Tol: K 



MEMORIE DI MATHEMATICA 



JocJzalT.Xm.^. /02. 



'7iq.l 



t- 



P B" B\, B 



^ 8 



B 



-^ 



A 



A" 



TF" 



B 



e 



"7\ 



r' b 



9 



