Note: You must show all your works to get full marks. 1. (5 marks) Two cars are seen leaving an intersection around noon. Car A is heading north at a rate of 40 km/h, while Car B is heading west at a rate of 30 km/h. An hour later, how fast is the distance between the two cars changing? B 2 2 2. (5 marks) Suppose that y = f(x) = - x2 + 16x 128 at 8' f (20 ) = (2+ 8)2,5 (20 ) = (2 + 8) 3 . Find the domain, critical points, and inflection points, if they exist, of the function. Find intervals on which the function is increasing, decreasing, concave upward, and concave downward. Also, find local maximum and minimum, if any