%%
%% Ein Beispiel der DANTE-Edition
%%
%%
%% Copyright (C) 2008 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{190.324pt}
\setlength\parindent{0pt}
\StartShownPreambleCommands
\usepackage{pst-func,multido}
\StopShownPreambleCommands
\begin{document}
\begin{pspicture*}(-5,-2)(5.5,2)
\pscircle(0,0){1}\psaxes{->}(0,0)(-5,-1.5)(5.5,2)
\multido{\rA=0.01+0.2}{5}{%
\psplotImp[linewidth=1pt,linecolor=blue,polarplot](-6,-6)(5,2.4){
r dup mul 1.0 r div sub phi sin dup mul mul \rA\space sub }}
\rput[lb](0.5,1.3){$f(r,\phi)=\left(r^2-\frac{1}{r}\right)\cdot\sin^2\phi=0$}
\end{pspicture*}
\end{document}
