Question

Решите,пожалуйста,примеры!

Answer 1

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