9) a) Show that if f(1) is differentiable on R and that f'(r) : 0 for all 1' E R then f(1) : f(0) for all 1' E R1 1)) Assume that at) is such that f'(1) : f(1) for all I E R. Show that there exists a constant C E R such that f (1) : Ce? (Hint: Let 9(1?) : 10(1) and show that it is a constant function.) gar