Find the range of f(x)=11+e−xf(x) = \frac{1}{1 + e^{-x}}f(x)=1+e−x1.
(0,1)(0, 1)(0,1)
[0,1][0, 1][0,1]
(0,∞)(0, \infty)(0,∞)
(1,∞)(1, \infty)(1,∞)