%% 
%%  A DANTE-Edition example
%% 
%%  Example 30-04-18 on page 615.
%% 
%%  Copyright (C) 2011 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[]{article}
\pagestyle{empty}
\setlength\textwidth{201.70511pt}
\setlength\parindent{0pt}

\usepackage{pstricks-add}

\begin{document}
\psset{unit=5,method=rk4,algebraic,whichabs=0,whichord=1,plotpoints=500,
  linewidth=1pt}
\begin{pspicture}(-1.2,-0.2)(1.2,0.2)
 \psgrid[subgriddiv=5,subgridcolor=black!10,gridlabels=7pt](-1.2,-0.2)(1.2,0.2)
 \psplotDiffEqn[linecolor=red]{0}{12}{0 0 0 0}%
    {y[2]|y[3]|2*Pi*y[3]|4*cos(0.2*Pi*x)-2*Pi*y[2]}
\end{pspicture}
\end{document}
