lim (arctan x-x)/sinx^3 x趋于0,能不能用等价无穷小的替换求解答案是-1/3 ,用洛必达法则求的另外我用等价无穷小的替换,结果为-1/6=(sin x-x)/sinx^3 x趋于0=(cosx-1)/[(cosx^3)*3x^2] x趋于0=(-1/2)x^2/[(cosx^3)*3x^2] x趋于0=(-1/2)/3cosx^3 x趋于0=-1/6
问题描述：
lim (arctan x-x)/sinx^3 x趋于0,能不能用等价无穷小的替换求解
答案是-1/3 ,用洛必达法则求的
另外我用等价无穷小的替换,结果为-1/6
=(sin x-x)/sinx^3 x趋于0
=(cosx-1)/[(cosx^3)*3x^2] x趋于0
=(-1/2)x^2/[(cosx^3)*3x^2] x趋于0
=(-1/2)/3cosx^3 x趋于0
=-1/6
答