\documentclass[11pt]{report}
\input{header}
\pagestyle{empty}
\begin{document}
\psscalebox{1.8}{\arrset{0.8}%
  \begin{pspicture}(-5.5,-2)(5.5,9)
    \arraxes(0,0)(-1,-4)(4,6)
    \psframe(-1,-4)(4,6)
    \psplot[linecolor=blue]{0}{0.79}{1 x 1 sub 2 x sub mul div}
    \psplot[linecolor=blue]{1.21}{1.79}{1 x 1 sub 2 x sub mul div}
    \psplot[linecolor=blue]{2.21}{3}{1 x 1 sub 2 x sub mul div}
    \arrMainVertex(0,-0.5){1}
    \arrMainVertex(3,-0.5){3}
  \end{pspicture}
}
\end{document}
