# JavaScript Math asin( ) Method

• Last Updated : 07 Jul, 2020

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

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• Example:
 `<``script` `type``=``"text/javascript"``>``   ``document.write("When 1 is  passed as a parameter: " ``                 ``+ Math.asin(1));```
• Output:
`When 1 is  passed as a parameter: 1.5707963267948966`

The Math.asin( ) method is used to return the arcsine of a number in radians. The Math.asin() method returns a numeric value between -pi/2 and pi/2 radians. The asin() is a static method of Math, therefore, it is always used as Math.asin(), rather than as a method of a Math object created.

Math.asin(x)=arcsin(x)=unique y
where y belongs to [-pi/2;pi/2]
such that sin(y)=x

Syntax:

`Math.asin(value)`

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

• value: This parameter holds a number in radians who arcsine you want to find.

Returns: The Math.asin() method returns the arcsine of the given number in radians.

Below examples illustrate the Math asin() method in JavaScript:

• Example 1:
```Input : Math.asin(1)
Output : 1.5707963267948966```
• Example 2:
```Input : Math.asin(-1)
Output : -1.5707963267948966```
• Example 3:
```Input : Math.asin(2)
Output : NaN```
• Example 4:
```Input : Math.asin(0.5)
Output : 0.5235987755982989```

More example codes for the above method are as follows:

Program 1:

 `<``script` `type``=``"text/javascript"``>``    ``document.write("When -1 is  passed as a parameter: " ``                   ``+ Math.asin(-1));```

Output:

`When -1 is  passed as a parameter: -1.5707963267948966`

Program 2:

 `<``script` `type``=``"text/javascript"``>``    ``document.write("When 2 is  passed as a parameter: " ``                   ``+ Math.asin(2));```

Output:

`When 2 is  passed as a parameter: NaN`

Program 3:

 `<``script` `type``=``"text/javascript"``>``    ``document.write("When 0.5 is  passed as a parameter: " ``                   ``+ Math.asin(0.5));```

Output:

`When 0.5 is  passed as a parameter: 0.5235987755982989`

Supported Browsers: