\documentclass{article}
\usepackage{pst-plot}
\usepackage{xepersian}

\settextfont{XB Niloofar}
\setdigitfont{Persian Modern}

\begin{document}

\begin{figure}
\begin{center}
\begin{pspicture}(-6,-6)(6,6)
\psaxes[labels=none]{<->}(0,0)(-5.75,-5.75)(5.75,5.75)
\psplot[algebraic]{-4}{4}{tan(x)^3}
\end{pspicture}
\end{center}
\end{figure}

\end{document}