Given: f(x)=2 cos x and g(x)=sin x. Which of these expressions is equivalent to (fxg)(π/16)?

Question

a) cos π/8
b) sin π/8
c) cos π/4
d) sin π/4

Please explain the answer, thank you.

Answer 1

since (fxg)(x) = 2cosxsinx
and 2sinxcosx = sin 2x
we would be finding sin(2(π/16)) = sin π/8