tentukan nilai trigonometri berikut cos330°,sin 150°,cot120°

jawab

cos 330= cos (360-30) = cos 30= 1/2√3

sin 150 = sin (180-30) = sin 20 = 1/2

cot 120 = cos (180- 60) = - cot 60 = - 1/3 √3