Updating from 19.04 to 20.10
Can I skip over releases when upgrading?
Inequality involving sides of a triangle How can one show that for triangles of sides $a,b,c$ that   $$\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b} &lt; 2$$  My proof is long winded, which is why I am posting the problem here.   Step 1: let $a=x+y$, $b=y+z$, $c=x+z$, and let $x+y+z=1$ to get   $\frac{1-x}{1+x}+\frac{1-y}{1+y}+\frac{1-z}{1+z}&lt;2$  Step 2: consider the function $f(x)=\frac{1-x}{1+x}$, and note that it is convex on the interval (0,1), so the minimum of   $\frac{1-x}{1+x}+\frac{1-y}{1+y}+\frac{1-z}{1+z}$  is reached when the function takes the extreme points. i.e. $x=y=0, z=1$.    But going back to the fact that this is a triangle, we note that $x=y=0 \implies a=0$ which is not possible, so the inequality is strict. Why did Voldemort hide two Horcruxes in Hogwarts? What is the easiest way to strip a desktop edition to a server edition? We have installed Ubuntu desktop edition on our development server. Now that we have it in a data center we would like to strip it down to a server edition.  Is there an easy way of doing so rather than just going in and uninstalling packages by hand? Do PhD courses in engineering fields in European non-English speaking countries require knowledge of the native language? Can a Ph.D. student who only knows how to speak English study in a European non-English speaking country (e.g., Austria, Netherlands, Switzerland, Italy, etc.)  without any problems? Does applying to these universities require knowledge of that country's language? Solutions to the equation $ze^{a-z}=1$ Let $a \in \mathbb{R}, a&gt;1,$ and consider the equation $$ze^{a-z}=1$$ How many solutions does this equation have in the unit disk, and how many of those solutions are real?   My attempt to solve was to use the Argument Principle on the function $f(z)=ze^{a-z}-1$, in hopes of recovering the number of zeroes that way. The integral I attempted to compute for this was $$\int_{|z|=1} \frac{e^{a-z}-ze^{a-z}}{ze^{a-z}-1}dz=\int_{|z|=1}\frac{1-z}{z-e^{z-a}}dz$$  I do not know how to proceed from here, as the $e^{z-a}$ in the denominator seems problematic. Thanks for your help! Can I play against or with Xbox 360 players through my Xbox One? Is it possible to play against and with Xbox 360 players through my Xbox One? Why is empty set an open set? I thought about it for a long time, but I can't come up some good ideas. I think that empty set has no elements,how to use the definition of an open set to prove the proposition. The definition of an open set: a set S in n-dimensional space is called open if all its points are interior points. Unit testing is, roughly speaking, testing bits of your code in isolation with test code. The immediate advantages that come to mind are:  Running the tests becomes automate-able and repeatable You can test at a much more granular level than point-and-click testing via a GUI    My question is, what are the current &quot;best practices&quot; in terms of tools as well as when and where to use unit testing as part of your daily coding? Lets try to be somewhat language agnostic and cover all the bases. Finding centrelines from polygons in QGIS? I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file. Undefined variable problem with PHP function While attempting to delete a question which was answered by myself, and with no other answers, I got the following warning:     Delete this answered question?      We do not recommend deleting questions with answers because doing so   deprives future readers of this knowledge.      Repeated deletion of answered questions can result in your account   being blocked from asking. Are you sure you wish to delete?   I understand that deleting your question when someone else has answered it is effectively nullifying the effort that person put into that answer, which is bad. But is it bad if the only answer that's deleted along with your question is your own? I understand there has been so much on this topic but I am still confused. I get that if the person is the subject it is who and anything else is whom. However, I'm really struggling to work out this rule for the following sentence:     The scope of which his account of morality applies to is therefore restricted to those whom/who the ‘notion of justification to a being of that kind makes sense.’   Should it be who or whom? I can't work out the subject and object. Fast way of finding lines in one file that are not in another? Rename ToC, List of Figures, References I would like to know how to rename the standard list of figures, table of contents, and references. What I saw so far relying on \renewcommand{\contentsname}{name} did not work so far.  Here's the list of preambles I use:  \documentclass[12pt]{report} \usepackage[utf8]{inputenc}  \usepackage{fourier} \pagestyle{headings} \usepackage{marvosym} \usepackage[pdftex]{graphicx} \usepackage[margin=2.5cm]{geometry} \usepackage{rotating} \usepackage{amsmath} \usepackage{booktabs} \usepackage{url} \usepackage{natbib} \usepackage{setspace} \linespread{1.5} \newenvironment{remark}{\par\mbox{}\par\noindent{\bfseries             \emph{Remark}\/}:\normalfont}{\par} \newenvironment{defin}{\par\mbox{}\par\noindent\bfseries \emph{\Pointinghand\     }\normalfont}{\par} \setcounter{toc**strong text**depth}{2}  \usepackage[colorlinks=true, a4paper=true, pdfstartview=FitV, linkcolor=blue, citecolor=blue, urlcolor=blue]{hyperref} \pdfcompresslevel=9 \setstretch{1.0} %vertical stretch \usepackage{fontspec} \setmainfont[BoldFont       = AvenirNextRoundedPro-Bold.otf , ItalicFont     =AvenirNextRoundedPro-Italic.otf]{AvenirNextRoundedPro-Reg.otf} \defaultfontfeatures{Mapping=tex-text} \usepackage{multirow} \usepackage{array} \usepackage{booktabs} \usepackage{hyperref} \hypersetup{ hidelinks, } \usepackage{ragged2e} \usepackage{euler} \usepackage[euler-digits,euler-hat-accent]{eulervm} \usepackage[labelfont=bf]{caption} \usepackage{wrapfig} \usepackage{amsmath} \usepackage{amssymb}  \usepackage[english]{babel} \usepackage[nottoc]{tocbibind} %Adds "References" to toc \usepackage{titlesec} \titleformat{\chapter}[display]{\bfseries\huge}{\filleft\Large\chaptertitlename~\thechapter}{1ex}{\vspace{1ex}\filright}[\vspace{0.5ex}\titlerule] \usepackage{float} \usepackage{etoolbox} \makeatletter \patchcmd{\@caption}{\csname the#1\endcsname}{\csname fnum@#1\endcsname:}{}{} \renewcommand*\l@figure{\@dottedtocline{1}{2em}{6em}} \let\l@table\l@figure  \makeatother % default for 3rd arg: 2.3em - for list of figures and tables \usepackage{background} \definecolor{textcolor}{HTML}{000000}             \newcommand\Text{c\quad o\quad n\quad f\quad i\quad d\quad e\quad n\quad t\quad i\quad a\quad l} \SetBgColor{textcolor}\SetBgOpacity{0.3}\SetBgAngle{90}         \SetBgPosition{current page.center} \SetBgVshift{-0.33\textwidth} \SetBgScale{1.8}         \SetBgContents{\sffamily\Text} %for confidential   I also use TexMaker. I do not know how relevant it is, but here my document language is set to English (even if it's not the language I write in, in that document, but it isn't a problem seemingly). What I also saw is that, if I remove babel and the references, I can rename my ToC and LoF, LoT. But I need the references though. Any tip would be very welcome!  Edit: I cannot provide text data from my project, because it is confidential. Here's what I can provide from the main document. Here is what I can include more.  \begin{document} \include{02_front}  \setcounter{page}{0} \pagenumbering{roman} \tableofcontents \listoffigures \listoftables \newpage \setcounter{page}{0} \pagenumbering{arabic} \chapter{blabla} \section{test é è åøæ î} \appendix \bibliographystyle{plain}  \bibliography{80_refs}   \end{document}   Also, I actually finished writing my thesis but I need to summarize it briefly in another language, am would be extremely unwilling to test and remove packages that "might be" not very useful. I literally only have to change these names of ToC, LoF, ToF and references. What is the difference between UNION and UNION ALL? When should I upgrade my camera body? As the question says, when should I upgrade my camera body? In particular, if I have a low- to mid-range body (A DSLR such as a Nikon D3200 or Nikon D5100, or Canon SL1 or T5, or a mirrorless camera such as a Panasonic GH3 or an Olympus E-PL6). How do I know when I need to upgrade?  I have a complement of "kit" lenses, such as an 18-55mm f3.5-5.6 and a 55-200mm f4-5.6. Maybe I've even added a 50mm 1.8 to the kit. Flash is only for indoors (right?) and I usually shoot outside, so that means I don't need an external flash.  I shoot photos of my family and friends whether out at the park or having a picnic, my kids sports practices and games, vacation photos, as well as some landscapes, flowers, and whatever else catches my eye. Pretty familiar territory. I'm not a professional and don't intend to become one. How to obtain $f(x)$, if it is known that $f(f(x))=x^2+x$? Make bash exit != 0 when called by AWK and interrupted with ^C I'm having an issue with the following piece of (G)AWK script:  do {     ... } while (system("sleep 10"))   My intention is to break the loop when the user presses ^C during the sleep, but it's not working.  I believe the problem is that Bash exits with 0 when interrupted with ^C, at least when it's executed by AWK's system():  $ awk 'BEGIN { print "\n" system("sleep 2") }' (let the sleep complete) 0      $ awk 'BEGIN { print "\n" system("sleep 2") }' ^C 0   Why is it so?   Is this a bug in Bash or in (G)AWK?  Is there a simple solution that doesn't involve complicated Bash-specific syntax like trap?  The best I could come up with is this:  do {     ... } while (42 == system("sleep 10 &amp;&amp; exit 42"))   which still looks like a kludge to me. What is the difference between standard i386 download and the amd64 download of Ubuntu 11.04? I am currently running the i386 on an amd machine, would my system work better with the amd64 download instead? (my machine was running Windows 7 64bit, but I neglected to look at that prior to installing Ubuntu). How do I check whether a module is installed in Python, and install it if needed? In terminal, after I start Python, how will I know what are the modules present in python? Suppose I need to learn the modules NumPy and SciPy.   How will I install it if it is not installed?  How will I know if it is already installed?