limx趋向于无穷x^2+2x-4/x^3-x^2

limx趋向于无穷x^2+2x-4/x^3-x^2
limx趋向于无穷x^2+2x-4/x^3-x^2

limx趋向于无穷x^2+2x-4/x^3-x^2
用L 'Hopital法则,上下同时求导两次再求极限得
lim2/(6x-2)=o