lliJ. This exercise is used in Section 13.5. Let f : [a, b] --+ R be C1 on [a, b]

with f'(t) =f. 0 for t E [a,b]. Prove that the explicit curve x = f-1(y), as y runs from f

(a) to f(b), is orientation equivalent to the explicit curve y = f(x), as x runs from a to b.