Define IP: Rn x Rn →R by IP (x, y) = .
(a) Find D(IP) (a,b) and (IP)’ (a,b).
(b) If f,g: R → Rn are differentiable, and h: R → R is defined by h(t) = , show that hI
(a) = .
(c) If f: R → Rn is differentiable and |f(t) = 1 for all t, show that = 0.