Evaluate: `int_0^pi(xsinx)/(1+cos^2x)\ dx`

Explanation

I = `int_0^pi (xsinx)/(1+cos^2x)dx`........(i)

also using `int_a^b f(x) dx = int_0^pi f(a+b-x) dx`


I = `int_0^pi( (pi-x)(sinx))/(1+cos^2x)dx`........(ii)


adding equation 1 and 2


2I = `pi int_0^pi (xsinx)/(1+cos^2x)dx`
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