# JavaScript Math cos()

The `cos()` method computes the trigonometric cosine of the specified angle and returns it.

### Example

``````// cosine of the angle 1
let value = Math.cos(1);
console.log(value);

// Output: 0.5403023058681398``````

## cos() Syntax

The syntax of the `Math.cos()` method is:

``Math.cos(angle)``

Here, `cos()` is a static method. Hence, we are accessing the method using the class name, `Math`.

## cos() Parameter

The `cos()` method takes a single parameter:

• `angle` - in radians whose cosine value is to be calculated

## cos() Return Value

The `cos()` method returns:

• cosine value of the given `angle` (in radians)
• NaN (Not a Number) for a non-numeric argument

## Example 1: JavaScript Math.cos()

``````// cosine of 5 radians
let value1 = Math.cos(5);
console.log(value1);

let value2 = Math.cos(-2);
console.log(value2);

// Output:
// 0.28366218546322625
// -0.4161468365471424``````

In the above example,

• `Math.cos(5)` - computes the cosine value of the angle 5
• `Math.cos(-2)` - computes the cosine value of the angle -2

## Example 2: Math.cos() with Math Constants

``````// math constants as arguments
let value3 = Math.cos(Math.PI);
console.log(value3);

// Output: -1``````

In the above example, we have used the `cos()` method to compute the cosine of the math constant `PI`.

## Example 3: Math.cos() with Non-Numeric argument

``````let string = "Darth Vader";

// cos() with string as argument
let value = Math.cos(string);
console.log(value);

// Output:
// NaN``````

In the above example, we have tried to calculate the cosine value of the string `"Darth Vader"` resulting in NaN as the output.

## Example 4: Math.cos() with Infinity

``````// infinity as argument
let value1 = Math.cos(Infinity);
console.log(value1);

// negative infinity as argument
let value2 = Math.cos(-Infinity);
console.log(value2);

// Output:
// NaN
// NaN``````

The `cos()` method doesn't treat infinity as a number so the method returns NaN with this argument.

Also, the cosine of an infinite angle is indefinite, which can't be defined with a number.