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Re: Simplifying expressions containing Bessel functions?

• To: mathgroup at smc.vnet.net
• Subject: [mg76858] Re: Simplifying expressions containing Bessel functions?
• From: roland franzius <roland.franzius at uos.de>
• Date: Mon, 28 May 2007 05:11:24 -0400 (EDT)
• Organization: Universitaet Hannover
• References: <f3dpbp$ft0$1@smc.vnet.net>

AES wrote:
> Is there any kind of Simplification procedure in Mathematica that will 
> somehow apply the recursion relations between Bessel functions of orders 
> n-1, n and n+1 to eliminate the highest orders in an expression?
> 
> I realize this is not a simple topic -- but it would be nice if
> 
>    D[x BesselJ[1, x], x]
> 
> would yield
> 
>    x BesselJ[0, x]
> 
> rather than
> 
>    BesselJ[1, x]  +  (x/2) ( BesselJ[0, x] - BesselJ[2, x] )
> 

FunctionExpand obviously knows about the Bessel recursion.

-- 

Roland Franzius