%%
%% An UIT Edition example
%%
%% Example 04-13-1 on page 62.
%%
%% 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}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands
\newcommand*\diff{\mathop{}\!\mathrm{d}}
\StopShownPreambleCommands
\begin{document}
\[ \oint_{U(r)}H\diff r=\ointop_{U(r)}H\diff r=\frac{I}{2\pi r_0}\oint_{U(r)}
\diff r=\frac{I}{2\pi r_0}\oint_{U(r)}\diff r=I \]
\end{document}
