The greatest value of the function F(x) =
∫4x t2−8t+16dt on [0,5] is
5
1/3
4
2/3
F′(x)=x2−8x+16=(x−4)2>0 for x∈[0,5]−{4}
So the greatest value of F is F(5)
=∫45 (t−4)2dt=13