NAME
    atan2 - angle to point

SYNOPSIS
    atan2(y, x, [,acc])

TYPES
    y		real
    x		real
    acc		real

    return	real

DESCRIPTION
    Return the angle which is determined by the point (x,y).  This
    function computes the arctangent of y/x in the range [-pi, pi].
    The value acc specifies the accuracy of the result.  By default, acc
    is epsilon().

    Note that by convention, y is the first argument.

    To conform to the 4.3BSD ANSI/IEEE 754-1985 math lib, atan2(0,0) is
    defined to return 0.

EXAMPLE
    > print atan2(0,0), atan2(1,sqrt(3)), atan2(17,53,1e-100)
    0 ~.52359877559829887307 ~.31038740713235146535

LIMITS
    acc > 0

LIBRARY
    NUMBER *qatan2(NUMBER *y, *x, *acc)

SEE ALSO
    acos, asin, atan, cos, epsilon, sin, tan
