1.
tan⁡−1(1−x2−1x)+sin⁡−1(2x1+x2)\tan^{-1}\left(\dfrac{\sqrt{1 - x^2} - 1}{x}\right) + \sin^{-1}\left(\dfrac{2x}{1 + x^2}\right) (where x≠0x \neq 0) is equal to