%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 8-2-1 on page 469.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See http://www.latex-project.org/lppl.txt for details.
%%

\documentclass{ttctexamargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}

\StartShownPreambleCommands
\usepackage[leqno]{amsmath}
\StopShownPreambleCommands
\begin{document}
\begin{equation} (a+b)^2 = a^2+2ab+b^2 \end{equation}
\[  \sin^2\eta+\cos^2\eta = 1  \]
\end{document}
