JEE Advance - Mathematics (1986 - No. 26)
Evaluate : $$\int\limits_0^\pi {{{x\,dx} \over {1 + \cos \,\alpha \,\sin x}},0 < \alpha < \pi } $$
$$\frac{\pi \alpha}{\sin \alpha}$$
$$\frac{\pi \alpha}{\cos \alpha}$$
$$\frac{\alpha}{\sin \alpha}$$
$$\frac{\pi}{\sin \alpha}$$
$$\frac{\pi^2}{\sin \alpha}$$