unsupported operand type(s) for /: 'str' and 'int'
How can I read inputs as numbers?
I would like to declare functions in tikz for multiple uses of the same function within the code.  Sadly, it seems that the tikz "declare function" is not compatible with the french option in babel. Indeed, the following code (that I simplifed on purpose) runs fine :  \documentclass[english]{article} \usepackage{babel}                       \usepackage{tikz}  \begin{document} \begin{tikzpicture}     \tikzset{declare function={Carre(\t)=\t*\t;}}     \draw plot [domain=-1:1] (\x,{Carre(\x)}); \end{tikzpicture} \end{document}   But when I replace   \documentclass[english]{article}   with   \documentclass[english,french]{article}   compilation generates an error. This is what the log file says :     Missing character: There is no = in font nullfont!   Missing character: There is no @ in font nullfont!   Missing character: There is no @ in font nullfont!      Runaway argument?   -1:1] (\x ,{Carre(\x )}); \end {tikzpicture} \end {document}    ! Paragraph ended before \pgfmath@local@@functions was complete.                          \par    l.18       I suspect you've forgotten a `}', causing me to apply this   control sequence to too much text. How can we recover?   My plan is to forget the whole thing and hope for the best.   Before posting this, I updated all packages without success.  Any help welcome! How to get the last date of a particular month with JodaTime? Is $K[a,b]=K(a,b)$ for algebraic $a, b$? Rather than rephrasing my question, let me describe to you the desired user-case:  I create a short shell-script to run command "gnome-terminal --someoptionflagname 'my text to be posted'", and execute this script.  Gnome-terminal pops up, with command-line prompt followed by my text.   ie: fields@mycomputer:/$ my text to be posted  Can this be done? Where exactly does energy quantisation come in for light? Planck quantised the energy of light in order to solve the black body radiation problem. However, I am confused as to exactly what he quantised. On one hand, I have seen that he quantised the energy of oscillators in the black body (source below).     However, the second version of the story I've heard is that it is simply that light energy is given off in discrete chunks (where every photon itself can have any value of energy it likes depending on frequency and is not quantised).   To me, the first idea doesn't make sense because $E=hf$ and as $f$ can be any real number that means the energy of each photon can be any real number. I would believe the second version, however I don't understand how this version of quantisation leads to reducing the number of high frequency waves emitted and thus solving the UV catastrophe. Could you please explain exactly how releasing energy in chunks (of arbitrary size themselves) means less will be released in the higher frequencies? How to make child process die after parent exits? Response.Redirect to new window I want to do a Response.Redirect("MyPage.aspx") but have it open in a new browser window. I've done this before without using the JavaScript register script method. I just can't remember how? When I upload an image to Stack Overflow, I cannot see my JPEG file in my post. It's all blank. I've tried it with different files, but gotten the same result. How slow are .NET exceptions? I don't want a discussion about when to and not to throw exceptions. I wish to resolve a simple issue. 99% of the time the argument for not throwing exceptions revolves around them being slow while the other side claims (with benchmark test) that the speed is not the issue. I've read numerous blogs, articles, and posts pertaining one side or the other. So which is it?  Some links from the answers: , , . Where can I find a list of all the Stack Exchange sites?  I need to ask a question about cars (where my total knowledge is about zero) but I can't find a cars Stack Exchange site - tried guessing all the obvious (and pun based) names.  I assume the list of a dozen or so at the bottom of this page is only a subset? There must be a site on a topic as geeky as cars!  A list of future/beta sites would also be useful - I found a few on topics I'm interested in only after they had been up for a while. \nameref breaks for star versions of section/paragraph when titlesec is loaded \nameref breaks for the star versions of section, paragraph when titlesec is loaded. I have a document that numbers paragraphs by default, but I have a few I do not want to number but would like to refer to. These are marked with \paragraph*, however, if the titlesec package is loaded at the same time, it causes nameref to display an empty string (the link box of hyperref is still visible).  MWE:  \documentclass[12pt]{article} \usepackage[sf]{titlesec} %comment this out and it works fine. \usepackage{hyperref} \begin{document} \section{Sections} \label{sec} This is \nameref{sec} \paragraph{A named Paragraph} \label{par} This is \nameref{par} \paragraph*{A starred named Paragraph} \label{par:star} This is \nameref{par:star} \end{document}   I suspect titlesec causes this defect for ALL star variants of sectioning commands but have not tested this. For me only paragraph* is relevant however a fix for all variants would be the best.  I have a hunch it might be related to this:  however this happens to go way beyond my latex knowledge and is just "magic" for me. I'm trying to include a link to some code on OneDrive; the link includes an underscore, which is causing a lot of trouble.  I tried adding the entry like this:  @misc{code,     title = {Code},     url = {https://1drv.ms/link_link} }   I use \usepackage{url} and \bibliographystyle{IEEEtran}. Everything compiles fine and the bibliography shows the correct entry. However, if you click the link, it opens a page at https://1drv.ms/link - so ignoring the underscore and everything after it, which leads to a wrong page. Even copy and paste from the PDF doesn't work since the underscore is copied as space, which again is a broken link.  How can I add the link such that it can be clicked and copied properly? I tried \_, \usepackage{underscore}, {{link}}, different bibtex entries but nothing worked. Also all the related questions/answers don't answer mine. Is the cube root of a prime number rational? Keyboard layout indicator sometimes disappears Ubuntu 18.04.1 after some update Can a dichotomous variable (yes/no) be merged with a Likert measure (1,2,3,4) using z scores? A (probably trivial) induction problem: $\sum_2^nk^{-2}\lt1$ HTTP GET request in JavaScript? I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget. Prove by induction that $n! > 2^n$ Suppose that when $n=k$  $(k\geq4)$, we have that $k!&gt;2^k$.  Now, we have to prove that $(k+1)!\geq2^{k+1}$ when $n=(k+1)$ $(k\geq4)$.  $$(k+1)! = (k+1)k! &gt; (k+1)2^k  \text{ (since }k!&gt;2^k)$$  That implies $(k+1)!&gt;2^k2$, since $(k+1)&gt;2$ because of $k$ is greater than or equal to 4.  Therefore $(k+1)!&gt;2^{k+1}$  Finally  we may conclude that $n!&gt;2^n$ for all integers $n\geq4$    Solved, thank you! How to recover deleted files? Remove Personal Options section from Profile I want to hide/remove the Personal Options in the Your Profile (wp-admin/profile.php) admin page.  I am aware that solutions for this exist, but I they use jQuery to do hide this section. This works, but when a user has JavaScript disabled in their browser, it will show up again. Therefore it is not a proper way to remove Personal Options.  Is there a way to remove the Personal Options section from the HTML source of the page? This means no jQuery or CSS hacks, or core file modification.