# Java – Find e Raise to Power x – 1 – expm1() Method with Examples

`java.lang.Math.expm1()` method is used to find the e^x -1 of a double value in Java for the given input (`x` – parameter).
Note that for values of x near 0, the exact sum of expm1(x) + 1 is much closer to the true result of ex than exp(x).
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic. The result of expm1 for any finite input must be greater than or equal to -1.0. Note that once the exact result of ex – 1 is within 1/2 ulp of the limit value -1, -1.0 should be returned.

`expm1()` method exists in `Math` class of `java.lang` package.
Since: JDK1.5

## Declaration of `expm1()` Method

The declaration of `expm1()` method is:

## Syntax of `expm1()` Method

The syntax of `expm1()` method in Java is:

Example

Output:
` 8102.083927575384 `
Example
By importing `java.lang` package the syntax of `expm1()` method can be used as:

Output:
` 7.200489933638588E10 `

## Parameters of `expm1()` Method in Java

`x` – Where `x` is any valid double input value. This parameter is required.

## Error Handling

If the `x` parameter is not a number `expm1()` method returns an `error`.
If there is no argument (`x` – input value) passes to the method, the compiler will produce an `error`.Example

Output:
`Error`

## Return Value of `expm1()` Method in Java

`expm1()` method returns the computed value of e^x -1 of a double value for the given input (`x` – parameter).the value ex – 1.

## Java `expm1()` Method Example 1

Output:
` ex -1 of a Negative Value: -0.9999999936129925 ex -1 of a Positive Value: 1.1680887709814473E12 ex -1 of Zero: 0.0 `

## Java `expm1()` Method Example 2

Output:
` Infinity 4.9E-324 NaN -1.0 4.2867000000918794E-11 2.083198183463838E7 0.0 -0.9242259959771545 -1.0 `

## Special Cases of `expm1()` Method in Java

If the argument is NaN, the result is NaN.
If the argument is positive infinity, then the result is positive infinity.
If the argument is negative infinity, then the result is -1.0.
If the argument is zero, then the result is a zero with the same sign as the argument.
Example

Output:
` 0.0 0.0 Infinity -1.0 NaN `