## Copyright (C) 1994-2017 John W. Eaton
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave 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
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {} {} coth (@var{x})
## Compute the hyperbolic cotangent of each element of @var{x}.
## @seealso{acoth}
## @end deftypefn

## Author: jwe

function y = coth (x)

  if (nargin != 1)
    print_usage ();
  endif

  y = 1 ./ tanh (x);

endfunction


%!test
%! x = [pi/2*i, 3*pi/2*i];
%! v = [0, 0];
%! assert (coth (x), v, sqrt (eps));

%!error coth ()
%!error coth (1, 2)
