Question

(usp) sendo sen a=3/5 e cos a =4/5 calcule sen 2 a e cos 2a

Answer 1

Resposta:

sen (2a) = 2.sen (a).cos (a) = 2. (3/5). (4/5) = 2.(12/25) = 24/25

cos (2a) = cos² (a) - sen² (a) = (4/5)² - (3/5)² = 16/25 - 9/25 = 7/25