Упростите выражения,и поподробней в решение и правильно.

$1)\\ \frac{2cos2}{sin88+cos2} = \frac{2cos2}{sin88+sin88}\\ \frac{2cos2}{2sin88}=\frac{sin88}{sin88}=1$

$2)\\ sin^4a+cos^4a+2sin^2a*cos^2a=(sin^2a+cos^2a)^2=1$

$tg5*tg25*tg45*tg65*tg85 = \\ tg5*tg25*tg45*tg65*tg85 = tg5*tg85=\frac{cos80-cos90}{cos80+cos90}\\ tg25*tg65=\frac{cos40-cos90}{cos40+cos90}\\ tg45=1\\\\ \frac{cos80-cos90}{cos80+cos90}*\frac{cos40-cos90}{cos40+cos90}*1=\\ \frac{cos80}{cos80}*\frac{cos40}{cos40}*1=1$
Ответ 1