$\int \frac{\sin\frac{5x}{2}}{\sin\frac{x}{2}} dx$ is equal to\\ (1) $x + 2\sin x + \sin 2x + c$\\ (2) $2x + \sin x + \sin 2x + c$\\ (3) $x + 2\sin x + 2\sin 2x + c$\\ (4) $2x + \sin x + 2\sin 2x + c$