... Sin120.Cos120..Cos240.Cos 48 0 = 4 1 Sin240.Cos240.Cos 48 0 = 8 1 Sin 48 0.Cos 48 0 = 16 1 Sin960 = 16 1 Cos60 => A = 16 1 (0,5®) Câu 4(3đ) a) (1 ) AB (-2 ;1) Gọi M ... =+=+02 11 2 012 yxyx => O(4 13 ; 8 9) (0,25đ) .OA(45; 8 15 ) =>OA =64325= 8 13 5 (0,25đ) .Đờng tròn có pt (x - 8 9)2 +(y - 4 13 )2 =64325 Câu 5: (1 ) . (E) có 1 đỉnh ... =>Cos100.A = Cos100. Sin100.Cos200.Cos400 (0,25 đ) =2 1 2 Cos100. Sin100.Cos200.Cos400 = 2 1 Sin200 Cos200.Cos400 =4 1 Sin400.C0s400 = 8 1 Sin800 = 8 1 Cos100...