Evaluate the following integral: `int_0^(pi)x/(a^2cos^2x+b^2sin^2x)dx`

Explanation

To evaluate the integral

\[ I = \int_0^{\pi} \frac{x}{a^2 \cos^2 x + b^2 \sin^2 x} \, dx, \]

we can use a symmetry property of definite integrals.

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