设x(x-1)^3=u,(x^2+1)^3=v,a=x-1,b=x^2+1,u=xa^3,v=b^3u'=(xa^3)' =x'a^3+x(a^3)'=(x-1)^3+3x(x-1)^2=a^3+3xa^2v'=3(x^2+1)^2=3b^2,v'/v=3/b(u/v)'=(u'v-uv')/v^2=u'/v - u/v * v'/v=(a^3+3xa^2)/b^3 - (a^3/b^3) * ...