26. A carpenter is constructing a large cubical storage shed. The volume of the shed is given by V(x) = 4x-x³, where x is the side length in meters a) Determine the average rate of change in volume when the sides lengths are between 1 m and 3 m. (3 marks) b) Determine the instantaneous rate of change when the side length is 2 m using the difference quotient. (3 marks) lim h→0 f(a + h) − f(a) h