , the process not send the dialog to standard output )  So how to  run the second dialog with process but send the dialog GUI to screen ? , or other solution in order to display both dialogs on screen  My code       #!/bin/bash       # this dialog will locate the tail box on the top of the screen      dialog --begin 15 10  --tailbox   /var/log/proccess1.log  13 125         # this dialog will locate the tail box down in the screen      ( dialog --begin 37 10  --tailbox   /var/log/proccess2.log    13 125 ) &amp; Why is an untranslated string not showing up? In my module I have some custom strings. I use these in the t() function. When I go to admin/config/regional/translate/translate and filter the untranslated strings my custom strings do not show here.  What could be going wrong? Solving a six-degree polynomial of the form $ax^6+bx^3+g$. I read that it is not always possible to solve but from Wikipedia:      Some sixth degree equations, such as $ax^6 + dx^3 + g = 0$, can be solved   by factorizing into radicals, but other sextics cannot.   So how do you solve this? I've stumbled upon this equation where; $a = n^2$, $d=m^2n-2p^2$, and $g=m^4$. Where the $a,d,g$ corresponds to the above mentioned sextic-equation and $m,n,p$ are input variables. I apologize for that ton of variables in use, might cause some confusion. Is this possible using Galois Theory or by any other means? utf8 and ISO 8859-1 encoding references trouble I have to use one particular template ( am obliged to use it for my thesis) it uses \bibliographystyle{plain} Ihave both english and frensh text on it (for abstract and résumé) there is no problem for characters like ( é, ç...) but some of references does not appear they are replaced by [?] knowing that foe encoding \RequirePackage[latin1]{inputenc} how to fix this problem please!   \documentclass{article}   \RequirePackage[latin1]{inputenc}   \RequirePackage{fancyhdr}     blabla \cite{nayak2015comprehensive, byun2002applications, shah2004sequential, fletcher2009support, cornuejols2011apprentissage, byun2002applications}   @article{nayak2015comprehensive,    title={A comprehensive survey on support vector machine in data mining     tasks: applications \&amp; challenges},    author={Nayak, Janmenjoy and Naik, Bighnaraj and Behera, HS},    journal={International Journal of Database Theory and Application},    volume={8},    number={1},    pages={169--186},    year={2015}    }      @inproceedings{shah2004sequential,     title={Sequential k-nearest neighbor pattern recognition for usable      speech classification},     author={Shah, Jashmin K and Smolenski, Brett Y and Yantorno, Robert E      and Iyer, Ananth N},     booktitle={Signal Processing Conference, 2004 12th European},     pages={741--744},     year={2004},     organization={IEEE}     }      @misc{fletcher2009support,      title  = {Support vector machines explained},     author = {Fletcher, Tristan},     journal= {University College London, London},     year   = {2009},     howpublished = "\url{http://sutikno.blog.undip.ac.id/files/2011/11/SVM-     Explained.pdf}",     note   = {Accessed: 2017-04-30}     }      @inbook{cornuejols2011apprentissage,      title={Apprentissage artificiel: concepts et algorithmes},      author={Cornu{\'e}jols, Antoine and Miclet, Laurent},      year={2011},      pages={279--309},      publisher={Editions Eyrolles}       }      @incollection{byun2002applications,      title={Applications of support vector machines for pattern recognition:       A survey},      author={Byun, Hyeran and Lee, Seong-Whan},      booktitle={Pattern recognition with support vector machines},       pages={213--236},      year={2002},      publisher={Springer}      }    \end{document}  knowing that my references work well on other template but this one no how to fix this problm please! here is the error I got   Edited here is the link to the template  in fact I have created a littele example ( since I could not publish my thesis ...) the error has disappeared but my references still [?] Undergraduate classical mechanics introduces both Lagrangians and Hamiltonians, while undergrad quantum mechanics seems to only use the Hamiltonian. But particle physics, and more generally quantum field theory seem to only use the Lagrangian, e.g. you hear about the Klein-Gordon Lagrangian, Dirac Lagrangian, Standard Model Lagrangian and so on. Why is there a mismatch here? Why does it seem like only Hamiltonians are used in undergraduate quantum mechanics, but only Lagrangians are used in quantum field theory? Why didn't the Emperor realize that torturing Luke to death in front of Vader might be a bad idea? I'm using the following syntax for my code snippets  \begin{minipage}{\textwidth} \begin{lstlisting}[caption=&lt;something&gt;, label=&lt;something&gt;] The REST Endpoint URL     is http://api.flickr.com/services/rest/  To request the flickr.test.echo service,     invoke like this:    http://api.flickr.com/services/rest/       ?method=flickr.test.echo&amp;name=value  By default, REST requests will send a REST response. \end{lstlisting} \end{minipage}   and I would like to have  \begin{code}[&lt;caption&gt;, &lt;label&gt;] ... code ... \end{code}   which would behave exactly the same.   So I tried this thing but it won't compile and I can't spot the problem  \newenvironment{code}[2][]%     {         \minipage{\textwidth}          \lstset{             basicstyle=\ttfamily,             breaklines=true,             captionpos=b,             frame=bottomline,             extendedchars=true         }         \begin{lstlisting}[caption=#1, label=#2]     }     {         \end{lstlisting}         \endminipage     }   Error when running pdflatex  ! Package inputenc Error: Unicode char \u8:�\expandafter not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help.