PHP 7.0.6 Released

    acos

    (PHP 4, PHP 5, PHP 7)

    acos — Arc cosine

    Description

    float acos ( float $arg )

    Returns the arc cosine of arg in radians. acos() is the complementary function of cos(), which means that a==cos(acos(a)) for every value of a that is within acos()' range.

    Parameters

    arg

    The argument to process

    Return Values

    The arc cosine of arg in radians.

    See Also

    User Contributed Notes

    zoltan dot szentesi at nokia dot com
    9 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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