%% 
%%  An UIT Edition example
%% 
%%  Example 04-08-8 on page 54.
%% 
%%  Copyright (C) 2010 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{177.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{30}
\renewcommand\theequation{4.\arabic{equation}}
\StartShownPreambleCommands
\newenvironment{mathspace}[1][3pt]{%
 \setlength{\jot}{#1}\ignorespaces\eqnarray
}{\endeqnarray\ignorespacesafterend}
\StopShownPreambleCommands
\begin{document}
\begin{mathspace}[0pt]
  y & = & d\\
  y & = & c\,\frac{1}{x}+d\\
  y & = & b\,\frac{1}{x^{2}}+cx+d
\end{mathspace}
\end{document}