# [pstricks] graph of an implicit equation

Herbert Voss Herbert.Voss at FU-Berlin.DE
Fri Aug 8 10:49:15 CEST 2008

Hamed Al-Sulami schrieb:

> When I tried to graph the equation "3x=y^(1/2)(y-1)"
>
> I got some  vertical and horizontal lines as part of the graph.
>
> Is there a way to graph it without these lines.

see documentation ...

\documentclass[12pt]{article}
\usepackage{pstricks,pst-func}
\pagestyle{empty}
\parindent=0pt

\begin{document}

\psset{mathLabel=false}
%\psset{xunit=.5,yunit=.3}
\begin{pspicture*}(-1.3,-0.5)(8,10)
\psplotImp[linewidth=1.2pt,linecolor=blue,algebraic](-3,-1)(7,10){9*x^2-y*(y-3)^2}
\psplotImp[linewidth=1.3pt,linecolor=red,algebraic](-2,0)(6,9){3*x-y^(1/2)*(y-3)}
%\psline[linecolor=white,linewidth=3pt](-.67,1)(8,1)
%\psline[linecolor=white,linewidth=3pt](-.67,1.5)(-.67,11)
%\psline[linecolor=black,linewidth=2pt](-.67,0)(10,0)
\psaxes[ticks=all,labelFontSize=\tiny,linewidth=1.4pt]{->}(0,0)(-1,-1)(7,10)
\psdots[linecolor=black,dotscale=1,dotstyle=*](-.67,1)(.67,1)(6,9)
\rput(-.3,10){$y$}
\rput(7.2,-.1){$x$}
\rput(4,3){$x=\frac{1}{3}\sqrt{y}(y-3)$}
\end{pspicture*}

\end{document}

Herbert