El] [Ill marks] a] Shew that if x] is differentiable on R and that f F[13) = fer all a: E R, then at) = HID] for all m E R. h) Assunle that f{3:J is such that 1'13) = lm) for all :I.' E R. Shaw that there exists a constant C E R such that x] = Gel. (Hint: Let x] = 51 and show that it is a constant function.) 11