Java - Math log(double) method

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Description

The Java Math log(double a) returns the natural logarithm (base e) of a double value. Special cases:

• If the argument is NaN or less than zero, then the result is NaN.

• If the argument is positive infinity, then the result is positive infinity.

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

Declaration

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

public static double log(double a)

Parameters

a − a value

Return Value

This method returns the value ln a, the natural logarithm of a.

Exception

NA

Example 1

The following example shows the usage of Math log() method.

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

      // get a double number
      double x = 10.7;

      // print the log of the number
      System.out.println("Math.log(" + x + ")=" + Math.log(x));
   }
}

Output

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

Math.log(10.7)=2.3702437414678603

Example 2

The following example shows the usage of Math log() method of zero value.

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

      // get a double number
      double x = 0.0;

      // print the log of the number
      System.out.println("Math.log(" + x + ")=" + Math.log(x));
   }
}

Output

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

Math.log(0.0)=-Infinity

Example 3

The following example shows the usage of Math log() method of a negative number.

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

      // get a double number
      double x = -10.7;

      // print the log of the number
      System.out.println("Math.log(" + x + ")=" + Math.log(x));
   }
}

Output

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

Math.log(-10.7)=NaN