Calculus help!!!!

Question

given that f(3)=2, f'(3)=9, h(x)=1/f(x), find h'(3)

Answer 1

Let's use the quotient rule to find h'(x), where h(x) = g(x)/f(x) and g(x) = 1 and g'(x) = 0.

Then h'(x) = [f(x)·g'(x) - g(x)·f'(x)]/[f(x)]²

h'(3) = [f(3)·g'(3) - g(3)·f'(3)]/[f(3)]²

h'(x) = [2·0 - 1·9]/[2]²

h'(x) = -9/4