Java Math.log() method

The java.lang.Math.log() is used to find out the Logarithmic Value of any number. This method returns the natural logarithm (base e) of a double value as a parameter.

Syntax

Parameter

Return

If the argument is Positive value, this method will return the logarithm of a given value.
If the argument is Negative value, this method will return NaN.
If the argument is not a number (NaN), this method will return NaN.
If the argument is Positive Infinity, this method will return Positive Infinity.
If the argument is positive or negative Zero, this method will return Negative Infinity.

Example 1

public class LogExample1
{
    public static void main(String[] args) 
    {
        double x = 38.9;
        // Input positive double, output logarithm of x  
        System.out.println(Math.log(x));
    }
}

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Output:

3.6609942506244004

Example 2

public class LogExample2
{
    public static void main(String[] args) 
    {
        double x = -70.4;
        // Input negative double, output NaN  
        System.out.println(Math.log(x));
    }
}

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Output:

NaN

Example 3

public class LogExample3
{
    public static void main(String[] args) 
    {
        double x = 1.0/0;
        // Input positive infinity, output Infinity
        System.out.println(Math.log(x));
    }
}

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Output:

Infinity

Example 4

public class LogExample4
{
    public static void main(String[] args) 
    {
        double x = 0;
        // Input positive zero, output -Infinity
        System.out.println(Math.log(x));
    }
}

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Output: