Files
calc/help/cot
Landon Curt Noll bf730f5518 add cmappr() and missing complex tan, cot, sec, csc in liblcac
Added complex multiple approximation function to commath.c so
that users of libcalc may directly round complex number to
nearest multiple of a given real number:

    E_FUNC COMPLEX *cmappr(COMPLEX *c, NUMBER *e, long rnd, bool cfree);

For example:

    COMPLEX *c;             /* complex number to round to nearest epsilon */
    NUMBER *eps;            /* epsilon rounding precision */
    COMPLEX *res;           /* c rounded to nearest epsilon */
    long rnd = 24L;         /* a common rounding mode */
    bool ok_to_free;        /* true ==> free c, false ==> do not free c */

    ...

    res = cmappr(c, eps, ok_to_free);

The complex trigonometric functions tan, cot, sec, csc were implemented
in func.c as calls to complex sin and complex cos.  We added the
direct calls to comfunc.c so that users of libcalc may
call them directly:

    E_FUNC COMPLEX *c_tan(COMPLEX *c, NUMBER *eps);
    E_FUNC COMPLEX *c_cot(COMPLEX *c, NUMBER *eps);
    E_FUNC COMPLEX *c_sec(COMPLEX *c, NUMBER *eps);
    E_FUNC COMPLEX *c_cot(COMPLEX *c, NUMBER *eps);
2023-09-10 22:54:50 -07:00

70 lines
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NAME
cot - trigonometric cotangent
SYNOPSIS
cot(x [,eps])
TYPES
x number (real or complex)
eps 0 < real < 1, defaults to epsilon()
return real
DESCRIPTION
Calculate the cotangent of x to a multiple of eps, with error less
in absolute value than .75 * eps.
This function is equivalent to:
cot(x) = cos(x) / sin(x)
EXAMPLE
; print cot(1, 1e-5), cot(1, 1e-10), cot(1, 1e-15), cot(1, 1e-20)
0.64209 0.6420926159 0.642092615934331 0.64209261593433070301
; print cot(2 + 3i, 1e-5), cot(2 + 3i, 1e-10)
~-0.00373977357605613583-~0.99675796378381737782i ~-0.00373971037383300017-~0.99675779657435500069i
; pi = pi(1e-20)
; print cot(pi/12, 1e-10), cot(pi/6, 1e-10), cot(pi/3, 1e-10), cot(pi/2, 1e-10)
3.7320508076 1.7320508076 0.5773502692 0
; print cot(1/2), cot(5/7), cot(42/7)
1.83048772171245191927 1.15339160419695060142 -3.43635300418012783207
LIMITS
0 < eps < 1
LINK LIBRARY
NUMBER *qcot(NUMBER *x, NUMBER *eps)
COMPLEX *c_cot(COMPLEX *c, NUMBER *eps)
SEE ALSO
sin, cos, tan, sec, csc
asin, acos, atan, acot, asec, acsc
versin, coversin, vercos, avercos
aversin, acoversin, covercos, acovercos
epsilon
## 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/