Question

Sendo dado senx=2/√12 e cosx= 8/√12 determine sen (2x) e cos 2x

Answer 1

sen (2x) = 2 . sen x . cos x
= 2 . 2/√12 . 8/√12
= 2 . 16/12
= 32/12 = 16/6 = 8/3

cos (2x) = cos² x - sen² x
= (8/√12)² - (2/√12)²
= 64/12 - 4/12
= 60/12
= 5

sen (2x) = 8/3
cos (2x) = 5