%% 
%%  Der Mathematiksatz mit LaTeX, 1. Auflage 2009
%% 
%%  Example 3-6-1 on page 29.
%% 
%%  Copyright (C) 2009 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.
%% 

\documentclass[]{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{355.65944pt}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\setcounter{equation}{30}
\renewcommand\theequation{3.\arabic{equation}}
\usepackage[expert,lucidasmallscale]{lucidabr}
\setlength\parindent{0pt}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
Das charakteristische Polynom $f(\lambda)$ der $3\times 3$ Matrix
%
\begin{equation}
\left(\begin{array}{ccc}
a & b & c \\
d & e & f \\
g & h & i
\end{array}\right)
\end{equation}
%
ist gegeben durch die Gleichung
%
\begin{equation}
f(\lambda) =
  \left|\begin{array}{ccc}
          \lambda - a & -b          & -c \\
                   -d & \lambda - e & -f \\
                   -g & -h          & \lambda - i
  \end{array}\right|.
\end{equation}
\end{document}