Math function atan2() to return Arc tangent of two inputs in PHP

Find an angle from x and y coordinates

atan2() uses both coordinate components to determine the correct quadrant and returns the angle in radians. Convert the result with rad2deg() when you need degrees.

$y = 1;
$x = 1;
$angle = atan2($y, $x);
echo rad2deg($angle); // 45

The examples below build from the basic call to practical variations and edge cases.

<?Php
echo atan2(0,2); // Output is 0
echo "<br>";
echo atan2(1,3); // Output  0.32175055439664
echo "<br>";
echo atan2(-1,-3); // -2.8198420991932
echo "<br>";
echo atan2(4,2); // Output is 1.1071487177941
echo "<br>";
echo atan2(2,1); // Output is 1.1071487177941
echo "<br>";
echo atan2(90,180); // Output is 0.46364760900081
?>

atan2(float $y, float $x): float;

The first argument is the y-coordinate and the second is the x-coordinate. The return value is an angle in radians.

Example: Angle for Positive Coordinates

$x = 1;
$y = 1;
echo atan2($y, $x);  // Output: 0.78539816339745 (45 degrees in radians)

Example: Angle for Negative Coordinates

$x = -1;
$y = -1;
echo atan2($y, $x);  // Output: -2.3561944901923 (-135 degrees in radians)

Example: Angle for Horizontal Line

$x = 5;
$y = 0;
echo atan2($y, $x);  // Output: 0 (Horizontal line along the positive x-axis)

The function returns a result between -π and π.
These examples illustrate the use of `atan2()` to determine the angle for various coordinate positions.

Questions

What does the `atan2()` function in PHP do?
What is the purpose of the `atan2()` function in PHP?
How is the `atan2()` function used to calculate the arctangent of the quotient of two numbers?
What is the range of values returned by the `atan2()` function in PHP?
How does the `atan2()` function differ from the `atan()` function in PHP?
What are the parameters required by the `atan2()` function?
Can the `atan2()` function be used with both degrees and radians?
What happens if you pass invalid arguments to the `atan2()` function?
How can you use the `atan2()` function to calculate the angle in radians given the x and y coordinates?
What type of value does the `atan2()` function return: integer, float, or something else?

ATAN() function
Math Functions

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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atan2():the arc tangent of the quotient of its two arguments