Question

Sin 120 ( 2 Cos 120 - Sin^2 150 )

Nb: ^ = pangkat

Answer 1

Cari satu satu
sin 120= sin(180-60) = sin 60 = 1/2 √3
cos 120 = cos(180-60) = - cos 60 = - 1/2
sin 150 = sin (180-30) = sin 30 = 1/2

sin 120 ( 2 cos 120 - sin² 150) =
= 1/2 √3 { (2 (-1/2) - (1/2)²}
= 1/2 √3 ( -1 - 1/4)
= 1/2 √ 3 ( - 5/4)
= - 5/8 √3