Using quotes inside sageplot environment in SageTeX

Question

Here's the question: how do I get the following to work in SageTeX? The quotes always lead to an error.

\sageplot{plot(cos(x),(x,0,pi),label='$\cos(x)$')}

Double quotes, escaping them, ... nothing seems to work.

Answer 1

I don't know enough to tell you what's going on, but this works:

\documentclass{article}
\usepackage{sagetex}
\begin{document}
\pagestyle{empty}
\begin{sagesilent}
G=Graphics()
var('x')
G+=plot(cos(x),(x,0,pi),label='$\cos(x)$')
\end{sagesilent}
\[ \sageplot{G}\] 
\end{document}

Note, to get even more control over the placement of your text label try this:

\documentclass{article}
\usepackage{sagetex}
\begin{document}
\pagestyle{empty}
\begin{sagesilent}
G=Graphics()
H=Graphics()
var('x')
G+=plot(cos(x),(x,0,pi))
H+= text("$\cos(x)$", (3, 1), fontsize=16, color='black')
\end{sagesilent}
\[ \sageplot{G+H}\] 
\end{document}

The people at AskSage will know what's best. Here's output from the first set of code:

Answer 2

It's not the quotes that are the problem here. If you used 'cos(x)', it will work. The real problem is the dollar signs and the \cos: TeX is interpreting stuff before \sageplot. With the dollar signs, here's what ends up in your .sagetex.sage file:

_st_.plot(0, format='notprovided', _p_=plot(cos(x),(x,0,pi),label='$\mathop {\mathgroup \symoperators cos}\nolimits (x)$'))

In this case, SageTeX does exactly what you (unintentionally) asked: it includes the above text as a label. And since TeX does this before \sageplot sees anything, there's nothing SageTex can do.

The above solution with sagesilent is more complicated than necessary, but works because the dollar signs and backslashes inside sagesilent are passed directly to the .sagetex.sage file. Here's a simpler way:

\begin{sagesilent}
  P = plot(cos(x),(x,0,pi),label='$\cos(x)$')
\end{sagesilent}

\sageplot[width=.5\textwidth]{P}