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%%  An UIT Edition example
%% 
%%  Example 03-02-7 on page 19.
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%%  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.
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%% ==== 
% Show page(s) 1
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\setlength\parindent{0pt}
\usepackage[utf8]{inputenc}
\setcounter{equation}{3}
\renewcommand\theequation{3.\arabic{equation}}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
\begin{eqnarray}
\textrm{right-aligned} & \textrm{centred} & \textrm{left-aligned}\label{eq:eqnarray}\\
\frac{1}{\sqrt{n}} & \frac{\sqrt{n}}{n} & \frac{n}{n\sqrt{n}}
\end{eqnarray}
\end{document}