limx->0 (tanx-sinx)/x^3 怎么求?不用洛必达法则
问题描述:
limx->0 (tanx-sinx)/x^3 怎么求?不用洛必达法则
答
limx->0 (tanx-sinx)/x^3
=lim (1/cosx-1)sinx/x^3
=lim 1/cosx-1/x^2
=lim (1-cosx)/x^2cosx
=lim 2sin^x(x/2)/(4*x/2)^2
=2/4
=1/2