\documentclass[preview]{standalone}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\begin{document}
\begin{align*}
\special{dvisvgm:raw <g id='unique000'>}\cos(\pi) = -1\special{dvisvgm:raw </g>}
\end{align*}
\end{document}