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calc/help/aversin
Landon Curt Noll 3abedd6713 fix aversin() and acoversin()
In cases where the real value to the inverse versed sine and the
inverse coversed sine function produces a complex value, the
conversion from real to complex was incorrect.

Added c_to_q(COMPLEX *c, bool cfree) to make is easier to convert
a COMPLEX value that is real (imag part is 0) into a NUMBER and
optionally free the COMPLEX value.

The func.c code now uses c_to_q().

NOTE: There is a XXX bug marked in the f_aversin() and f_acoversin()
that still needs to be fixed.
2023-09-05 16:09:22 -07:00

65 lines
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NAME
aversin - inverse versed trigonometric sine
SYNOPSIS
aversin(x [,eps])
TYPES
x number (real or complex)
eps 0 < real < 1, defaults to epsilon()
return real
DESCRIPTION
Returns the inverse versed sine of x to a multiple of eps with error less in
absolute value than .75 * eps.
The inverse versed sine function is sometimes called avers, sometimes called aver,
may be defined as:
aversin(x) = acos(1 - x)
EXAMPLE
; print aversin(.5, 1e-5), aversin(.5, 1e-10), aversin(.5, 1e-15), aversin(.5, 1e-20)
1.0472 1.0471975512 1.047197551196598 1.04719755119659774615
; print aversin(0), aversin(-5), aversin(2 + 3i)
0 2.47788873028847500485i 1.87839997632560786916+1.86416154415788242831i
LIMITS
0 < eps < 1
LINK LIBRARY
NUMBER *qaversin_or_NULL(NUMBER *q, NUMBER *epsilon);
NUMBER *qaversin(NUMBER *q, NUMBER *epsilon);
COMPLEX *c_aversin(COMPLEX *c, NUMBER *epsilon);
SEE ALSO
sin, cos, tan, cot, sec, csc
asin, acos, atan, acot, asec, acsc
versin, coversin
acoversin
epsilon
## Copyright (C) 2023 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
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##
## Under source code control: 2023/09/03 00:26:24
## File existed as early as: 2023
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/