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%%  Ein Beispiel der DANTE-Edition
%%  Mathematiksatz mit LaTeX
%%  3. Auflage
%%  Beispiel 11-04-2 auf Seite 243.
%%  Copyright (C) 2018 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
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%StartShownPreambleCommands
\usepackage{mathspec}
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  [Numbers={Lining,Proportional},
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%StopShownPreambleCommands
\begin{document}
\textit{Pythagoras:}
\[ \int\limits_1^{\infty}
   \frac1{\alpha^2}\mathrm d\alpha=1 \]
\end{document}