Question

Упростите выражение под б и г

Answer 1

$1); ; frac{cos6+cos12+cos36+cos42}{sin87cdot cos15cdot cos24} = frac{(cos6+cos42)+(cos12+cos36)}{sin(90-3)cdot cos15cos24} =\\= frac{2cdot cos24cdot cos18+2cdot cos24cdot cos12}{cos3cdot cos15cdot cos24} = frac{2cdot cos24cdot (cos18+cos12)}{cos3cdot cos15cdot cos24} =\\= frac{2cdot 2cdot cos15cdot cos3}{cos3cdot cos15}=4$

$2); ; frac{sin48-sin60-sin72+sin84}{4cos84cdot sin12cdot sin66} = frac{(sin48+sin84)-(sin60+sin72)}{4cdot cos(90-6)cdot sin12cdot sin66} =\\= frac{2cdot sin66cdot cos18-2cdot sin66cdot cos , 6}{4cdot sin6cdot sin12cdot sin66} = frac{2cdot sin66cdot (cos18-cos, 6)}{4cdot sin6cdot sin12cdot sin66} =\\= frac{-2cdot sin12cdot sin6}{2cdot sin6cdot sin12} =-1$

Answer 2

Спасиииибоо

Answer 3

А как там 2 получилось???