Question

Sederhanakan bentuk trigonometri 2 sin^2(a/2) - 1 =
please tolong yaaa

Answer 1

Cos 2a = 1 - 2sin^2 a => 2sin^2 a = 1 - cos 2a

2sin^2 (a/2) - 1 = (1 - cos 2(a/2) ) - 1 = -cos a