Se considera triunghiul ABC in care AB=4,BC = 6 si Ac =8 Determinati cos A /pls

Răspuns :

[tex]BC^2=AC^2+AB^2-2AB*AC*cosA[/tex]
[tex]36=64+16-2*4*8*cosA[/tex]
-44=-64cosA
cosA=44/64
cosA=11/16