Check expr or How can I do math in Tcl, where hyperbolic cosine are invoked...

DKF: Tcl 8.5 includes support for hyperbolic cosines via the cosh() expr function and the tcl::mathfunc::cosh command.

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Also:

What: COSH

 Where: http://home.t-online.de/home/dshepherd/cosh.htm
 Description: Windows shell interface to Tcl and Tk, providing a COM interface.
        COSH can be remotely started on any machine via appropriate
        Win32 call (uses a COM Class factory).  Can be called from
        COM automation clients such as Visual Basic and Delphi.
 Updated: 03/1998
 Contact: mailto:dshepherd@t-online.de  (David Shepherd)

escargo 10 Mar 2006 - Link no longer points to anything useful.

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I think it a very poor idea to name a thing (the extension) with a name that has a specific and well known other meaning. I thought I was going off to look at an implementation of hyperbolic cosine in pure Tcl. -PSE

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