Java - Math atan(double) Method

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Description

The Java Math atan(double a) returns the arc tangent of an angle, in the range of -pi/2 through pi/2. Special cases −

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

• If the argument is zero, then the result is a zero with the same sign as the argument.

A result must be within 1 ulp of the correctly rounded result. Results must be semi-monotonic.

Declaration

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

public static double atan(double a)

Parameters

a − the value whose arc tangent is to be returned.

Return Value

This method returns the arc tangent of the argument.

Exception

NA

Getting Arc Tangent of an Angle Example

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

package com.tutorialspoint;

public class MathDemo {

   public static void main(String[] args) {

      // get a variable x which is equal to PI/2
      double x = Math.PI / 2;

      // convert x to radians
      x = Math.toRadians(x);

      // get the arc tangent of x
      System.out.println("Math.atan(" + x + ")=" + Math.atan(x));
   }
}

Output

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

Math.atan(0.027415567780803774)=0.0274087022410345

Getting Arc Tangent of a 0° Angle Example

The following example shows the usage of Math atan() method of 0° angle.

package com.tutorialspoint;

public class MathDemo {

   public static void main(String[] args) {

      // get a variable x which is equal to zero
      double x = 0.0d;

      // convert x to radians
      x = Math.toRadians(x);

      // get the arc tangent of x
      System.out.println("Math.atan(" + x + ")=" + Math.tan(x));
   }
}

Output

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

Math.atan(0.0)=0.0

Getting Arc Tangent of a 45° Angle Example

The following example shows the usage of Math atan() method of 45° angle.

package com.tutorialspoint;

public class MathDemo {

   public static void main(String[] args) {

      // get a variable x which is equal to zero
      double x = 45.0d;

      // convert x to radians
      x = Math.toRadians(x);

      // get the arc tangent of x
      System.out.println("Math.atan(" + x + ")=" + Math.tan(x));
   }
}

Output

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

Math.atan(0.7853981633974483)=0.9999999999999999