# ASIN

**The ASIN function returns the arcsine (in radians) of a given number.**

This function takes a single [Number](../../variable-data-types/the-number-variable-data-type) as input. It outputs another Number: the arcsine, in radians, of the given number.

#### Declaration

```javascript
ASIN(number) -> arcsine
```

&#x20;

#### Parameters

**number** (required, type: `Number`) Any number.

#### Return Values

**arcsine** (type: `Number`) The arcsine, in radians, of the given number.

#### Examples

The following example returns the arcsine of 1. Note that the arcsine of one is ninety degrees, or _0.5π_ radians, but the ASIN function doesn't output an angle in degrees or in radians in terms of pi. Rather, it provides a numerical estimation of the angle in radians:

```javascript
ASIN(1) -> 1.5707963267948966
```

To calculate the arctangent in degrees, the ASIN function must be used in tandem with the [DEGREES](degrees) function, such as in the following example:

```javascript
DEGREES(ASIN(1)) -> 90
```

ASIN can also be used in tandem with the [PI](pi) function to provide insight into how the angle in radians relates to terms of pi, such as in the following example:

```javascript
ASIN(1)/PI() -> 0.5
```
