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 — Арккосинус
Описание
float acos
( float
$arg
)
Возвращает арккосинус числа arg в радианах.
acos() - обратная тригонометрическая функция к
cos(), т.е.
a==cos(acos(a)) для каждого значения а, входящего в область значений функции
acos().
Список параметров
-
arg -
Аргумент функции
Возвращаемые значения
Арккосинус числа arg в радианах.
add a note
User Contributed Notes
acos - [2 notes]
zoltan dot szentesi at nokia dot com ¶
6 years ago
anthony at interiorgoodsdirect dot com ¶
5 years ago
To calculate an angle from a triangle's sides.
Use the 'law of cosines' :
<?php
// a²+b²-c²
// cosC = --------
// 2ab
function calculateAngle($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.