求下列极限lim趋于0(tanx-x)/(x^2sinx) 求救啊

问题描述:

求下列极限lim趋于0(tanx-x)/(x^2sinx) 求救啊

原式=lim(x→0)(tanx-x)/x^3 (等价无穷小)
=lim(x→0)(1/cos^2(x)-1)/(3x^2) (洛必达法则)
=lim(x→0)sin^2(x)/(3x^3)*1/cos^2(x)
=1/3 (等价无穷小)