%% 
%%  A DANTE-Edition example
%% 
%%  Example 30-04-13 on page 612.
%% 
%%  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}
\def\Func{exch RadtoDeg sin -9.81 mul}

\begin{document}
\psset{yunit=1.5,xunit=2,showpoints}
\begin{pspicture}[showgrid](0,-1.5)(3,2)
  \psplotDiffEqn[linecolor=black!40]{0}{3}{1 0}{\Func}
  \psplotDiffEqn[method=adams,linestyle=dashed]{0}{3}{1 0}{\Func}
  \psplotDiffEqn[method=rk4]{0}{3}{1 0}{\Func}
  \rput[rb](2.9,-0.9){Runge-Kutta (rk4)}\rput[rb](1.9,1.3){Euler}
\end{pspicture}
\end{document}