Question

what is the value of cos 120

Answer 1

cos 120°
= cos (180°-60°)
= -cos 60°
= -1(1/2)
= -1/2

I hope this helps you ^_^

Answer 2

Answer:

cos 120°=1/2

Explanation:

cos 120

cos (90+30)

due to the angle π/2 cos change to sin.

hence sin 30

sin 30 =1/2

hence sin 30 = cos 120 =1/2