Original Version

1 files changed, 26 insertions, 0 deletions

diff --git a/src/c/elementaryFunctions/cosh/dcoshs.c b/src/c/elementaryFunctions/cosh/dcoshs.c
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+++ b/src/c/elementaryFunctions/cosh/dcoshs.c
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+/*
+ *  Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+ *  Copyright (C) 2008-2008 - INRIA - Bruno JOFRET
+ *
+ *  This file must be used under the terms of the CeCILL.
+ *  This source file is licensed as described in the file COPYING, which
+ *  you should have received as part of this distribution.  The terms
+ *  are also available at
+ *  http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
+ *
+ */
+
+/*
+//         cosh(z) = 0.5 (exp(|z|) + exp(-|z|))
+//                 = 0.5 ( y + 1/y ) with y = exp(|z|)
+*/
+
+#include <math.h>
+#include "cosh.h"
+#include "exp.h"
+#include "abs.h"
+
+double	       dcoshs(double x) {
+  double y = dexps(dabss(x));
+  return (0.5 * (y + 1.0/y));
+}