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# acos

(PHP 4, PHP 5, PHP 7)

acosArco coseno

### Descripción

float acos ( float \$arg )

Devuelve el arco coseno de arg en radianes. acos() es la función complementaria de cos(), lo que quiere decir que a==cos(acos(a)) para cada valor de a en el rango de acos()'.

### Parámetros

arg

El argumento a procesar

### Valores devueltos

The arc cosine of arg in radians.

### User Contributed Notes 2 notes

nurlanovic at gmail dot com
2 months ago
With this function you can get the number PI.
This is done like this: acos(-1) === M_PI
-21
zoltan dot szentesi at nokia dot com
11 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! :-)