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Re: Integrating hyperbolic functions

• To: mathgroup at yoda.ncsa.uiuc.edu
• Subject: Re: Integrating hyperbolic functions
• From: mcdonald at quark.umd.edu (Bill MacDonald)
• Date: Wed, 21 Nov 90 18:25:44 EST

> 
> Is there a way to prevent Mathematica to turn a hyperbolic function (e.g.
> Cosh) into exponentials?  I want to have:
> 
> 	Integrate[Cosh[x],x]   ==> Sinh[x]
> 
> I tried to define an integration rule using Literal on the lhs, but then
> when I input "Integrate[Cosh[x],x]", the Cosh is turned into exponentials
> and therefore does not match the rule.  Is there a Quote in mathematica?
> (Hold doesn't quite do the job either.) 
> 
> Any suggestion will be appreciated.
> 
> 
> 
> 
> 
> 
The only solution I have found to Mathematica's persistence in
decomposing hyperbolic functions is to define rules for convverting the
sum and difference of exponentials t my own sinh and cosh.  It is useful
to define the appropriate rules for reducing expressions involving
hyperbolic functions, just as TrigReduce do for trigonometric functions.



-- 

William M. MacDonald
Professor of Physics
University of Maryland
Internet: mcdonald at quark.umd.edu
Bitnet:mAcdonald at cincom