Re: Re: (a/b)^2 when a/b is replaced by e won't yield e^2

*To*: mathgroup at smc.vnet.net*Subject*: [mg61423] Re: [mg61397] Re: (a/b)^2 when a/b is replaced by e won't yield e^2*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 19 Oct 2005 02:16:03 -0400 (EDT)*References*: <dinvoj$s6i$1@smc.vnet.net><200510150223.WAA17341@smc.vnet.net> <diskhc$m7i$1@smc.vnet.net> <200510180644.CAA11192@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On 18 Oct 2005, at 15:44, mike_in_england2000 at yahoo.co.uk wrote: >> HoldForm[(a/b)^2] /. (a/b) -> e >> > > >> HTH >> > > >> Mike >> > > >>> If you want to do it this way it is better to use Unevaluated rather >>> than HoldForm: >>> > > >>> Unevaluated[(a/b)^2] /. (a/b) -> e >>> > > >> Andrzej Kozlowski >> Tokyo, Japan >> > > Hi Andrzej > > Thanks for the reply - I didn't know about the Unevaluated command - > why is it better to use it rather than HoldForm? I am not disputing > what you say - I just would like to understand. > > Thanks > > Mike > > Because it is immediately stripped off, so you do not need to use ReleaseHold to actually use it as input. Look at the outputs in InputForm: In[9]:= HoldForm[(a/b)^2] /. a/b -> e Out[9]= HoldForm[e^2] In[10]:= Unevaluated[(a/b)^2] /. a/b -> e Out[10]= e^2 Andrzej Kozlowski Tokyo, Japan

**References**:**Re: (a/b)^2 when a/b is replaced by e won't yield e^2***From:*mike_in_england2000@yahoo.co.uk

**Re: (a/b)^2 when a/b is replaced by e won't yield e^2***From:*mike_in_england2000@yahoo.co.uk