Question

Найдите значение выражения

Answer 1

√27cos^2(7π/12)-√27sin^2(7π/12)=√27*(cos^2 (7π/12)-sin^2(7π/12)=
=√27*cOs(2*7π/12)=√27cos(7π/6)=√27cos(π+π/6)=√27(-cos(π/6))=-√27*(√3/2)=-√81/2=-3/2=-1,5
Ответ. -1,5