6. Suppose that you are climbing a hill whose shape is given by z = 902 - 0.07x2 - 0.1y? and that you are at the point (40, 70, 300). a) In which direction should you proceed initially to reach the top of the hill fastest? (Give a vector on the xy-plane) b) What will be that greatest rate of increase? (Approximate to two decimal places) c) If you want to maintain your height, that is not go up or down, from that (40,70) location, in which direction should you go