Упрости выражения

1. \(\sin \left(\dfrac{\pi}{2}-\alpha \right)-\sin \left(\pi -\alpha \right)-\cos \left(\pi -\alpha \right)-\sin \left(2\pi -\alpha \right)\) ;

2. \(\dfrac{\sin \left(\pi +\alpha \right)\cos \left(\dfrac{3\pi}{2} -\alpha \right)\tg \left(\alpha-\dfrac{\pi}{2}\right)}{\cos \left(\dfrac{\pi}{2}+\alpha \right)\cos \left(\dfrac{3\pi}{2} +\alpha \right)\tg \left(\pi +\alpha \right)}\) .

Ответ: 1) [ ]; 2) [ ].