# Golang math.Expm1() Function with Examples

Golang | math.Expm1() Function: Here, we are going to learn about the Expm1() function of the math package with its usages, syntax, and examples.
Submitted by IncludeHelp, on August 30, 2021

## math.Expm1()

The Expm1() function is an inbuilt function of the math package which is used to get the e**x - 1, the base-e exponential of x minus 1. Where x is the given parameter. It is more accurate than Exp(x) - 1 when x is near zero.

It accepts a parameter (x) and returns the e**x - 1, the base-e exponential of x minus 1.

Syntax:

```func Expm1(x float64) float64
```

Parameter(s):

• x : The value of float64 type whose base-e exponential of x minus 1 is to be found.

Return Value:

The return type of Expm1() function is a float64, it returns the e**x - 1, the base-e exponential of x minus 1.

Note: Very large values overflow to -1 or +Inf.

Special cases are:

• Expm1(+Inf) = +Inf
If the parameter is the positive infinity, the function returns the same (+Inf).
• Expm1(-Inf) = -1
If the parameter is the negative infinity, the function returns -1.
• Expm1(NaN) = NaN
If the parameter is NaN (Not-A-Number), the function returns the same (NaN).

Example 1:

```// Golang program to demonstrate the
// example of math.Expm1() Function

package main

import (
"fmt"
"math"
)

func main() {
fmt.Println(math.Expm1(0))
fmt.Println(math.Expm1(5))
fmt.Println(math.Expm1(-5))
fmt.Println(math.Expm1(10.5))
fmt.Println(math.Expm1(-10.5))
fmt.Println(math.Expm1(0.01))

fmt.Println(math.Expm1(math.Inf(1)))
fmt.Println(math.Expm1(math.Inf(-1)))
fmt.Println(math.Expm1(math.NaN()))
}
```

Output:

```0
147.4131591025766
-0.9932620530009145
36314.502674246636
-0.9999724635506503
0.010050167084168058
+Inf
-1
NaN
```

Example 2:

```// Golang program to demonstrate the
// example of math.Expm1() Function

package main

import (
"fmt"
"math"
)

func main() {
var x float64
var Expm1X float64

x = 0
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = 0.5
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = 6
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = -6
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = -0.15
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = math.NaN()
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = math.Inf(1)
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)

x = math.Inf(-1)
Expm1X = math.Expm1(x)
fmt.Println("Expm1(", x, ") = ", Expm1X)
}
```

Output:

```0
147.4131591025766
-0.9932620530009145
36314.502674246636
-0.9999724635506503
0.010050167084168058
+Inf
-1
NaN
```