The Go programming language uses the **`Expm1`** function to find the value of $e$ raised to the power equaling the input $x$, minus $1$. This is the same as $e^x$ -1, where $x$ is the input.

To use this function, you must import the `math` package in your file and access the `Expm1` function within it using the `.` notation (`math.Expm1`). Here, `Expm1` is the actual function, while `math` is the Go package that stores the definition of this function.

# Function definition

The definition of the `Expm1` function inside the `math` package is:


# Parameters
The `Expm1` function takes a single argument of type `float64`. This argument represents the number $x$ in the formula $e^x$ -1.


# Return value

The `Expm1` function returns a single value of type `float64`, which results from raising $e$ to the power of $x$, minus $1$ ($x$ being the input `float64`).

 ﻿An exception to the above statements is when you pass something that is positive infinity, negative infinity, or `NAN` as an argument:

* `+Inf`: If the argument has a positive infinite value, the return value will be exactly the same as the argument, i.e., `+Inf`.

* `-Inf`: If the argument has a negative infinite value, the return value will be -1.

* `NAN`: If a `NAN` argument is passed, the return value is also `NAN`. 




# Examples



Following is a simple example where we find out the `Expm1` value of `5`:

package main

import (
	"fmt"
	"math"
)

func main() {
	x := 5.0
	y := math.Expm1(x)
	fmt.Print(x, "'s exponential value minus 1 is ", y)
}

The following example shows how the `Expm1` function handles infinite valued arguments, for which we use the `Inf` function:

> The `Inf` function returns an infinite value with a sign matching the sign of the argument that it is given.

package main

import (
	"fmt"
	"math"
)

func main() {
	x := math.Inf(-1)
	y := math.Expm1(x)
	fmt.Print(x, "'s exponential value minus 1 is ", y)

	fmt.Print( "\n")


	a := math.Inf(1)
	b := math.Expm1(a)
	fmt.Print(a, "'s exponential value minus 1 is ", b)

}

What is the Expm1 function in Golang?

Golang's Expm1 function calculates $e^x - 1$, handling float64 inputs, infinities, and NANs. Import "math" to use it.