\documentclass{article}

\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}\int_{1}^{3} [(e^3/x)/(x^2)]\, dx\end{equation*}
\end{document}

Sorry,the html format does not work...

How to find the integral of [e^(3/x)]/(x^2) from 1 to 3 ??

Btw, does anyone know any website that I can figure out how to make those math symbols???