+\documentclass{article}
+\usepackage[a4paper,margin=2cm]{geometry}
+\usepackage[latin1]{inputenc}
+\usepackage{pstricks-add,pst-eqdf,pst-func}
+\usepackage{array,amsmath}
+
+%%%%%%%%%%%%%%%%%%
+\def\datRoot{C:/Users/J\"{u}rgen/Desktop/gravitation/}
+
+\begin{document}
+
+\def\eqlancerA{%
+y[2]|y[3]|-d0/m0*y[2]|-d0/m0*y[3]-g0}%
+\def\eqlancerB{%
+y[2]|y[3]|0|-g0}%
+
+\section{Un lancer inclin\'{e} avec du frottement}
+
+Les \'{e}quations diff\'{e}rentielles sont :
+\begin{align*}
+\ddot{x}&=-\frac{d}{m}\dot{x}\\
+\ddot{y}&=-\frac{d}{m}\dot{y}-g
+\end{align*}
+
+\begin{center}
+\begin{pspicture}(-0.5,-0.5)(10,6)
+\pstVerb{
+ /m0 1 def
+ /d0 0.75 def
+ /theta0 60 def
+ /x0 0 def
+ /y0 1 def
+ /v0 10 def
+ /v0x v0 theta0 cos mul def
+ /v0y v0 theta0 sin mul def
+ /g0 9.81 def
+}%
+\psaxes[labels=none,ticks=none]{->}(0,0)(0,0)(10,5)
+\uput[0](10,0){$x$}
+\uput[90](0,5){$y$}
+\rput(!0 y0){%
+\psline[linecolor=gray]{->}(0;0)(!2 theta0 cos mul 2 theta0 sin mul)
+\psline[linestyle=dashed](0,0)(1.5,0)
+\psarc{->}(0,0){1}{0}{!theta0}
+\rput(!2.2 theta0 cos mul 2.2 theta0 sin mul){$\vec{v}_0$}
+\rput(!0.5 theta0 2 div cos mul 0.5 theta0 2 div sin mul){$\alpha$}
+}
+\psequadiff[method=rk4,
+ plotpoints=1000,
+ algebraic,
+ whichabs=0,
+ whichord=1,
+ tabname=XiAYiA
+% ,saveData,filename=XiYi.dat
+]{0}{5}{x0 y0 v0x v0y}{\eqlancerA}%
+\listplot[linecolor=blue]{XiAYiA aload pop}
+\psequadiff[method=rk4,
+ plotpoints=1000,
+ algebraic,
+ whichabs=0,
+ whichord=1,
+ tabname=XiBYiB
+% ,saveData,filename=XiYi.dat
+]{0}{5}{x0 y0 v0x v0y}{\eqlancerB}%
+\listplot[linecolor=red]{XiBYiB aload pop}
+
+\end{pspicture}
+\end{center}
+
+
+
+\end{document}