11. A plane flies horizontally at an altitude of 8 miles and passes directly over a tracking station on the ground. How fast is the plane flying if the angle of elevation (angle from ground to plane) is decreasing at a rate of 1/2 radian/minute when the angle is 45 degrees. (12 pts) 12. At what values of x does f(x) = 3x - 8x have an absolute maximum and absolute minimum over the interval [0, 27]. (10 pts)