1. (a) Use chain rule to find the partial derivatives ì¿ and of z = ez?v, where x (u, u) = Viv and y(u, u) = u. (b) Express and ì¿ only in termis of u and u and evaluate at (u, u) = (1,1). 0 2. (a) Find the directional derivative of f(z, y, z) = zy2d at P2, 1,1) in the direction from P to (0,-3,5) (b) In which direction is the directional derivative maximized? What is the steepest rate of increase of f at P? 3. Consider the surface xy+yz+ zx = 5. Find (a) the tangent plane at (1,2,1) and (b) the normal line at (1,2,1)