2 номер. Нужно решение а не просто ответ.

Решите задачу:

$\frac{1+cos(2\alpha+\frac{7\pi}{2})+sin(2\alpha+\frac{9\pi}{2})}{1-cos(2\alpha-\frac{7\pi}{2})+sin(2 \alpha+\frac{7\pi}{2})}= \frac{1+cos(2\alpha+\frac{3\pi}{2})+sin(2 \alpha+\frac{\pi}{2})}{1-cos(2\alpha-\frac{3\pi}{2})+sin(2 \alpha+\frac{3\pi}{2})}= \frac{1+sin2\alpha+cos2\alpha}{1+sin2\alpha-cos2\alpha} =$
$= \frac{sin^2\alpha+cos^2\alpha+2sin\alpha cos\alpha+cos^2\alpha-sin^2\alpha}{sin^2\alpha+cos^2 \alpha+2sin\alpha cos\alpha-cos^2\alpha+sin^2\alpha}= \frac{2cos^2\alpha+2sin\alpha cos\alpha}{2sin^2\alpha+2sin\alpha cos\alpha}=$
$=\frac{cos\alpha(cos\alpha+sin\alpha)}{sin\alpha(sin\alpha+cos\alpha)}= \frac{cos\alpha}{sin\alpha}=ctg \alpha$