Correct answer is D.\(\frac{2a}{1-a^2}\)
We are given that,
sin-1\((\frac{2a}{1+a^2})\) + cos-1\((\frac{1-a^2}{1+a^2})\) = tan-1\((\frac{2x}{1-x^2})\)
Where, a, x ∈ (0, 1).
We need to find the value of x.
Using property of inverse trigonometry,

Taking tangent on both sides,
