Let f:(−1,1)→B, be a function defined by f(x)=tan−12x1−x2, then f is both one - one and onto when B is the interval
For−1<x<1,tan−12x1−x2=2tan−1x Range of f(x) = (−π2,π2). ∴ Co-domain of function = (−π2,π2).