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The value of integral ∫−π/2π/211+esin⁡xdx\int_{-\pi/2}^{\pi/2} \frac{1}{1+e^{\sin x}}dx is

Solution

✅ Correct Option: 2

Let I=∫−π/2π/2dx1+esin⁡xI=\int_{-\pi/2}^{\pi/2}\frac{dx}{1+e^{\sin x}}. Replacing xx by −x-x gives I=∫−π/2π/2esin⁡x1+esin⁡xdxI=\int_{-\pi/2}^{\pi/2}\frac{e^{\sin x}}{1+e^{\sin x}}dx.

Adding, 2I=∫−π/2π/21 dx=π2I=\int_{-\pi/2}^{\pi/2}1\,dx=\pi, so I=π2I=\frac{\pi}{2}.

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