%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 7-7-9 on page 390.
%%
%% 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{207.0pt}
\StartShownPreambleCommands
\usepackage{amsmath,txfonts}
\StopShownPreambleCommands
\begin{document}
A problematic example:
\[ t[u_1, \dots, u_n] = \sum_{k=1}^n
   \binom{n-1}{k-1} (1-t)^{n-k}t^{k-1}u_k \]
\end{document}
