# [Tex/LaTex] ERROR: Please use \mathaccent for accents in math mode

errorsfont-encodingsinput-encodings

Why do I get an "ERROR: Please use \mathaccent for accents in math mode." for the following code?

$c=439 450\times10^6\frac{\mathrm{millimètre}}{\mathrm{seconde}}$


I am guessing \usepackage[utf8]{inputenc} is having problems with the accented "è" in "millimètre."

It works fine when you use \text instead of \mathrm. \text is part of amsmath, which is loaded by mathtools

\documentclass{scrartcl}

\usepackage[utf8]{inputenc}

\usepackage{mathtools}

\begin{document}
$c=439 450\times10^6\frac{\text{millimètre}}{\text{seconde}}$
\end{document}


\mathrm won’t create real text, it only changes the math alphabet from italics to recto. But in the math alphabet there are no accent characters like è