If \(\rm\sin^{−1}\left(\frac{2 a}{1+a^2}\right)+\cos^{−1}\left(\frac{1−a^2}{1+a^2}\right) = \tan^{−1}\left(\frac{2 x}{1−x^2}\right)\), where a, x ∈ (0, 1) then the value of x is