Re: Simplify problems for checking easy equalities...

• To: mathgroup at smc.vnet.net
• Subject: [mg53859] Re: Simplify problems for checking easy equalities...
• From: "Scout" <user at domain.com>
• Date: Tue, 1 Feb 2005 04:08:10 -0500 (EST)
• References: <cti5nd\$8n2\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```You have to use assumptions:

In[1]:=
Simplify[ Log[x^n] - n*Log[x], {x\[Element]Reals, x>0,n\[Element]Reals}]

Out[1]:=
0

Log(x) is defined for real x in (0;Infinity)

~Scout~

"Cyrus Erik Eierud" <cyruserik at tele2.se> ha scritto nel messaggio
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
>

```

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