Java Math expm1()

The Java Math expm1() method returns the Euler's number e raised to the power of the specified value minus 1.

That is, Math.expm1(4.0) = e4.0-1. Also in mathematics, Math.expm1(x) = ex-1.

The syntax of the expm1() method is:

Math.expm1(double a)

Note: The expm1() method is a static method. Hence, we can call the method directly using the class name Math.


expm1() Parameters

  • a - number to be raised as power of e

expm1() Return Values

  • returns ea-1 for the argument a

Note: Here, e is the Euler's number whose value is 2.71828


Example: Java Math.expm1()

class Main {
  public static void main(String[] args) {

    // Math.expm1() method
    double a = 4.0d;
    System.out.println(Math.expm1(a));  // 53.598150033144236

    // without using Math.expm1()
    // value of Euler Number
    double euler = 2.71828d;
    System.out.println(Math.pow(euler, a)-1);  // 53.5980031309658

  }
}

In the above example, we have used the Math.pow() method to compute the e4.0 value. Here, we can see that

Math.expm1(4.0) = e4.0-1