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    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 inverse 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

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    User Contributed Notes 2 notes

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