Respuesta :

altavistard
The formula for "average rate of change of a function from x=a to x=b" is

            f(b) - f(a)
arc = ------------------
              b - a

Here that is 

           4^3 - 2^3        64 - 8
arc = --------------- = ------------ = 56/2 = 28 (answer to part b)
              4 - 2                 2