\begin{pspicture}(-2,-2)(5,5)
\psset{xunit=1 cm, algebraic=true}
\psaxes{->}(0,0)(-2,-2)(5,5)

% Trouver antécédents
\psline[linecolor=green,linewidth=1pt]{-}(0,2)(0.5,2)
\psline[linecolor=green,linewidth=1pt]{-}(0.5,2)(0.5,0)
\psline[linecolor=green,linewidth=1pt]{-}(0,3)(0.3,3)
\psline[linecolor=green,linewidth=1pt]{-}(0.3,3)(0.3,0)
\psline[linecolor=green,linewidth=1pt]{-}(0,4)(0.2,4)
\psline[linecolor=green,linewidth=1pt]{-}(0.2,4)(0.2,0)

% Images
\psline[linecolor=red,linewidth=1.5pt]{-}(0,2)(0,4.8)

%antécédents
\psline[linecolor=red,linewidth=2pt]{-}(0,0)(0.5,0)

% la fonction inverse
\psplot[linecolor=black,linewidth=1.5pt]{-2}{-0.2}{1/x}
\psplot[linecolor=black,linewidth=1.5pt]{0.2}{5}{1/x}

\end{pspicture}