原式=lim(x→π/2) (1+sinx-1)^{[1/(sinx-1)](tanx)(sinx-1)}
=lim(x→π/2) e^[(tanx)(sinx-1)]
=e^ lim(x→π/2) (sinx-1)/cotx
=e^ lim(x→π/2) cosx/(- csc²x)
=e^0
=1