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# JavaScript Math acos( ) Method

• Last Updated : 27 May, 2021

Below is the example of the Math acos( ) Method.

• Example:

## javascript

 ``
• Output:

`When 1 is  passed as a parameter: 0`

The Math.acos( ) method is used to return the arccosine of a number in radians. The Math.acos() method returns a numeric value between 0 and pi radians. The Math acos() is a static method of Math, therefore, it is always used as Math.acos(), rather than as a method of a Math object created.

Math.acos(x)=arccos(x)=unique y,
where y belongs to [0;pi]
such that cos(y)=x

Syntax:

`Math.acos(value)`

Parameters: This function accepts single parameter as mentioned above and described below:

• value which is a number in radians who arccosine you want to find.

Returns: The Math.acos() function returns the arccosine of the given number in radians.
Below examples illustrate the Math acos( ) method in JavaScript:

• Example 1:

```Input  : Math.acos(1)
Output : 0```
• Example 2:

```Input  : Math.acos(-1)
Output : 3.141592653589793```
• Example 3:

```Input : Math.acos(0)
Output: 1.5707963267948966```

More example codes for the above method are as follows:
Program 1:

## javascript

 ``

Output:

`When 1 is  passed as a parameter: 3.141592653589793`

Program 2:

## javascript

 ``

Output:

`When 0 is  passed as a parameter: 1.5707963267948966`

Program 3:

## javascript

 ``

Output:

`When 0.5 is  passed as a parameter: 1.0471975511965979`

Program 4:

## javascript

 ``

Output:

`When 2 is  passed as a parameter: NaN`

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