Let P, Q, and W each be functions from R' to R'. Define f(x, y, z) by f (x, y, 2) = ( P()at + J Q()at+ [ w(t)at) Let u = Vf. Part 1: Find u. Part 2: Let S be the upper unit hemisphere in 3D, which is an open surface, with boundary I' correponding to the unit circle, parameterized by s. Let T(s) be the tangent to that boundary. So, to be clear, S is the set of all points satisying x2 + y? + 22 =1, with z 2 0. Find [V x u] . T(s)ds You must explain your