%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 0-0-3 on page xxx.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  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{348.0pt}

\StartShownPreambleCommands
\usepackage{feyn}
\StopShownPreambleCommands
\begin{document}
\begin{eqnarray}
\feyn{fcf} &=& \feyn{faf} + \feyn{fpf} + \cdots \\
    &=& \sum_{n=0}^\infty \feyn{fsafs ( pfsafs)}^n
  \end{eqnarray}
\end{document}
