\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\pagestyle{empty}
\begin{document}
\begin{equation*}
  [f,g](q) = \frac{\partial g}{\partial q} f(q) - \frac{\partial
  f}{\partial q} g(q).
\end{equation*}
\end{document}