Find average value of the function!

Question

Find average value of the function f(x)=3x^2 on the interval 1≤x≤3. 

Answer 1

To find the average value of a function you take the integral of the function in that interval and divide by 2. That is:        ½∫f(x)dx  for 1≤x≤3. So the answer should be ½(x³) from 1≤x≤3. So that is ½[(3^3)-(1^3)] = ½(27-1)=26/2=13.