Answer:
[tex] = \frac{\sin(2 \alpha ) + \cos(2 \alpha ) - \cos(6 \alpha ) }{ \sin(4 \alpha ) + 2 { \sin }^{2} \alpha - 1} \\ = \frac{ \sin( - 270) + \cos( - 270) - \cos( - 810) }{ \sin( - 540) + 2 { \sin }^{2}( - 135) - 1 } \\ = \frac{1}{ - 2} \\ = - 0.5[/tex]
