JEE Advance - Mathematics (1993 - No. 25)
The value of $$\int\limits_{\pi /4}^{3\pi /4} {{\phi \over {1 + \sin \phi }}d\phi } $$ is ..............
$$\pi \left( {\sqrt 2 + 1} \right)$$
$$\frac{\pi}{2} \left( {\sqrt 2 - 1} \right)$$
$$\pi \left( {\sqrt 2 - 1} \right)$$
$$2\pi \left( {\sqrt 2 - 1} \right)$$
$$\frac{\pi}{4} \left( {\sqrt 2 - 1} \right)$$