\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\usepackage{color}
\pagestyle{empty}
\begin{document}
\begin{equation*}
\dot V(x) = \frac{\partial V}{\partial x} \dot x =  \frac{\partial V}{\partial x} F(x)
\end{equation*}
\end{document}