1.
The value of tan1[1sinx+1+sinx1sinx1+sinx]\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