lim趋于0((tanx-x)/(x-sinx))^(cotx-1/x)
2个回答

底数和指数分开求:

底数:

lim tanx-x / x-sinx (0/0形式,求导)

=lim 1/cos^2(x)-1 / 1-cosx (0/0形式,再求导)

=lim 2sinx/cos^3(x) / sinx = 2/sinx * sinx/cos^3(x) = 2/cos^3(x) = 2

指数:

lim cotx-1/x = lim (xcosx - sinx)/(xsinx) (0/0形式,求导)

=lim (cosx - xsinx - cosx)/(sinx + xcosx) (0/0)

=lim -(sinx + xcosx)/(2cosx - xsinx) = 0/2 = 0

所以lim=2^0=1