Let f(x) = 0x (t + (1 - et ) )dt, x R. Then, x 0 f(x)x3 is equal to
- 16
- - 16
- 23
- - 23
Answer
(2) - 16
Solution
f(0) = 0 ⇒ 00 form; f'(x) = x + (1 - ex) (Leibnitz rule)
L'Hôpital: L = x 0 x + (1 - ex)3x2 ( 00 )
= x 0 1 - ex (1 - ex)6x ( 00 )
= x 0 -ex (1 - ex) - e2x (1 - ex)6
= -1 - 06 = - 16
Answer: (2)