Java – Find Trigonometric Cosine – cos() Method with Examples

java.lang.Math.cos() method is used to find the trigonometric cosine of an angle of a double value in Java, (an angle must be in radians), for the given input (x – parameter).
Note: The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

 

cos() method exists in Math class of java.lang package.
Since: JDK1.0

 

Declaration of cos() Method

The declaration of cos() method is:

public static double cos(double x)

 

Syntax of cos() Method

The syntax of cos() method in Java is:

 
java.lang.Math.cos(double x)

Example for Syntax of cos() Method

/*
*Find the trigonometric cosine of an angle of given input(double) without importing the 
java.lang Package.
*/
public class JavaMathExample {
   public static void main(String[] args) {
        //Declaring variables
        double degree = 45;
        // convert given angle to radian
        double radians;
        radians = Math.toRadians(degree);
        double result;
        //Assign trigonometric cosine of an angle of radian to result variable
        result = java.lang.Math.cos(radians);
        //Printing result to the console
        System.out.println(result);
    }
}

Output:
0.7071067811865476

Another example for Syntax of cos() Method

By importing java.lang package the syntax of cos() method can be used as:

/*
*Find the trigonometric cosine of an angle 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 degree = 45;
        // convert given angle to radian
        double radians;
        radians = Math.toRadians(degree);
        double result;
        //Assign trigonometric cosine of an angle of radian to result variable
        result = Math.cos(radians);
        //Printing result to the console
        System.out.println(result);
    }
}

Output:
0.7071067811865476

 

Special Cases of cos() Method in Java

If the argument is NaN or an infinity, then the result is NaN.
Example

/*
*This example shows some special cases of cos() method in Java
*/
import java.lang.*; //importing java.lang package

public class JavaMathExample {
    public static void main(String[] args) {

        double positiveInfinity = Double.POSITIVE_INFINITY;
        double negativeInfinity = Double.NEGATIVE_INFINITY;
        double nan = Double.NaN;
        double result;
        

        //Here argument is positive infinity, output will also be NaN
        result = Math.cos(positiveInfinity);
        System.out.println(result);

        //Here argument is negative infinity, output will be NaN
        result = Math.cos(negativeInfinity);
        System.out.println(result);

        //Here argument is NaN, output will be NaN
        result = Math.cos(nan);
        System.out.println(result);

    }

}

Output:

NaN
NaN
NaN

 

Parameters of cos() Method in Java

x – Where x is any valid double input value. This parameter is required.

 

Error Handling

If the x parameter is not a number cos() 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.cos(x);
        System.out.println(result);

        //Here no argument is used
        result = Math.cos();
        System.out.println(result);


    }

}

Output:
Error

 

Return Value of cos() Method in Java

cos() method returns the trigonometric cosine of an angle of a double value for the given input (x – parameter).

 

Java cos() Method Example 1

import java.lang.*; //importing java.lang package

public class JavaMathExample {
    public static void main(String[] args) {
        double value1 = Math.toRadians(Math.PI);
        double value2 = Math.toRadians(75);
        double value3 = Math.toRadians(0);
        System.out.println("The value of trigonometric cosine is: "+Math.cos( value1));
        System.out.println("The value of trigonometric cosine is: "+Math.cos(value2));
        System.out.println("The value of trigonometric cosine is: "+Math.cos(value3));

    }
}

Output:

The value of trigonometric cosine is: 0.9984971498638638
The value of trigonometric cosine is: 0.25881904510252074
The value of trigonometric cosine is: 1.0

 

Java cos() 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 [] = { Math.PI,Math.E, Double.MIN_VALUE,
                Double.NaN, Double.MIN_EXPONENT, 42.867e-12, 16.852, 0, -2.58, -78.8569e7 };

        //Use for loop to print trigonometric cosine of an angle of each element of the array

        for (int i = 0;i < test.length ; i++){
            System.out.println(  Math.cos(test[i])  );
        }
   }
}

Output:

-1.0
-0.9117339147869651
1.0
NaN
-0.5550380793155483
1.0
-0.41392320157395335
1.0
-0.8464080412157756
-0.4202728158729685