Is there an option analogous within the align environment to the left align for right align, i.e. fralign.
MWE:
\documentclass{article}
\usepackage[fleqn]{amsmath} % Instead have [freqn].
%\usepackage[fleqn]{mathtools} Something that will also work for mathtools as well.
\begin{document}
\begin{align*} % Would be fralign* instead.
\sin 2x &= 2sin x\cos x \\
\cos 2x &= \cos^2 x-\sin^2 x &
\end{align*}
\end{document}

fleqnis "fixed length", while inflalignis "full line". Would you better explain your needs? – egreg Oct 20 '11 at 08:07