Let f (x) = loga (1 + x) / (1-x) (a > 0, a ≠ 1) if loga (1 + x) / (1-x)

Let f (x) = loga (1 + x) / (1-x) (a > 0, a ≠ 1) if loga (1 + x) / (1-x)

The condition can be satisfied when a is greater than 1
The base a is discussed in two cases