Consider the surface z = f(x,y) = 3- 6x- 3y and the oriented curve C in the xy-plane given parametrically as 1 where t2 8 X = e - 4t ,y3e - 4t In 3. a. Find z'(t). b. Imagine that you are walking on the surface directly above the curve C in the direction of positive orientation. Find the values of t for which you are walking uphill (that is, z is increasing).