π 6 a 2 √ 2 2 a √ 2 √ 3 2 a a π 3 π 4 a a 2 = = 3 2 1 2 ; ; sin = 12 √ sin π3 = 23 π 6 cos π 4 = √ 2 2 ; cos π 4 = √ 2 2 π 6 cos cos π 6 π 3 √ a 2 √ 2 2 a √ 2 √ 3 2 a a π 3 π 4 a a 2 3 2 1 2 ; ; sin π6 = 12 √ sin π3 = 23 cos π4 = √ 2 2 ; cos π4 = √ 2 2 π 6 cos π6 = cos π3 = √ a 2 √ 2 2 a √ 2 √ 3 2 a a π 3 π 4 a a 2 3 2 1 2 ; ; sin π6 = 12 √ sin π3 = 23 cos π4 = √ 2 2 ; cos π4 = √ 2 2 π 6 cos π6 = cos π3 = √ a 2 √ 2 2 a √ 2 √ 3 2 a a π 3 π 4 a a 2 cos π6 = cos π3 = √ 3 2 1 2 ; ; sin π6 = 12 √ sin π3 = 23 cos π4 = √ 2 2 ; cos π4 = √ 2 2 http://chingatome.net