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Analytical solution to this integral?

Dear All,

I am currently seeking an analytical model for condensation upon various geometries. I am updating a legacy code, which needs an analytical expression to be entered.

My work on this has led me to the point where I need to evaluate the following integral:
$\int\frac{(a+2b\cos{\alpha})\sin{\alpha}}{3(a+b\cos{\alpha})\cos{\alpha}}.d\alpha$

Can anyone think of a suitable technique to evaluate this integral analytically? I cannot think of a suitable substitution or transformation.

Many thanks,
T

solution for the integral

(-log(cos(alpha)b+a) - log(cos(alpha)))/3

That was quick!

Thank you very much ramesh - that worked a treat.

Since a technique was asked in the original question, I would add the following. Since $\sin\alpha d \alpha = -d(\cos\alpha)$ the integral becomes an integral of a rational polynomial. You rewrite integrand as $A/(a + b\cos\alpha) + B/\cos\alpha$ which can then be integrated.