Question

Решите,пожалуйста,примеры!

Answer 1

$1.\; \;sin^4 \alpha +sin^2 \alpha cos^2 \alpha +cos^2 \alpha =\\=sin^2 \alpha (sin^2 \alpha +cos^2 \alpha )+cos^2 \alpha =\\\\=sin^2 \alpha \cdot 1+cos^2 \alpha =1\\\\2.\; \; (1+tg \alpha )^2+(1-tg \alpha )^2=1+2tg \alpha +tg^2 \alpha +1-2tg \alpha +tg^2 \alpha =\\=2(1+tg^2 \alpha )=\frac{2}{cos^2 \alpha }$