(6)
f(x)=∫(0->1-cosx) sin(t^2) dt
f'(x) = sinx. sin( (1-cosx)^2)
x->0
f'(x)
= sinx. sin( (1-cosx)^2)
=sinx. sin[ (1/4)x^4+ o(x^4)]
= (1/4)x^5 +o(x^5)
g(x) = x^5/5 +x^6/6 = (1/5)x^5 +o(x^5)
f'(x)是 g(x) 是同价无穷小
f(x)是 g(x) 是高价无穷小
ans : B