# 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:

## Syntax of `cos()` Method

The syntax of `cos()` method in Java is:

## Example for Syntax of `cos()` Method

Output:
`0.7071067811865476`

## Another example for Syntax of `cos()` Method

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

Output:
`0.7071067811865476`

## Special Cases of `cos()` Method in Java

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

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

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

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

Output:
` -1.0 -0.9117339147869651 1.0 NaN -0.5550380793155483 1.0 -0.41392320157395335 1.0 -0.8464080412157756 -0.4202728158729685 `