I am having some trouble with these problems

1a. Find the gradient of f(x, y) = x"3 + 2y"2 + 5 1b. At the point (2,1), and direction being find directional derivative 10. What direction should you move in to descend on the surface at the maximum rate when being above the surface point (2, 1, 15)? What about ascend? What is the rate of change? 2. Find the gradient of f(x, y, z) = 3 e"x + z "2 In (y) + x"3 2 at the point (0, 1, 3), then find the directional derivative of the function at the point (0,1,3) in the direction of the vector