JavaScript Math atan2()

atan2() Syntax

The syntax of the atan2() method is:

Math.atan2(x, y)

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

atan2() Parameters

The atan2() method takes two parameters:

• x - number, which is divided by the parameter y
• y - number that divides the parameter x

Here, the method computes the arctangent of x / y.

atan2() Return Value

The method returns:

• angle (in radians) after computing the arctan of x / y
• NaN (Not a Number) for non-numeric arguments x and y

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

Example 1: JavaScript Math.atan2()

In the above example,

• Math.atan2(5, 2) - computes the arctan of 2.5 ( 5 / 2 )
• Math.atan2(0, 5) - computes the arctan of 0 ( 0 / 5 )

Example 2: Math.atan2() with Infinity

Here, you can see we have successfully used the atan2() method with infinity. And the result is still between -π and π even though we have used it with infinity.

Example 3: Math.atan2() with Non-Numeric Arguments

The code above shows the use of the atan2() method with string arguments. That's why we get NaN as output.

Recommended readings:

• JavaScript Math tan()
• JavaScript Math atan()