Упростите выражения:1) 1-cosA*1+cosA2)cos^2 A *(1-tg^2A)A-значит "альфа"

Решите задачу:

$\begin{array}{l} 1.\left( 1-cos(\alpha )\right) \left( 1+cos(\alpha )\right) .\\ \text{Formula;}a^{2}-b^{2}=(a-b)(a+b).\\ 1-cos^{2}(\alpha )=sin^{2}(\alpha ).\\ 2.cos^{2}(\alpha )(1-tg^{2}(\alpha )).\\ cos^{2}(\alpha )(ctg(\alpha )tg(\alpha )-tg^{2}(\alpha )).\\ cos^{2}(\alpha )tg(\alpha )(ctg(\alpha )-tg(\alpha )).\\ cos^{2}(\alpha )\frac{sin(\alpha )}{cos(\alpha )} (\frac{cos(\alpha )}{sin(\alpha )} -\frac{sin(\alpha )}{cos(\alpha )} ).\\ cos(\alpha )sin(\alpha )\frac{cos(\alpha )cos(\alpha )-sin(\alpha )sin(\alpha )}{sin(\alpha )cos(\alpha )} .\\ cos^{2}(\alpha )-sin^{2}(\alpha )=cos(2\alpha ).\\ \text{Formula;}tg(\alpha )=\frac{sin(\alpha )}{cos(\alpha )} ;\text{ctg(\alpha )=}\frac{cos(\alpha )}{sin(\alpha )} ; \end{array}$