lim(x->+inf) (1-1/x)^√x=lim [1 + 1 / (-x)]^(-x) * [√x / (-x)]，州耐好岁配合公式lim(y->∞) (1+1/y)^y = e，这里册袜春y = -x=e^-lim 1 / √x=e^0=1
(1/exp(1))^(1/2)
