This deals with inverse functions: suppose g(x) is the inverse of f(X) and G(X) = 1/g(X). If f(3) = 3 and f'(3) = 1/9, find G'(3). Does anyone know how to answer this question? Thanks. I was thinking of using the formula g'(x) = 1/f'(g(X)), but the G(X) is throwing me off.