#3/4 combine

(3) Find the partial derivatives fx, fy of the following functions. (a) f(x,y) = x2y - 3xe" (b) f(x, y) = y sin(xy) (c) f(x, y) = (4) Find all four second partial derivatives. (fax, fyy, fry, fux). f(x, y) = In(xy + yz)