Converted by
Mathematica
June 17, 2001
![[Graphics:../Images/Pratica7_gr_286.gif]](../Images/Pratica7_gr_286.gif)
![[Graphics:../Images/Pratica7_gr_292.gif]](../Images/Pratica7_gr_292.gif)
![[Graphics:../Images/Pratica7_gr_295.gif]](../Images/Pratica7_gr_295.gif)