getting user-defined math function in proper font in beamer

Question

When I use beamer, things like \sin, \cos, etc. appear in the sans-serif font. But if I say

\DeclareMathOperator{\lcm}{lcm}

and then use \lcm inside a math formula, it appears in the cmr font. How can I get it to appear in the sans-serif font like other math functions?

Answer 1

\documentclass{beamer}
\usepackage{amsmath}
\DeclareMathOperator{\lcm}{lcm}

\begin{document}
\begin{frame}{foo}{bar}

\[ \lcm = l\times c\times m \]

\end{frame}   
\end{document}