%% 
%%  An UIT Edition example
%% 
%%  Example 04-09-5 on page 58.
%% 
%%  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{375.57637pt}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{34}
\renewcommand\theequation{4.\arabic{equation}}
\StartShownPreambleCommands
\makeatletter
\newenvironment{smallequation}[1]{%
  \skip@=\baselineskip#1\baselineskip=\skip@\equation
}{\endequation \ignorespacesafterend}
\makeatother
\StopShownPreambleCommands
\begin{document}
If you want to set a formula in very small font, you must change
the font size to a very small value using the \texttt{\textbackslash tiny}
command outside the display environment, and end the paragraph after the
formula\ldots
\begin{smallequation}{\tiny}
  \int_1^2\,\frac{1}{x^2}\,\mathrm{d}x=0.5
\end{smallequation}
\end{document}