My Mathjax commands (makes life easier)

\newcommand{\p}[2]{\frac{\partial #1}{\partial #2}} \newcommand{\f}[2]{\frac{ #1}{ #2}} \newcommand{\l}[0]{\left(} \newcommand{\r}[0]{\right)} \newcommand{\mean}1{\langle #1 \rangle}\newcommand{\e}[0]{\varepsilon} \newcommand{\ket}1{\left|#1\right>} \newcommand{\bra}1{\left<#1\right|} \newcommand{\braoket}[3]{\left<#1\right|#2\left|#3\right>}