Question

lim(1/x^2-1/xtanx)当x趋于0时的极限怎么求

Answer 1

简单分析一下，答案如图所示

Answer 2

先通分得到：（tanx - x)/(x^2 * tanx) ,tanx与x无穷小替换得：(tanx - x)/(x^2 * x)再用洛必达法则得((secx)^2 - 1)/(3*x^2) = ((sinx)^2)/(3* x^2 * (cosx)^2) ,sinx 与x 无穷小替换得1/(3 *(cosx)^2) = 1/3;