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JavaScript Math.atan2() Method

The Math.atan2() method in JavaScript is used to calculate the arctangent of the quotient of its arguments, representing the angle in radians. It takes two parameters, y and x, and calculates the angle between the positive x-axis and the point (x, y). The result will be in the range of π to π, or -180 degrees to 180 degrees.

Syntax

Following is the syntax of JavaScript Math.atan2() method −

Math.atan2(y, x)

Parameters

This method accepts only two parameters. The same are described below −

  • y: The vertical coordinate.
  • x: The horizontal coordinate.

Return value

This method returns a numeric value representing the angle in radians (between -π and π, inclusive) between the positive x-axis and the point (x, y).

Example 1

In the following example, we are using the JavaScript Math.atan2() method to calculate the arctangent of (1/1) −

<html>
<body>
<script>
   const result = Math.atan2(4, 1);
   document.write(result);
</script>
</body>
</html>

Output

If we execute the above progran, it returns approximately "0.7853" (45 degrees in radians).

Example 2

In this example, since the y parameter is 0, the resulting angle will be 0 −

<html>
<body>
<script>
   const result = Math.atan2(0, 1);
   document.write(result);
</script>
</body>
</html>

Output

As we can see in the output, it returned 0 as result.

Example 3

If we use atan2() method with Infinity, the result will still be in between -π and π −

<html>
<body>
<script>
   const result1 = Math.atan2(Infinity, 0);
   const result2 = Math.atan2(-Infinity, 0);
   const result3 = Math.atan2(Infinity, -Infinity);
   document.write(result1, "<br>", result2, <br>", result3);
</script>
</body>
</html>

Output

As we can see in the output, it returned result is in between -π and π.

Example 4

If we pass string arguments to atan2() method, the result will be "NaN" −

<html>
<body>
<script>
   const result = Math.atan2("Tutorialspoint", "Tutorix");
   document.write(result);
</script>
</body>
</html>

Output

As we can see in the output, it returned NaN as result.