Trigonometry! #84

Geometry Level 3

Simplify the following expression to a numerical value. \[3\left(\sin^{4} \left(\frac{3\pi}{2} - \alpha \right) + \sin^{4}(3\pi+\alpha)\right) - 2 \left(\sin^{6} \left(\frac{\pi}{2} + \alpha \right) + \sin^{6}(5\pi-\alpha)\right)\]