(sin5 pi / 12 - sin pi / 12) (cos5 pi / 12 + cos pi / 12) =?

(sin5 pi / 12 - sin pi / 12) (cos5 pi / 12 + cos pi / 12) =?

(sin5 pi / 12 - sn pi / 12) (cos5 pi / 12 + cos pi / 12)
= (cos pi / 12 - sin pi / 12) (sin pi / 12 + cos pi / 12)
= cos & # 178; (pi / 12) - sin & # 178; (pi / 12)
= cos (pi / 6)
= (루트 번호 3) / 2