%%
%% Ein Beispiel der DANTE-Edition
%%
%% 2. Auflage
%%
%% Beispiel 09-07-26 auf Seite 427.
%%
%% 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.
%%
%%
%% ====
% Show page(s) 1
%%
%%
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{169.16928pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{49}
\renewcommand\theequation{9.\arabic{equation}}
%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands
\begin{document}
\setlength\delimitershortfall{-2pt}
\begin{align} \begin{bmatrix}
a & b\\
\begin{Vmatrix} A & B\\ C & D \end{Vmatrix}
c & d
\end{bmatrix} \end{align}
\end{document}
