java.lang.Math.atan()
method is used to find the arc tangent of a double value for the given input (x
– parameter) in Java.
he returned angle is in the range -pi/2 through pi/2.
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
Package
atan()
method exists in Math
class of java.lang
package.Since: JDK1.0
Method Declaration of atan()
Method
The declaration of
atan()
method is:
public static double atan(double x)
Syntax of atan()
Method
The syntax of
atan()
method in Java is:
java.lang.Math.atan(double x)
Example
/* *Find the arc tangent of given input(double) without importing the java.lang Package. */ public class JavaMathExample { public static void main(String[] args) { //Declaring variables double x = -4876.1874; double result; //Assign arc tangent of x to result variable result = java.lang.Math.atan(x); //Printing result to the console System.out.println(result); } }
Output:
Example
By importing java.lang
package the syntax of atan()
method can be used as:
/* *Find the arc tangent of given input(double) by importing the java.lang Package. */ import java.lang.*; //importing package public class JavaMathExample { public static void main(String[] args) { //Declaring variables double x = -68.97; double result; //Assign arc tangent of x to result variable result = Math.atan(x); //Printing result to the console System.out.println(result); } }
Output:
Special Cases of atan()
Method in Java
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.
Example
If the argument is zero, then the result is a zero with the same sign as the argument.
Example
/* *This example shows some special cases of atan() method in Java */ import java.lang.*; //importing java.lang package public class JavaMathExample { public static void main(String[] args) { //Declaring variables double positiveZero = 0; double negativeZero = -0; double positiveInfinity = Double.POSITIVE_INFINITY; double negativeInfinity = Double.NEGATIVE_INFINITY; double nan = Double.NaN; double result; //Here argument is positive zero, output will also be positive zero result = Math.atan(positiveZero); System.out.println(result); //Here argument is negative zero, output will be positive zero result = Math.atan(negativeZero); System.out.println(result); //Here argument is positive infinity, output will also be positive infinity result = Math.atan(positiveInfinity); System.out.println(result); //Here argument is negative infinity, output will be negative infinity result = Math.atan(negativeInfinity); System.out.println(result); //Here argument is NaN, output will be NaN result = Math.atan(nan); System.out.println(result); } }
Output:
Parameters of atan()
Method in Java
x
– Where x
is any valid double input value. This parameter is required.
Error Handling
If the
If there is no argument (
x
parameter is not a number atan()
method returns an error
.If there is no argument (
x
– input value) passes to the method, the compiler will produce an error
.Example
/* *This example returns a compile time error */ import java.lang.*; //importing java.lang package public class JavaMathExample { public static void main(String[] args) { //Declaring variables String x = "Not a number"; double result; //argument is not a number result = Math.atan(x); System.out.println(result); //Here no argument is used result = Math.atan(); System.out.println(result); } }
Output:
Error
Return Value of atan()
Method in Java
atan()
method returns the arc tangent of a double value for the given input (x
– parameter).
Java atan()
Method Example 1
import java.lang.*; //importing java.lang package public class JavaMathExample { public static void main(String[] args) { double negativeValue = -18.869; double positiveValue = 27.78639; double zero = 0; System.out.println("arc tangent of a Negative Value: "+Math.atan(negativeValue)); System.out.println("arc tangent of a Positive Value: "+Math.atan(positiveValue)); System.out.println("arc tangent of Zero: "+Math.atan(zero)); } }
Output:
Java atan()
Method Example 2
import java.lang.*; //importing java.lang package public class JavaMathExample { public static void main(String[] args) { //Declare and initialize an array containing double values double test [] = { Double.MAX_VALUE, Double.MIN_VALUE, Double.NaN, Double.MIN_EXPONENT, 42.867e-12, 16.852, 0, -2.58, -78.8569e7 }; //Use for loop to print arc tangent of each element of the array for (int i=0; i < test.length; i++) { System.out.println( Math.atan(test[i]) ); } } }
Output: