atan2 — Returns the arctangent based on an X-Y
float x: X-axis value of
float y: Y-axis value of
Arctangent as a float
This function returns the value of the arctangent of the
point denoted by the x and
y parameters. The return value
is in radians, in the range -pi to pi
(approximately -3.14 to 3.14).
PHP 3 since 3.0.5, PHP 4
Example 664. Calculate the
arctangent of a coordinate
$tanx = -1;
$tany = 1;
echo "The arctangent of $tanx/$tany is ", atan2($tanx, $tany);
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing
(Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch).
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