       Re: Simplify problems for checking easy equalities...

• To: mathgroup at smc.vnet.net
• Subject: [mg53874] Re: Simplify problems for checking easy equalities...
• From: "Dr. Wolfgang Hintze" <weh at snafu.de>
• Date: Tue, 1 Feb 2005 04:08:25 -0500 (EST)
• References: <cti5nd\$8n2\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Try to impose reasonable conditions on x and n:

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

Out=
True

or

In:=
Simplify[Log[x^n] == n*Log[x], {x > 0, Im[n] == 0}]

Out=
True

but it's not enough to just say x>0:

In:=
Simplify[Log[x^n] == n*Log[x], x > 0]

Out=
Log[x^n] == n*Log[x]

Hopre this hepls
Wolfgang

Cyrus Erik Eierud wrote:

>
> 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:= FullSimplify[Log[x^n] - n*Log[x]]
>
> out= -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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