%% 
%%  Die DANTE-Edition
%%  Ein Beispiel der LaTeX Referenz
%%  3. Auflage
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%%  Copyright (C) 2013 Herbert Voss
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%%  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.
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%%  See http://www.latex-project.org/lppl.txt for details.
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{169.16928pt}
%StartShownPreambleCommands
\usepackage{amsmath}
\newcommand*\dx{\,\mathrm{d}x}
%StopShownPreambleCommands
\begin{document}
\begin{align*}
 \int\limits_1^\infty\frac{1}{x^2}\dx &= 1\\
 \int\limits_1^\infty\mkern-7mu\frac{1}{x^2}
                     \mkern4mu\dx &= 1
\end{align*}
\end{document}