If
\[
\int \frac{\sin^2 \alpha - \sin^2 x}{\cos x - \cos \alpha} \, dx = f(x) + Ax + B, \, B \in \mathbb{R}, \text{ then}
\]
\[
\frac{\sin^2 \alpha - \sin^2 x}{\cos x - \cos \alpha} \, dx = f(x) + Ax + B, \, B \in \mathbb{R}
\]
Show Hint
To solve integrals involving trigonometric identities, consider simplifying using standard identities and methods like integration by parts or substitution.
The given integral can be simplified using standard integration techniques. Upon solving the integral, we find that \( f(x) = \sin x \) and \( A = \cos \alpha \).
Thus, the correct answer is option (3).