Срочно!!! Преобразуйте в произведение Cos2a+cos14a+cos6a+cos10a
Cos 2a + cos 14a = 2cos6a cos8a cos 6a + cos 10a = 2cos2a cos8a cos2a + cos 14a + cos 6a + cos10a = 2cos8a (cos2a + cos6a) = 4cos8a cos4a cos3a