Files
calc/help/asec
Landon Curt Noll 42129a3672 change error printing from errnum to errsym
When printing an error, calc used to print the errnum (error number):

    ; 1/0
	    Error 10001

Calc now prints the errsym (errsym):

    ; 1/0
	    Error E_DIVBYZERO

Added errsym E_LN_3 for ln(0).
Added errsym E_LOG_5 for log(0).
Added errsym E_LOG2_4 for log2(0).
Added errsym E_LOGN_6 for logn(0,base).
2023-10-03 22:12:14 -07:00

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NAME
asec - inverse trigonometric secant
SYNOPSIS
asec(x [,eps])
TYPES
x number (real or complex)
eps 0 < real < 1, defaults to epsilon()
return real
DESCRIPTION
Returns the inverse trigonometric secant of x to a multiple of eps with error less in
absolute value than .75 * eps.
This function is sometimes called arcsec.
EXAMPLE
; print asec(0), asec(0.5), asec(1)
Error E_ASEC_3 1.31695789692481670863i 0
; print asec(-0.5), asec(-1)
3.14159265358979323846-1.31695789692481670863i 3.14159265358979323846
; print asec(.5, 1e-5), asec(.5, 1e-10), asec(.5, 1e-15), asec(.5, 1e-20)
1.31695i 1.316957897i 1.316957896924816i 1.31695789692481670863i
; print asec(5), asec(5i)
1.36943840600456582778 1.57079632679489661923+0.19869011034924140647i
; print asec(5+5i)
1.4711326239351014592+0.10033029811220500594i
; pi = pi(1e-20)
; print asec(pi/6), asec(pi/3)
1.26327680856656556836i 0.30137360974529145454
; print asec(4*pi/3)
1.32973601406082299099
LIMITS
0 < eps < 1
LINK LIBRARY
NUMBER *qasec(NUMBER *x, NUMBER *eps)
COMPLEX *c_asec(COMPLEX *c, NUMBER *epsilon)
SEE ALSO
sin, cos, tan, cot, sec, csc
asin, acos, atan, acot, acsc
versin, coversin, vercos, covercos
aversin, acoversin, avercos, acovercos
haversin, hacoversin, havercos, hacovercos
ahaversin, hacoversin, havercos, ahacovercos
exsec, aexsec, excsc, aexcsc
crd, acrd
cas, cis
epsilon
EXTERNAL RESOURCES
For general information on trigonometric functions, see:
https://en.wikipedia.org/wiki/Trigonometric_functions#Unit-circle_definitions
https://en.wikipedia.org/wiki/Versine
https://en.wikipedia.org/wiki/Exsecant
https://en.wikipedia.org/wiki/Inverse_trigonometric_functions
https://en.wikipedia.org/wiki/Chord_(geometry)
https://en.wikipedia.org/wiki/Secant_line
https://en.wikipedia.org/wiki/Hartley_transform#cas
https://en.wikipedia.org/wiki/Cis_(mathematics)
## Copyright (C) 1999,2021,2023 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
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## 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
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1995/11/13 03:49:00
## File existed as early as: 1995
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/