%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 8-7-6 on page 506.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%% Johannes Braams, David Carlisle, and Chris Rowley
%%
%% 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{159.0pt}
\StartShownPreambleCommands
\usepackage{amsmath}
\StopShownPreambleCommands
\begin{document}
\[
f_p (x) =
\begin{cases}
\frac{1}{\smash[b]{p}} & x = p \\
\frac{\strut
\smash[t]{\frac{(1 - x)^{\frac{1}{2}} }
{ x - \sin (x - p) } } }
{\sqrt{1 - p} \, \cos (x - p)} & x \neq p
\end{cases}
\]
\end{document}
