# GoLang – Find Order-n Bessel – Jn() Function – Examples & Explanation

`Jn()` function is used to find the order-n Bessel function of the first kind in Go language. The standard math package of Go programming language has `Jn()` function.

## Syntax of `Jn()` Function in Go Language

The syntax of `Jn()` function in Go Language is:

```func Jn(n int, x float64) float64
```

Note: `float64` is a data type in Go language which has IEEE-754 64-bit floating-point numbers. And `int` is a signed integer type that is at least 32 bits in size. It is a distinct type, however, and not an alias for, say, int32.
Special cases are:
```Jn(n, ±Inf) = 0 Jn(n, NaN) = NaN```

## Parameters of `Jn()` Function in Go Language

`x ` – Where `x` is any Valid `int` Input value. This parameter is required.
`y` – Where `y` is any Valid `float64` Input value. This parameter is also required.

## Error Handling

If the `x ` or `y` parameter are not numbers (numeric values) `Jn()` function returns an `error `.
If there is no argument (`x` or `y` – input values) passes to the function, then the compiler will produce an `error`.

## Return Value of `Jn()` Function in Go Language

`Jn()` function will return the order-n Bessel function of the first kind..

## GoLang `Jn()` Function Example 1

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Jn(-11, 2)
fmt.Println(x)
}
```

Output:
` -2.3042847583672514e-08`

## GoLang `Jn()` Function Example 2

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Jn(2, 13)
fmt.Println(x)
}
```

Output:
` -0.21774426424195684`

## GoLang `Jn() ` Function Example 3

```package main

import "fmt"
import "math"

func main() {
var x float64
x = math.Jn(-15, -6.21)
fmt.Println(x)
}
```

Output:
`9.95121283853212e-06`