%% Ein Beispiel der DANTE-Edition

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%% Ein Beispiel der DANTE-Edition
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%% 2. Auflage
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%% Beispiel 09-03-6 auf Seite 384.
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%% Copyright (C) 2016 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{169.16928pt}
\setlength\parindent{0pt}
\setcounter{section}{3}
\setcounter{equation}{5}
\renewcommand\theequation{9.\arabic{equation}}
%StartShownPreambleCommands
\newcommand*\diff{\mathop{}\!\mathrm{d}}
%StopShownPreambleCommands
\begin{document}
\begin{equation}
f(x)= \int\frac{\sin x}{x}\diff x \end{equation}
\renewcommand*\theequation{%
\thesection-\Alph{equation}}
\begin{equation}
f(x)= \int\frac{\sin x}{x}\diff x
\end{equation}
\end{document}