(PHP 4, PHP 5, PHP 7)



acos ( float $arg ) : float

Возвращает арккосинус числа arg в радианах. acos() - обратная тригонометрическая функция к cos(), то есть a==cos(acos(a)) для каждого значения а, входящего в область значений функции acos().

Список параметров


Аргумент функции

Возвращаемые значения

Арккосинус числа arg в радианах.

Смотрите также

  • cos() - Косинус
  • acosh() - Гиперболический арккосинус
  • asin() - Арксинус
  • atan() - Арктангенс

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User Contributed Notes 2 notes

nurlanovic at gmail dot com
1 year ago
With this function you can get the number PI.
This is done like this: acos(-1) === M_PI
zoltan dot szentesi at nokia dot com
12 years ago
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! :-)
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