40 



JORNAL DE SCIENCIAS MATHEMATICAS 



II 



a 

 ~b 

 c 

 b 

 a 



-4^^'i„4+^ + i); 



III 



1 a 



a 1 



b —c 



Í-f-2(p2_r2_4i?r); 



IV 



O a b 



a 1 cos C 

 b cos C 1 



2 



r, 



p. 



H»'- + n)^ 



V 



VI 



— IQSS,', 



b a — b 



a -\-b a-{-h 



(a + i)(a4-2ò) 



a + 26 



a 



= -7 ^« n (n -\ - r,) {r, -\- r,) ; 



P 



a 



VII 



b c 



b-\-c a-j-c a-{-b 

 bc ac ab 



= iQSSr, 



VIII 



bc a a^ 

 ac b 6^ 

 ab c c^ 



= — 8 r (p2 _[_ ^2 _|_ 4 7^ ,,) . ^^ . 



IX 



= 8r(7-2 — 3^2_|_47^,.).^^. 



X 



= _(4r2+16i?r + 4p + 3); 



