$$\int_0^{\pi} \frac{2 d \theta}{k - cos \theta}$$
So I know this theorem:
$$\int_{-\infty}^{\infty} f(x) dx = 2 \pi i \sum Res f(z)$$ which makes me believe while using this theorem, I eventually need to divide the resulting value by half.
So first things first we need to calculate the singularities and residues right?
So the singularities exist when $\cos \theta = k$. Can someone help from here?
Once we find the residues, we can calculate the integral from $-\infty \to \infty$ and then divide by two right? The variable k is throwing me off because there are some values of k that are large enough so that there will not be a singularity in the denominator right?