lim(x→0）[1-x^2-e^(-x^2)]/(sin2x)^4 (等价无穷小代换)
=lim(x→0）[1-x^2-e^(-x^2)]/(16x^4) (0/0型 ,上下求导得)
=lim(x→0）[-2x+2xe^(-x^2)]/(32x^3)
=lim(x→0）[-1+e^(-x^2)]/(16x^2) (等价无穷小代换)
=lim(x→0）(-x^2)/(16x^2)
=-1/16第三步应该是lim(x→0）[-2x+2xe^(-x^2)]/(64x^3)吧？噢，脑筋短路了，应该乘4的。lim(x→0）[1-x^2-e^(-x^2)]/(sin2x)^4(等价无穷小代换)=lim(x→0）[1-x^2-e^(-x^2)]/(16x^4) (0/0型 ，上下求导得)=lim(x→0）[-2x+2xe^(-x^2)]/(64x^3)=lim(x→0）[-1+e^(-x^2)]/(32x^2)(等价无穷小代换)=lim(x→0）(-x^2)/(32x^2)=-1/32