凑一下就可以,因为df(x^2)=2xf'(x^2)
所以∫xf(x^2)f'(x^2)dx
=1/2∫[2xf'(x^2)]*f(x^2)dx
=1/2∫f(x^2)df(x^2)
=1/2*1/2*[f(x^2)]^2+C
=1/4*[f(x^2)]^2+C
若满意,请采纳!