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# Math.asin()

The **`Math.asin()`** function returns the inverse sine (in radians) of a number.

## Syntax

```js
Math.asin(x)
```

### Parameters

- `x`
  - : A number between -1 and 1, inclusive, representing the angle's sine value.

### Return value

The inverse sine (angle in radians between <math><semantics><mrow><mo>-</mo><mfrac><mi>π</mi><mn>2</mn></mfrac></mrow></semantics></math>, inclusive) of `x`. If `x` is less than -1 or greater than 1, returns `NaN`.

## Description

Because `asin()` is a static method of `Math`, you always use it as `Math.asin()`, rather than as a method of a `Math` object you created (`Math` is not a constructor).
