The smallest value of the polynomial in [0, 9] is
A. 126
B. 0
C. 135
D. 160
Let
Apply first derivative and get
Apply derivative,
Split middle term and get
Now we find the values of f(x) at x=0, 4, 8, 9
Hence we find that 0 is the absolute minimum value of f(x) in [0,9] at x=0.
So the correct answer is option B.