\documentclass{ppex}
\nonstopmode
\usepackage {pstcol,pst-plot}
\pagestyle{empty}

\begin{document}
\ResetPreambleCommands
\ReadyForTheFray
\usepackage {pstcol,pst-plot}
\begin{pspicture}(-1,-2.5)(9,2.5)
\psset{xunit=.25mm,yunit=2cm}
\psset{plotpoints=50}
\psplot[linestyle=dashed,linecolor=blue]{0}{360}{x sin}
\psplot[plotstyle=dots,dotstyle=triangle]{0}{360}{x cos}
\psset{plotpoints=200}
\psplot[linecolor=red]{0}{360}{x dup sin exch cos mul}
\end{pspicture}
\end{document}