Is a mathematical function that returns the trigonometric cosine of the specified Angle, in radians, in the specified expression.
一个数学函数，返回指定表达式中以弧度表示的指定角的三角余弦。
2
In particular,cosine of alpha,I can get, well, we know how to find the angle between two vectors.
特别地，能得到α角的余弦值，我们知道如何找两向量的夹角。
3
The product of the effective values of the voltage and current with the cosine of the phase Angle between current and voltage in an alternating-current circuit.