StrictMath log() Method In Java

The Java.lang.StrictMath.log() is an inbuilt method of StrictMath class which is used to calculate the natural logarithm i.e., log with base e, of a given double value. It gives rise to three special results: 

• It returns a positive infinity when the argument is positive infinity.
• It returns NaN when the argument is NaN or less than zero.
• The result is negative infinity when the argument is positive zero or negative zero.

Syntax:

public static double log(double num)

Parameters: The method accepts one parameter num of double type whose logarithmic value is to be found.
Return Value: The method returns the value of natural logarithm of num.
Examples :

Input: num = 5.0 
Output: 1.6094379124341003

Input: num = 10.0 
Output:  2.302585092994046

Below programs illustrate the Java.lang.StrictMath.log() Method: 
Program 1: 

java

// Java program to illustrate the
// Java.lang.StrictMath.log() Method
import java.lang.*;

public class Geeks {

public static void main(String[] args) {

    double num1 = 10 , num2 = 25.2 ;

    // It returns natural logarithm(base e)
    double log_Value = StrictMath.log(num1);
    System.out.print("Log value of " + num1 + " = " );
    System.out.println(log_Value);

    log_Value = StrictMath.log(num2);
    System.out.print("Log value of " + num2 + " = " );
    System.out.println(log_Value);

}
}

Output:

Log value of 10.0 = 2.302585092994046
Log value of 25.2 = 3.2268439945173775

Program 2: 

java

// Java program to illustrate the
// Java.lang.StrictMath.log() Method
import java.lang.*;

public class Geeks {

public static void main(String[] args) {

    double num1 = 0 , num2 = (1.0/0.0) , num3 = 1;

    // It returns natural logarithm(base e)
    double log_Value = StrictMath.log(num1);
    System.out.print("Log value of " + num1 + " = " );
    System.out.println(log_Value);

    log_Value = StrictMath.log(num2);
    System.out.print("Log value of " + num2 + " = " );
    System.out.println(log_Value);

    log_Value = StrictMath.log(num3);
    System.out.print("Log value of " + num3 + " = " );
    System.out.println(log_Value);

}
}

Output:

Log value of 0.0 = -Infinity
Log value of Infinity = Infinity
Log value of 1.0 = 0.0