8. Let g(x.-y) : 369. a. Calculate the gradient V9 and the derivative D9 of g. b. Find the (explicit) tangent plane to the (explicit) graph of z : g(a:_.y) above (my) : (3.0). c. Find the approximate value of g(3.1.0.3) by using (a) or (b) above. (The value 2296536484... which you may read from a calculator. is NOT the answer.) d. In which direction does 9 increase at the fastest rate at (3:, y) : (3g 0)? \"That is the steepest rate of increase at (any) : (3. 0)