# Java Math Class static double expm1(double d) with example

Java Math Class static double expm1(double d) method: Here, we are going to learn about the static double expm1(double d) method of Math Class with its syntax and example.
Submitted by Preeti Jain, on August 22, 2019

## Math Class static double expm1(double d)

• This method is available in java.lang package.
• This method is used to return [ the exponential of the given number – 1] in the method or in other words it is used to calculate the ( e raised to the power of the given argument – 1).
• In this method, expm stands for exponentiation.
• This is a static method so this method is accessible with the class name too.
• The return type of this method is double that means it returns (The exponentiation of the given argument -1) and the argument and return value are of double type.
• In this method we pass only one parameter as an argument in the method of Math class and the given parameter is the exponent to raise the power of e -1.
• This method does not throw any exception.

Syntax:

```    public static double expm1(double d){
}
```

Parameter(s):

double d – A double value whose exponential to be found..

Note:

• If we pass "NaN" to the function, it returns the "NaN".
• If we pass positive infinity, it returns the positive infinity.
• If we pass negative infinity, it returns -1.0.
• If we pass zero (-0 or 0), it returns 0.0.

Return value:

The return type of this method is double, it returns the exponentiation of the given value.

### Java program to demonstrate example of expm1(double d) method

```// Java program to demonstrate the example of expm1(double d)
// method of Math Class

public class Expm1Method {
public static void main(String[] args) {
// Here we are declaring few variables
double d1 = 7.0 / 0.0;
double d2 = -7.0 / 0.0;
double d3 = 0.0;
double d4 = -0.0;
double d5 = 0.8;
double d6 = 2;

// Display previous value of d1,d2,d3, d4,d5 and d6
System.out.println(" Before implementing expm1() so the value of d1 is :" + d1);
System.out.println(" Before implementing expm1() so the value of d2 is :" + d2);
System.out.println(" Before implementing expm1() so the value of d3 is :" + d3);
System.out.println(" Before implementing expm1() so the value of d4 is :" + d4);
System.out.println(" Before implementing expm1() so the value of d5 is :" + d5);
System.out.println(" Before implementing expm1() so the value of d6 is :" + d6);

// Here , we will get (Infinity) because we are passing parameter
// whose value is (infinity)
System.out.println("After implementing expm1() so the value of d1 is :" + Math.expm1(d1));

// Here , we will get (-1.0) because we are passing parameter
// whose value is (-infinity)
System.out.println("After implementing expm1() so the value of d2 is :" + Math.expm1(d2));

// Here , we will get (0.0) because we are passing parameter
// whose value is (0.0)
System.out.println("After implementing expm1() so the value of d3 is :" + Math.expm1(d3));

// Here , we will get (-0.0) because we are passing parameter
// whose value is (-0.0)
System.out.println("After implementing expm1() so the value of d4 is :" + Math.expm1(d4));

// Here , we will get [(e raised to the power of 0.8) - 1]
// because we are passing parameter whose value is (0.8)
System.out.println("After implementing expm1() so the value of d5 is :" + Math.expm1(d5));

// Here , we will get [(e raised to the power of 2) - 1]
// because we are passing parameter whose value is (2)
System.out.println("After implementing expm1() so the value of d6 is :" + Math.expm1(d6));
}
}
```

Output

```E:\Programs>javac Expm1Method.java

E:\Programs>java Expm1Method
Before implementing expm1() so the value of d1 is :Infinity
Before implementing expm1() so the value of d2 is :-Infinity
Before implementing expm1() so the value of d3 is :0.0
Before implementing expm1() so the value of d4 is :-0.0
Before implementing expm1() so the value of d5 is :0.8
Before implementing expm1() so the value of d6 is :2.0

After implementing expm1() so the value of d1 is :Infinity
After implementing expm1() so the value of d2 is :-1.0
After implementing expm1() so the value of d3 is :0.0
After implementing expm1() so the value of d4 is :-0.0
After implementing expm1() so the value of d5 is :1.2255409284924677
After implementing expm1() so the value of d6 is :6.38905609893065
```