 # JavaScript Math atan()

The `atan()` method calculates the arctangent (inverse of tangent) of the specified angle and returns it.

### Example

``````let num = Math.atan(1);
console.log(num);
//Output: 0.7853981633974483``````

## atan() Syntax

The syntax of the `atan()` method is:

``Math.atan(angle)``

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

## atan() Parameter

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

• `angle` - in radians whose arctangent value is calculated

## atan() Return Value

The `atan()` method returns:

• arctangent value of the `angle` argument
• NaN (Not a Number) if `x` is a non-numeric value

Note: The returned angle will always be in the range `-π/2` to `π/2` for numeric arguments.

## Example 1: JavaScript Math.atan()

``````// compute arctangent of 0
let number1 = Math.atan(0);
console.log(number1);

// compute arctangent of -5
let number2 = Math.atan(-5);
console.log(number2);

// Output:
// 0
// -1.373400766945016``````

In the above example,

• `Math.atan(0)` - calculates the arctangent of `0`
• `Math.atan(-5)` - calculates the arctangent of `-5`

## Example 2: Math.atan() with Infinity

``````// atan() with positive infinity
let number1 = Math.atan(Infinity);
console.log(number1);

// atan() with negative infinity
let number2 = Math.atan(-Infinity);
console.log(number2);

// Output:
// 1.5707963267948966 (π/2)
// -1.5707963267948966 (-π/2)``````

Here the `math.atan()` method calculates the arctangent of infinity. As you can see, the output value is still between -π/2 and π/2.

## Example 3: Math.atan() with a Non-Numeric Argument

``````// string variables
let string = "Dwayne"

// atan() with string arguments
let result = Math.atan(string);
console.log(result);

// Output: NaN``````

In the program above, we have used a string argument, `Dwayne` with `atan()`. In this case, we get NaN as output.