One problem I've always had is trying to make text and/or math text vertically centered in either the tabular or array environments.
Take this for example:
\documentclass{article}
\usepackage{amsmath}
\newcommand{\firstpartial}[1]{\dfrac{\partial}{\partial {#1}}}
\begin{document}
\[
\begin{array}{|l|l|}
\hline
\firstpartial{x}\left[f(x,y)\right] = 2xy & \text{Differentiate with respect to }x\text{, treating }y \text{ as a constant.}\\[4ex]
\hline
\end{array}
\]
\end{document}

I would like to vertically center both the math and the text in both columns. How can I do this?




\\[4ex]? – azetina Jun 12 '14 at 01:03\partialsymbol). – Clarinetist Jun 12 '14 at 01:04