java.lang.Math.atan(double a)

package com.codingdict;



import java.lang.*;



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));

   }

}