那就用lim(x->0) (e^x-1)/x = 1咯
lim (e^x - e^-x) / x
=lim (e^x - 1/e^x) / x
=lim (e^2x - 1) / xe^x
=2*lim (e^2x - 1) / 2x * lim 1/e^x
=2*(1)*1/(1)
=2
那就用lim(x->0) (e^x-1)/x = 1咯
lim (e^x - e^-x) / x
=lim (e^x - 1/e^x) / x
=lim (e^2x - 1) / xe^x
=2*lim (e^2x - 1) / 2x * lim 1/e^x
=2*(1)*1/(1)
=2