1.
The value of tan⁡−1[1−sin⁡x+1+sin⁡x1−sin⁡x−1+sin⁡x]\tan^{-1} \left[ \frac{\sqrt{1-\sin x}+\sqrt{1+\sin x}}{\sqrt{1-\sin x}-\sqrt{1+\sin x}} \right] (∀x∈[0,π/2]\forall x \in [0, \pi/2]) is equal to