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+## Copyright (C) 1998 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 2, 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, write to the Free
+## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+## 02111-1307, USA.
+
+## usage: beta (a, b, x)
+##
+## Compute the incomplete beta function
+##
+##  betai (a, b, x) = beta(a,b)^(-1) \int_0^x t^(a-1) (1-t)^(b-1) dt
+##
+## The sizes of x, a, and b must agree.
+
+## Author: jwe
+## Created: 30 Jan 1998
+
+function retval = betai (a, b, x)
+
+  if (nargin == 3)
+    retval = betainc (x, a, b);
+  else
+    usage ("betai (a, b, x)");
+  endif
+
+endfunction