Re: FullSimplify doesn't simplify
- To: mathgroup at smc.vnet.net
- Subject: [mg32780] Re: FullSimplify doesn't simplify
- From: lalu_bhatt at yahoo.com (Bhuvanesh)
- Date: Sat, 9 Feb 2002 05:11:57 -0500 (EST)
- References: <a404nb$bqk$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Ken Morgan" <kmorga51 at calvin.edu> wrote:
> 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?
>
>
> Thanks,
> Ken Morgan
> kmorga51 at calvin.edu
It is apparently not true when both x and y are negative and n is not an integer:
In[1]:= (x y)^n - (x^n)(y^n) /. {x->-1, y->-2, n->1/2}
Out[1]= 2 Sqrt[2]
In[2]:= FullSimplify[(x y)^n - (x^n)(y^n), n \[Element] Integers]
Out[2]= 0
In[3]:= FullSimplify[(x y)^n - (x^n)(y^n), x>0]
Out[3]= 0
--
Bhuvanesh,
Wolfram Research.