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Re: Expand[] on the RHS of a rule

• To: mathgroup at yoda.physics.unc.edu
• Subject: Re: Expand[] on the RHS of a rule
• From: Silvio Levy <levy at geom.umn.edu>
• Date: Thu, 28 May 92 09:34:26 CDT

> From: athos at warp.stanford.edu (Athos Kasapi) (see below)

> Has anybody found a way to work around the problem that Expand does not
> work when it is on the right hand side of a rule?  For example, if I
> define
> 
> p := Sqrt[ (a + b) (c + d) ]
> 
> and then apply the rule
> 
> p /. Sqrt[ x_ y_ ] -> Sqrt[ Expand[ x y ] ]
> 
> Then all I get back is
> 
> Sqrt[ (a + b)(c + d) ]

The problem is not with Expand; you have the wrong kind of rule.
Try :> instead of ->

Silvio