Question

高等数学无穷小的比较？

如图，第答案错了吧？第3题！

Answer 1

Answer 2

(3)

f(x) =x^2 -∫(0->x^2) cos(t^2) dt

f'(x) 

= 2x - 2x.cos(x^4) 

=2x -2x. [ 1- (1/2)x^8 +o(x^8) ]

=x^9 +o(x^9)

g(x) = (sinx)^9 =x^9 +o(x^9)

f'(x), g(x) 是等价于 x^9

ans :A

追问

真棒！