The problem comes when using multiline display math. When using the environment \begin{align}...\end{align}} then tex4ht will not convert all the equations to one bit-mapped image. This can cause a problem.

Here is a text case

---------------------------------
\documentclass[12pt,titlepage]{article}%
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}%

\begin{document}

\begin{eqnarray*}
v^{2} & =\left( \dot{x}+v_{x}\right) ^{2}+v_{y}^{2}\\
& =\dot{x}^{2}+l^{2}\dot{\theta}^{2}+2\dot{x}l\dot{\theta}\cos\theta
\end{eqnarray*}

\begin{align*}
v^{2} & =\left( \dot{x}+v_{x}\right) ^{2}+v_{y}^{2}\\
& =\dot{x}^{2}+l^{2}\dot{\theta}^{2}+2\dot{x}l\dot{\theta}\cos\theta
\end{align*}

\end{document}
----------------------

tex4ht foo.tex

compare the html output generated by the 2 different commands above. You will see that the second one is not bit mapped math.

thanks
--Nasser