Converted by
Mathematica
June 17, 2001
![[Graphics:../Images/Pratica7_gr_105.gif]](../Images/Pratica7_gr_105.gif)
![[Graphics:../Images/Pratica7_gr_106.gif]](../Images/Pratica7_gr_106.gif)
![[Graphics:../Images/Pratica7_gr_107.gif]](../Images/Pratica7_gr_107.gif)