Re: FullSimplify doesn't simplify
- To: mathgroup at smc.vnet.net
- Subject: [mg32775] Re: FullSimplify doesn't simplify
- From: Steve Luttrell <luttrell at signal.qinetiq.com>
- Date: Sat, 9 Feb 2002 05:11:48 -0500 (EST)
- Organization: QinetiQ
- References: <a404nb$bqk$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Try this one, which gives the result {Sqrt[6], -Sqrt[6]}:
{(x y)^n, x^n y^n} /. {x -> -2, y -> -3, n -> 1/2}
The two expressions evaluate to different results because fractional
powers have multiple values.
On the other hand the following gives the result True, because you
explicitly state that n is an integer (i.e. not a fractional) power:
Simplify[(x y)^n == x^n y^n, n \[Element] Integers]
Steve Luttrell
"Ken Morgan" <kmorga51 at calvin.edu> wrote in
news:a404nb$bqk$1 at smc.vnet.net:
> Does anyone know why Mathematica doesn't simplify the following to
> True?
>
>
> In[1] := FullSimplify[(x y)^n == (x^n)(y^n)]
>
> Out[1] := (x y)^n == (x^n)(y^n)
>
> Are there cases where this is not true?