JavaScript Math.atan() Method

Quiz

The JavaScript Math.atan() method accepts a number as a parameter and calculates the arctangent (inverse of tangent) of a number. The result is the angle (in radians) whose tangent is the specified number.

Here are different scenarios illustrating the behavior of the Math.atan() method −

If the argument provided to this method is a numeric value, it returns the angle in radians between -/2 and /2.
If the argument is "Inifinity", it returns /2.
If it is "-Infinity", it returns -/2.
If the argument is non-numeric or empty number, it returns "NaN" (Not a Number) as the result.

Syntax

Following is the syntax of JavaScript Math.atan() method −

Math.atan(x);

Parameters

This method accepts only one parameter. The same is described below −

x: A number representing the tangent of an angle.

Return value

This method returns the arctangent (inverse of tangent) of the provided number in "radians".

Example 1

In the following example, we are demonstrating the basic usage of JavaScript Math.atan() method −

<html>
<body>
<script>
   let number1 = Math.atan(-2);
   document.write(number1, "<br>");

   let number2 = Math.atan(0);
   document.write(number2, "<br>");

   let number3 = Math.atan(2);
   document.write(number3);
</script>
</body>
</html>

Output

It returns the arctangent (in radians) for the provided arguments.

Example 2

Here, we are calculating the arctangent of Infinity −

<html>
<body>
<script>
   let number1 = Math.atan(Infinity);
   document.write(number1, "<br>");

   let number2 = Math.atan(-Infinity);
   document.write(number2);
</script>
</body>
</html>

Output

As we can see, it returns /2 for "Infinity" and -/2 for "-Infinity".

Example 3

If we pass an empty number or non-numeric value as an argument to this method, it returns "NaN" as output −

<html>
<body>
<script>
   let number1 = Math.atan("Tutorialspoint");
   let number2 = Math.atan();

   document.write(number1, "<br>", number2);
</script>
</body>
</html>

Output

If we execute the above program, it returns "NaN" as result.

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