Definition and Usage
定义与用法

The cos() method returns the cosine of a number.
cos() 方法可以返回数值的余弦值

Syntax
语法

Math.cos(x)

Tips and Notes
尝试与演示

Note: The cos() method returns a numeric value between -1 and 1, which represents the cosine of the angle.
注意：cos()方法返回的数值在-1到1之间。这个值代表了余弦角度。

Example
举例

In the following example we will return the cosine of different numbers:
在下面的举例中我们将不同的数值的余弦值返回出来：

<script type="text/javascript">

document.write(Math.cos(3) + "<br />")
document.write(Math.cos(-3) + "<br />")
document.write(Math.cos(0) + "<br />")
document.write(Math.cos(Math.PI) + "<br />")
document.write(Math.cos(2*Math.PI))

</script>

The output of the code above will be:
输出结果：

-0.9899924966004454
-0.9899924966004454
1
-1
1

Try-It-Yourself Demos
尝试与演示

cos()
How to use cos() to get the cosine of some numbers.
怎样使用cos()来得到一些数字的余弦值

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