Question

sin(П/2-а)-sin(П-а)-cos(П-а)-sin(2П-а)

Answer 1

$sin( \frac{\pi}{2}-\alpha)-sin( \pi-\alpha)-cos(\pi-\alpha)-sin(2\pi-\alpha) \\ \\ cos(\alpha)-sin(\alpha)-(-cos(\alpha))-(-sin(\alpha)) \\ \\ cos(\alpha)-sin(\alpha)+cos(\alpha)+sin(\alpha) =2cos(\alpha)$

Answer 2

$Sin( \frac{ \pi }{2}- \alpha )-Sin( \pi - \alpha )-Cos( \pi - \alpha )-Sin(2 \pi - \alpha )=Cos \alpha -Sin \alpha$$+Cos \alpha +Sin \alpha =2Cos \alpha$