
William W. answered 10/25/20
Experienced Tutor and Retired Engineer
Use the product rule for g(x) and the quotient rule for h(x).
The product rule says for u•v, (u•v)' = u'v + uv' so:
g'(x) = f '(x)•sin(x) + f(x)•(sin(x))'
You've been taught what the derivative of sin(x) is, so just use that and plug in x = π/3
The quotient rule says for (u/v) that (u/v)' = (u'v - uv')/v2
u = cos(x) and v = f(x)
u' = -sin(x) and v' = f '(x)
v2 = (f(x))2
Just plug and chug.