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

<?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);

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)

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