I'm trying to highlight the diagonal elements of a matrix by using fbox
but I failed. I've searched for the problem, some ppl suggest using tikz. I don't want to use it, so I decided to use fbox{}
. Every time I do the following
\documentclass[a4paper, 12pt]{article}
\usepackage{amsmath}
\usepackage{graphicx}
\begin{document}
\begin{align}
\begin{bmatrix}
\sigma_{xx} & \sigma_{yx} \\
\sigma_{xy} & \fbox{\sigma_{yy}} \\
\end{bmatrix}
\end{align}
\end{document}
it throws an error !Argument of \align has an extra}
if I remove \sigma_{}
, it works. Any suggestions?
Best Answer
\fbox
sets its argument in text mode, and\sigma
as well as the subscript requires math mode. So, use\fbox{$\sigma_{yy}$}
or the\boxed
version supplied byamsmath
:Also, there's no need for
align
here, and I'd rather use anequation
(if you want it numbered) or\[
...\]
if not.