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# acos

(PHP 4, PHP 5)

acosArco coseno

### Descrizione

float acos ( float `\$arg` )

Restituisce l'arco coseno di `arg` in radianti. La funzione acos() รจ complementare alla funzione cos(), ovvero che a==cos(acos(a)) per ciascun valore di a nel range di acos().

Vedere anche: acosh(), asin() e atan().

``` With this function you can get the number PI.This is done like this: acos(-1) === M_PI ```
``` 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! :-) ```