1.
The value of cot⁡−1{1−sin⁡x+1+sin⁡x1−sin⁡x−1+sin⁡x}\cot^{-1}\left\{\dfrac{\sqrt{1 - \sin x} + \sqrt{1 + \sin x}}{\sqrt{1 - \sin x} - \sqrt{1 + \sin x}}\right\}, where π/2<x<π\pi/2 < x < \pi, is