Answer:
Below.
Step-by-step explanation:
We need to prove this identity by taking the left side and trying to transform it to the right side.
LHS = sin(150 + x) + sin(150 − x)
= sin 150 cos x + sin x cos 150 + sin 150 cos x - sin x cos 150
= 2 sin 150 cos x
= 2 * 1/2 * cos x
= cos x = RHS.
So it is proved.
