%%
%% Der LaTeX-Begleiter, zweite Auflage (September 2005)
%%
%% Beispiel 8-2-29 von Seite 496.
%%
%% Copyright (C) 2005 Frank Mittelbach, Michel Goossens,
%% Johannes Braams, David Carlisle, and Chris Rowley
%%
%% Uebersetzung: Copyright (C) 2005 Claudia Krysztofiak,
%% Rebecca Stiels und Frank Mittelbach
%%
%% 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.
%%
\documentclass{lb2examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{197.4372pt}
\StartShownPreambleCommands
\usepackage[leqno]{amsmath}
\StopShownPreambleCommands
\begin{document}
\begin{gather} \raisetag{-10pt}
\text{Vorzeichenfunktion: \ }
\mathcal{S}(x) = \begin{cases}
-1 & x < 0 \\
0 & x = 0 \\
1 & x > 0
\end{cases}
\end{gather}
\end{document}
