co.sine

cosine的音标和读音：
DJ音标发音： [ˈkouˌsain]
KK音标发音： [ˈkoˌsaɪn]

cosine的词性：
n.Abbr. cos（名词）缩写 cos

1. In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse.
余弦：直角三角形锐角边的边长与叙边的比

2. The abscissa at the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.
余弦：以笛卡儿坐标系原点为圆心的单位圆的圆弦端点的横坐标，弧的长度为x ，如果 x 为正，弧的长度则从（１，0）点按逆时针方向算起，若 x 为负，则按顺时针方向从（１，0）点算起