# How to Use the Math.asin() Method in JavaScript

Contents

In this article, you will learn how to use the Math.asin() method in JavaScript.

## Using the Math.asin() method in JavaScript

The Math.asin() method is a built-in function in JavaScript that returns the arcsine (in radians) of a given number. The input parameter must be a value between -1 and 1. If the parameter is outside of this range, the method will return NaN (not a number).

### Syntax

The syntax for using the Math.asin() method is:

`Math.asin(x)`

where x is the input parameter that represents the sine of an angle.

### Examples

#### Using Math.asin() to calculate the arcsine of a number

```
const x = 0.5;
const arcsine = Math.asin(x);
console.log(arcsine); // 0.5235987755982989
```

In this example, the input parameter is 0.5, which represents the sine of an angle. The output is the arcsine of 0.5 in radians, which is approximately 0.5236.

#### Using Math.asin() with a value outside the range of -1 to 1

```
const x = 2;
const arcsine = Math.asin(x);
console.log(arcsine); // NaN
```

In this example, the input parameter is 2, which is outside the range of -1 to 1. Therefore, the output is NaN.

#### Using Math.asin() with a negative value

```
const x = -0.7;
const arcsine = Math.asin(x);
console.log(arcsine); // -0.775397496610753
```

In this example, the input parameter is -0.7, which represents the sine of an angle. The output is the arcsine of -0.7 in radians, which is approximately -0.7754.

Note: The output of the Math.asin() method is always in radians. If you want to convert the result to degrees, you can use the following formula:

`degrees = radians * (180 / Math.PI)`

where radians is the output of the Math.asin() method.