Очень срочно нужен номер 776

Решите задачу:

$1)\; \; 1+sin(\pi - \beta )cos(\frac{3\pi}{2}- \beta )=1+sin \beta \cdot (-sin \beta )=1+sin^2 \beta \\\\2)\; \; 1+tg \beta \cdot tg2 \beta =1+\frac{sin \beta \cdot sin2 \beta }{cos \beta \cdot cos2 \beta }= \frac{cos \beta \cdot cos2 \beta +sin \beta \cdot sin2 \beta }{cos \beta \cdot cos2 \beta } =\\\\= \frac{cos(2 \beta - \beta )}{cos \beta \cdot cos2 \beta } =\frac{1}{cos2 \beta }\\\\3)\; \; 1-tg(\frac{3\pi}{2}- \beta )ctg(\frac{\pi}{2}- \beta )=1-ctg \beta \cdot tg \beta =1-1=0$

$4)\; \; ctg \alpha -ctg2 \alpha = \frac{cos \alpha }{sin \alpha } - \frac{cos2 \alpha }{sin2 \alpha } = \frac{cos \alpha \cdot sin2 \alpha -cos2 \alpha \cdot sin \alpha }{sin \alpha \cdot sin2 \alpha } =\\\\= \frac{sin(2 \alpha - \alpha )}{sin \alpha \cdot sin2 \alpha } =\frac{1}{sin2 \alpha }$