limx趋近于0x乘以cot2x 求极限
问题描述：
limx趋近于0x乘以cot2x 求极限
答
lim(x→0) xcot2x
=lim(x→0) xcos2x/sin2x
=lim(x→0) (1/2)*cos2x*(2x/sin2x)
=1/2