高中数学导数题第一问

Question

如题所述

Answer 1

要用x^k
lim（x-tanx)/x^k
=lim（1-sec^2x)/kx^(k-1)
=lim（c0s^2x-1)/kx^(k-1)
=lim(-2cosxsinx)/(k(k-1)x^(k-2)
=lim(-2sinx)/(k(k-1)x^(k-2)
K=3
3阶本回答被提问者采纳