--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/elfun/tand.m	Wed Jan 10 22:53:59 2007 +0000
@@ -0,0 +1,40 @@
+## Copyright (C) 2006 David Bateman <dbateman@free.fr>
+##
+## This program 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 2 of the License, or
+## (at your option) any later version.
+##
+## This program 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 this program; if not, write to the Free Software
+## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} tand (@var{x})
+## Compute the tangent of an angle in degrees.  Returns zero for elements
+## of for which @code{@var{x}/180} is an integer and @code{Inf} for elements
+## where @code{(@var{x}-90}/180} is an integer.
+## @seealso{tan, cosd, sind, acosd, asind, atand}
+## @end deftypefn
+
+function y = tand (x)
+  if (nargin != 1)
+    print_usage ();
+  endif
+  I0 = x / 180;
+  I90 = (x-90) / 180;
+  y = tan (I0 .* pi);
+  y(I0 == round (I0) & finite (I0)) = 0;
+  y(I90 == round (I90) & finite (I90)) = Inf;
+endfunction;
+
+%!error(tand())
+%!error(tand(1,2))
+%!assert(tand(10:10:80),tan(pi*[10:10:80]/180),-10*eps)
+%!assert(tand([0,180,360]) == 0)
+%!assert(tand([90,270]) == Inf)