Converted by
Mathematica
May 22, 2001
![[Graphics:../Images/Pratica5_gr_42.gif]](../Images/Pratica5_gr_42.gif)
![[Graphics:../Images/Pratica5_gr_43.gif]](../Images/Pratica5_gr_43.gif)
![[Graphics:../Images/Pratica5_gr_44.gif]](../Images/Pratica5_gr_44.gif)