\documentclass[a4paper]{article} \usepackage{pst-plot} \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc} \SpecialCoor \pagestyle{empty} \begin{document} Équation : \[ z=\frac{a}{x-r} \] $r$ rayon de l'ouverture supérieure. \begin{center} \begin{pspicture}(-1,-1)(10,10) \psframe(0,0)(8,10) \psaxes(0,0)(8,10) \pstVerb{% /H 10 def /R 8 def /r 3 def /a H R r sub div def /h a R r sub div def /x0 a H div r add def}% \pscustom[linestyle=none]{% \psline(0,0)(! 0 H)(!x0 H) \parametricplot{x0}{R}{% t a t r sub div}% \psline(! R h)(! R 0)% \fill[fillstyle=vlines]} \parametricplot[linecolor=red,linewidth=2\pslinewidth]{x0}{R}{% t a t r sub div}% \end{pspicture} \end{center} \begin{center} \begin{pspicture}(-1,-1)(10,10) \psframe(0,0)(8,10) \psaxes(0,0)(8,10) \pstVerb{% /H 8 def /R 4.5 def /r 2 def /a 5 def /xI r a add def /theta 1 H R div atan def /alpha 90 theta sub def /cosT 1 1 H R div dup mul add sqrt div def /zI H R div r a add mul neg H add a cosT div add def}% \pscustom[linestyle=none]{% \psline(0,0)(! 0 H)(! r H)(!r zI) \parametricplot{180}{180 theta add}{% t a t cos mul r add a add a t sin mul zI add}% \psline(! a 180 theta add cos mul r add a add a 180 theta add sin mul zI add)(! R 0)% \fill[fillstyle=vlines]} \psset{linecolor=red,linewidth=2\pslinewidth} \psline(0,0)(! 0 H)(! r H)(!r zI) \parametricplot{180}{180 theta add}{% t a t cos mul r add a add a t sin mul zI add}% \psline(! a 180 theta add cos mul r add a add a 180 theta add sin mul zI add)(! R 0)(0,0)% \end{pspicture} \end{center} \end{document}