sin 50°.
The easiest way to solve this problem is using sum of angles formula as follow:
sin (u + v) = sin u cos v + cos u sin v
expressing the following function as a function of a single angle.
sin 30° cos 30° + cos 20° sin 30°
sin (u + v) = sin u cos v + cos u sin v Where u = 20°, and v = 30°
sin (20° + 30°) = sin 30° cos 30° + cos 20° sin 30°
sin 50° = sin 30° cos 30° + cos 20° sin 30°