Converting Between Products and Sums

Question

[sin(2θ + 7θ) + sin(2θ - 7θ)] = _____

A. cos2θcos7θ

B. cos2θsin7θ

C. sin2θcos7θ

D. sin2θsin7θ

Answer 1

sin x cos y = (1/2)[sin(x+y)+sin(x-y)] ... and I had to look this one up too.

You plug in the values to get the answer!