... sin(2x) = 2sin(x)cos(x) cos(2x) = cos 2 (x) – sin 2 (x) = 1 – 2sin 2 (x) ... sin(x+y) - sin(x-y)] cos(x) cos(y) = (1/2) [cos(x-y) + cos(x+y)] sin ...
確定! 回上一頁