%% 
%%  A DANTE-Edition example
%% 
%%  Example 36-00-80 on page 801.
%% 
%%  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[dvipsnames]{pstricks}
\usepackage{pst-plot}

\begin{document}
\begin{pspicture}(-3.5,-3.5)(3.5,3)
\psset{linewidth=1mm,polarplot=true,plotpoints=5000}%
\psplot[linecolor=Blue,fillstyle=solid,fillcolor=BlueGreen]{0}{360}{%
  x 2 mul cos 2 mul abs 6.25 mul sqrt}
\psaxes[ticksize=3pt,linewidth=0.2pt]{->}(0,0)(-3.5,-3.5)(4,3.75)%
\uput[0](0,4){$y$}
\uput[-90](3.5,0){$x$}
\end{pspicture}
\end{document}