       Re: Re: Simplifying algebraic expressions

• To: mathgroup at smc.vnet.net
• Subject: [mg66903] Re: [mg66877] Re: Simplifying algebraic expressions
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Sat, 3 Jun 2006 03:25:35 -0400 (EDT)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <200606020809.EAA18060@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```I think the original poster's intention was to ask how to make
Mathematica make the following simplifications:

(-1)^(2 x + 3 y)
((-1)^(2x)) * ((-1)^(3y))
(((-1)^2)^x) * ((-1)^(3y))
(1^x) * (-1)^(3y)
1 * (-1)^(3y)
(-1)^(3y)

Of course this is valid only in special circumstances, even when x and y
are real and positive.

Bill Rowe wrote:
> On 6/1/06 at 6:54 AM, aroy at cs.bc.edu (Amitabha Roy) wrote:
>
>> I would like Mathematica to be able to take an expression, say,
>
>> (-1)^{2 x  + 3 y} and be able to simplify to (-1)^y.
>
>> Is there a way one can do this ?
>
> I wonder if you really meant
>
> (-1)^{2 x + 3 y}
>
>
> (-1)^(2 x + 3 y)
>
> in any case, the only way to simplify the 2 x + 3 y part to y would be to define x as -y. That is
>
> (-1)^(2 x + 3 y)/.x->-y
>
> will return (-1)^y
>
> Or perhaps you wanted Mathematica to return (-1)^z where z is defined to be 2 x + 3 y? If so
>
> (-1)^(2 x + 3 y) /. (-1)^(n_) :> (-1)^z
>
> will return (-1)^z
> --
> To reply via email subtract one hundred and four
>
>

--
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

```

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