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calc/help/tan
Landon Curt Noll 2c4abcd2b7 add cas and cis trigonometric functions
Added the following new trigonometric functions:

    cas(x [,eps])		trigonometric cosine plus sine
    cis(x [,eps])		Euler's formula
2023-10-03 01:41:42 -07:00

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NAME
tan - trigonometric tangent
SYNOPSIS
tan(x [,eps])
TYPES
x number (real or complex)
eps 0 < real < 1, defaults to epsilon()
return real
DESCRIPTION
Calculate the trigonometric tangent of x to a multiple of eps, with error less
in absolute value than .75 * eps.
This function is equivalent to:
tan(x) = sin(x) / cos(x)
EXAMPLE
; print tan(1/2), tan(5/7), tan(42/7)
0.54630248984379051326 0.8670082185107029875 -0.29100619138474915705
; print tan(1, 1e-5), tan(1, 1e-10), tan(1, 1e-15), tan(1, 1e-20)
1.55741 1.5574077247 1.557407724654902 1.55740772465490223051
; print tan(2 + 3i, 1e-5), tan(2 + 3i, 1e-10)
~-0.00376408798745471014+~1.00323845857938817252i ~-0.00376402563894634508+~1.00323862734859967572i
; pi = pi(1e-20)
; print tan(pi/6), tan(pi/2), tan(pi)
0.57735026918962576451 756606132568153667453.84481533280934425956 0
; # NOTE: The huge value for tan(pi/2) is because the pi variable is not exactly pi.
LIMITS
0 < eps < 1
LINK LIBRARY
NUMBER *qtan(NUMBER *x, NUMBER *eps)
COMPLEX *c_tan(COMPLEX *c, NUMBER *eps)
SEE ALSO
sin, cos, cot, sec, csc
asin, acos, atan, acot, asec, 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) 1999,2023 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: 1994/03/19 01:40:29
## File existed as early as: 1994
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/