Let \( \alpha \) and \( \beta \) respectively be the maximum and the minimum values of the function \( f(\theta) = 4\left[\sin^{4}\!\left(\frac{7\pi}{2}-\theta\right) + \sin^{4}(11\pi+\theta)\right] - 2\left[\sin^{6}\!\left(\frac{3\pi}{2}-\theta\right) + \sin^{6}(9\pi-\theta)\right],\ \theta \in \mathbb{R}. \) Then \( \alpha + 2\beta \) is equal to:
