Converted by
Mathematica
June 17, 2001
![[Graphics:../Images/Pratica7_gr_199.gif]](../Images/Pratica7_gr_199.gif)
![[Graphics:../Images/Pratica7_gr_200.gif]](../Images/Pratica7_gr_200.gif)
![[Graphics:../Images/Pratica7_gr_201.gif]](../Images/Pratica7_gr_201.gif)
![[Graphics:../Images/Pratica7_gr_202.gif]](../Images/Pratica7_gr_202.gif)