Java - Math pow(double a, double b) method

Description

The Java Math pow(double a, double b) returns the value of the first argument raised to the power of the second argument. Special cases −

  • If the second argument is positive or negative zero, then the result is 1.0.

  • If the second argument is 1.0, then the result is the same as the first argument.

  • If the second argument is NaN, then the result is NaN.

  • If the first argument is NaN and the second argument is nonzero, then the result is NaN.

  • If

    • the absolute value of the first argument is greater than 1 and the second argument is positive infinity, or

    • the absolute value of the first argument is less than 1 and the second argument is negative infinity,

  • then the result is positive infinity.

  • If

    • the absolute value of the first argument is greater than 1 and the second argument is negative infinity, or

    • the absolute value of the first argument is less than 1 and the second argument is positive infinity,

  • then the result is positive zero.

  • If the absolute value of the first argument equals 1 and the second argument is infinite, then the result is NaN.

  • If

    • the first argument is positive zero and the second argument is greater than zero, or

    • the first argument is positive infinity and the second argument is less than zero,

  • then the result is positive zero.

  • If

    • the first argument is positive zero and the second argument is less than zero, or

    • the first argument is positive infinity and the second argument is greater than zero,

  • then the result is positive infinity.

  • If

    • the first argument is negative zero and the second argument is greater than zero but not a finite odd integer, or

    • the first argument is negative infinity and the second argument is less than zero but not a finite odd integer,

  • then the result is positive zero.

  • If

    • the first argument is negative zero and the second argument is a positive finite odd integer, or

    • the first argument is negative infinity and the second argument is a negative finite odd integer,

  • then the result is negative zero.

  • If

    • the first argument is negative zero and the second argument is less than zero but not a finite odd integer, or

    • the first argument is negative infinity and the second argument is greater than zero but not a finite odd integer,

  • then the result is positive infinity.

  • If

    • the first argument is negative zero and the second argument is a negative finite odd integer, or

    • the first argument is negative infinity and the second argument is a positive finite odd integer,

  • then the result is negative infinity.

  • If the first argument is finite and less than zero

    • if the second argument is a finite even integer, the result is equal to the result of raising the absolute value of the first argument to the power of the second argument

    • if the second argument is a finite odd integer, the result is equal to the negative of the result of raising the absolute value of the first argument to the power of the second argument

    • if the second argument is finite and not an integer, then the result is NaN.

  • If both arguments are integers, then the result is exactly equal to the mathematical result of raising the first argument to the power of the second argument if that result can in fact be represented exactly as a double value.

(In the foregoing descriptions, a floating-point value is considered to be an integer if and only if it is finite and a fixed point of the method ceil or, equivalently, a fixed point of the method floor. A value is a fixed point of a one-argument method if and only if the result of applying the method to the value is equal to the value.)

The computed result must be within 1 ULP of the exact result. Results must be semi-monotonic.

Declaration

Following is the declaration for java.lang.Math.pow() method

public static double pow(double a, double b)

Parameters

  • a − the base.

  • b − the exponent.

Return Value

This method returns the value ab.

Exception

NA

Example 1

The following example shows the usage of Math pow() method for positive values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = 2.0;
      double y = 5.4;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.pow(" + x + "," + y + ")=" + Math.pow(x, y));
      System.out.println("Math.pow(" + y + "," + x + ")=" + Math.pow(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.pow(2.0,5.4)=42.22425314473263
Math.pow(5.4,2.0)=29.160000000000004

Example 2

The following example shows the usage of Math pow() method for negative values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = -2.0;
      double y = -5.4;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.pow(" + x + "," + y + ")=" + Math.pow(x, y));
      System.out.println("Math.pow(" + y + "," + x + ")=" + Math.pow(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.pow(-2.0,-5.4)=NaN
Math.pow(-5.4,-2.0)=0.034293552812071325

Example 3

The following example shows the usage of Math pow() method for zero and one values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = 0.0;
      double y = 1.0;
   
      // print x raised by y and then y raised by x
      System.out.println("Math.pow(" + x + "," + y + ")=" + Math.pow(x, y));
      System.out.println("Math.pow(" + y + "," + x + ")=" + Math.pow(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.pow(0.0,1.0)=0.0
Math.pow(1.0,0.0)=1.0
java_lang_math.htm
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