lim x趋于0[(tanx-sinx)/sinx^3]的极限

问题描述:

lim x趋于0[(tanx-sinx)/sinx^3]的极限

=lim(1/cosx-1)/(sinx)^2
=lim(1-cosx)/(sinx)^2cosx
=lim2(sin(x/2))^2/(sinx)^2
=(1/2)lim[(sin(x/2))^2/(x/2)^2][x^2/(sinx)^2]
=1/2