# [Tex/LaTex] How to use an align environment flush left

alignamsmathhorizontal alignmentmath-mode

Is there a way possible to imitate the align environment for math mode commands, without having all writing being placed toward the center on the output page?

MWE:

\documentclass{article}
\usepackage{mathtools}

\begin{document}
\begin{align*}
\cos\theta_1 \cos\theta_2-\sin\theta_1\sin\theta_2 &= \cos(\theta_1 +\theta_2) \\
\sin\theta_1 \cos\theta_2 + \cos\theta_1 \sin\theta_2 &= \sin(\theta_1+\theta_2)
\end{align*}

\end{document}


The amsmath package has a fleqn option which, according to the manual (texdoc amsmath) has the following effect:

Position equations at a fixed indent from the left margin rather than centered in the text column.

Thus:

\usepackage[fleqn]{amsmath}


seems to be what you are after.

The mathtools package loads amsmath internally and passes any unknown arguments on to it. This includes the fleqn option. Thus:

\usepackage[fleqn]{mathtools}


also works.

Here's a comparison of the outputs. The upper one is without fleqn and the lower one with.