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38 lines
851 B
Plaintext
38 lines
851 B
Plaintext
NAME
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atan2 - angle to point
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SYNOPSIS
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atan2(y, x, [,eps])
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TYPES
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y real
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x real
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eps nonzero real, defaults to epsilon()
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return real
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DESCRIPTION
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If x and y are not both zero, atan2(y, x, eps) returns, as a multiple of
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eps with error less than abs(eps), the angle t such that
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-pi < t <= pi and x = r * cos(t), y = r * sin(t), where
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r > 0. Usually the error does not exceed abs(eps)/2.
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Note that by convention, y is the first argument; if x > 0,
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atan2(y, x) = atan(y/x).
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To conform to the 4.3BSD ANSI/IEEE 754-1985 math lib, atan2(0,0)
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returns 0.
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EXAMPLE
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> print atan2(0,0), atan2(1,sqrt(3)), atan2(17,53,1e-100)
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0 ~.52359877559829887307 ~.31038740713235146535
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LIMITS
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none
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LIBRARY
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NUMBER *qatan2(NUMBER *y, *x, *acc)
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SEE ALSO
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acos, asin, atan, cos, epsilon, sin, tan
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