Java Math.atan() method

The java.lang.Math.atan() is used to calculate the trigonometric Arc Tangent of an angle. Arc Tangent is also called as inverse of a tangent. This method returns the values between -pi/2 and pi/2.

Syntax

Parameter

Return

If the argument is positive or negative number, this method will return the Arc Tangent value.
If the argument is NaN, this method will return NaN.
If the argument is Zero, this method will return Zero with the same sign as the argument.

Example 1

public class AtanExample1
{
    public static void main(String[] args) 
    {
        double a = 6.267;
        System.out.println(Math.atan(a));
    }
}

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Output:

1.4125642791467878

Example 2

public class AtanExample2
{
    public static void main(String[] args) 
    {
        double a = -1.0;
        System.out.println(Math.atan(a));
    }
}

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Output:

-0.7853981633974483

Example 3

public class AtanExample3
{
    public static void main(String[] args) 
    {
        double a = 0.0;
        // Input positive zero, Output positive zero
        System.out.println(Math.atan(a));
    }
}

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Output:

0.0

Example 4

public class AtanExample4
{
    public static void main(String[] args) 
    {
        double a = Math.PI;
        System.out.println(Math.atan(a));
    }
}

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Output:

1.2626272556789115

Example 5

public class AtanExample5
{
    public static void main(String[] args) 
    {
        double a = 0.0/0;
        // Input NaN, Output NaN
        System.out.println(Math.atan(a));
    }
}

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Output: