abs
Wondering what is the use of 'acos' function?
It is essential in games, animations and drawings to determine the location of two objects relating to each other.
To the point: the angle of two vectors is calculated by
v1X*v2X + v1Y*v2Y
acos(--------------------------)=angle between two vectors.
|v1| * |v2|
|v1| and |v2| are the length of the vectors and calculated using Pithagoras-formula: |v1|=sqrt(v1X*v1X + v1Y*v1Y)
This helped me to calculate and share given space for 'n' amount of objects so that they don't overlap.
Enjoy! :-)
acos
(PHP 4, PHP 5)
acos — Arc cosinus
Description
float acos
( float
$arg
)
Retourne l'arc cosinus de arg
(arg en radians).
acos() est la fonction inverse de
cos(), ce qui signifie que
a==cos(acos(a)) pour toute valeur qui soit
dans l'intervalle de validité de acos().
Liste de paramètres
-
arg -
L'argument à traiter
Valeurs de retour
L'arc cosinus de arg, en radians.
add a note
User Contributed Notes
acos - [2 notes]
zoltan dot szentesi at nokia dot com ¶
6 years ago
anthony at interiorgoodsdirect dot com ¶
5 years ago
To calculate an angle from a triangle's sides.
Use the 'law of cosines' :
<?php
// a²+b²-c²
// cosC = --------
// 2ab
function calculateAngle($c,$a,$b)
{
$angleInRadians=acos((pow($a,2) + pow($b,2) - pow($c,2)) / (2 * $a * $b));
return rad2deg($angleInRadians);
}
?>
$a, $b, $c are the triangle sides.
The function returns the angle opposite side c, in degrees.