Re: Simplify problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg95841] Re: Simplify problem*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Wed, 28 Jan 2009 06:33:21 -0500 (EST)

On 1/27/09 at 6:58 AM, tidy512 at googlemail.com wrote: >I am using Simplify / FullSimplify etc. to simplify some equations I >have, but I am unable to coerce Mathematica into automatically >giving me the form I require for some of the sub-expressions, e.g. >I'd like >1/Sqrt[1 + 1/x] >to be automatically converted to >Sqrt[x/(1 + x)] You can make the desired conversion by using Together. That is In[21]:= 1/Sqrt[1 + 1/x] // Together Out[21]= 1/Sqrt[(x+1)/x] But since In[22]:= LeafCount[%] Out[22]= 11 and In[23]:= 1/Sqrt[1 + 1/x] // LeafCount Out[23]= 9 Simplify or FullSimplify will clearly not do what you want since 1/Sqrt[1 + 1/x] has a lower LeafCount and therefore simpler by the definitions of simpler used in these functions. The real issue is there is no universal definition of simpler for arbitrary expressions. You could modify Simplify/FullSimplify to do what you want in this case. But doing so is likely to have undesirable effects in some other cases.