%%
%% A DANTE-Edition example
%%
%%
%% 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,pst-func}
\begin{document}
\begin{pspicture*}(-3,-2.2)(3.5,2.5)
\psaxes{->}(0,0)(-3,-2)(3.2,2)
\psplotImp[linewidth=2pt](-5,-2.2)(5,2.4){
/xqu x dup mul def /yqu y dup mul def
xqu yqu add dup mul 2 dup
add 2 mul xqu yqu sub mul sub }
\rput*(2,1.5){%
$\left(x^2+y^2\right)^2-8(x^2-y^2)=0$}
\psplotImp[linewidth=1pt,linecolor=red,
algebraic](-5,-2.2)(5,2.4){%
(x^2+y^2)^2-4*(x^2-y^2) }% Lemniskate a=2
\end{pspicture*}
\end{document}
