\begin{pspicture}(-5,-5)(5,5)
\psset{xunit=1 cm, algebraic=true}
\psaxes{->}(0,0)(-5,-5)(5,5)
\psplot[linecolor=black,linewidth=1.5pt]{-5}{-0.2}{1/x}
\psplot[linecolor=black,linewidth=1.5pt]{0.2}{5}{1/x}
\end{pspicture}