%% 
%%  An UIT Edition example
%% 
%%  Example 10-09-5 on page 218.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  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.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{201.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
\begin{tabular}{|p{5cm}|}\hline
\[ \tan \alpha=
   \frac{\sin\alpha}{\cos\alpha} \]\\
\[ \tan2\alpha=
   \frac{2\tan\alpha}{1-\tan^2\alpha}\]\\
\[ \tan3\alpha=\frac{3\tan\alpha
  -\tan^3\alpha}{1-3\tan^2\alpha} \]\\\hline
\end{tabular}
\end{document}