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Re: Simplify problems for checking easy equalities...

• To: mathgroup at smc.vnet.net
• Subject: [mg53864] Re: Simplify problems for checking easy equalities...
• From: "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk>
• Date: Tue, 1 Feb 2005 04:08:14 -0500 (EST)
• References: <cti5nd$8n2$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Your expression does not simplify to zero in general.

However, the following does what I suspect you require:

Simplify[Log[x^n] - n*Log[x], x>0 && n \[Element] Integers]

Steve Luttrell

"Cyrus Erik Eierud" <cyruserik at tele2.se> wrote in message 
news:cti5nd$8n2$1 at smc.vnet.net...
> Please Help!
>
> Thanks for all great answers I've already found here!
> My problem is that I can not simplify what to me seems as a very
> simple equality task. This is what I want Mathematica to return zero
> for:
>
> in[1]:= FullSimplify[Log[x^n] - n*Log[x]]
>
> out[1]= -n Log[x] + Log[x^n])
>
> I have used Simplify to check equalities, but the one above (and many
> other equations similar to the one above) just don't simplify. Am I
> doing anything wrong or does anyone know of a better way to check
> equalities?
>
> Appreciate any help,
> Cyrus Eierud, Student
> cyruserik at tele2.se
>