# GoLang – Find Inverse of Sine – Asin() Function – Examples & Explanation

`Asin()` function is used to find the inverse of a sine in Go language. The inverse of a sine is also known as arcsine.

## `Asin()` Function in Go Language

`math.Asin()` exists is Standard math Library of Go Programming Language. The purpose of this function is to calculate arcsine or the inverse of the sin of any given number (`x` – parameter) within the range of `-1` and `1`.

## `Asin()` Function Syntax in Go Language

The syntax of `Asin()` function in GoLang is

`func Asin(x float64) float64`

Note: `float64` is a data type in go language which has IEEE-754 64-bit floating-point numbers.
Special cases are:
```Asin(±0) = ±0 Asin(x) = NaN if x < -1 or x > 1```

## GoLang `Asin()` Function Parameters

`x` – Any valid Golang number (positive or negative within the range of `-1` and `1`). This parameter is required.
Note: If the `x` parameter is not a number or greater than `1`, `Asin()` function will return an `error`.

## GoLang `Asin()` Function Return Value

`Asin()` function will return a floating point number (a value of the inverse of sine in radians).

## GoLang `Asin()` Function Example 1

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Asin(-1)
fmt.Println(x)
}```

Output:
`-1.5707963267948966`

## GoLang `Asin()` Function Example 2

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Asin(0)
fmt.Println(x)
}```

Output:
`0`

## GoLang `Asin()` Function Example 3

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Asin(1)
fmt.Println(x)
}
```

Output:
`1.5707963267948966`

Note: The unit of output is radian.