Re: how to get Mathematica to reduce simple expressions?
- To: mathgroup at smc.vnet.net
- Subject: [mg45206] Re: how to get Mathematica to reduce simple expressions?
- From: drbob at bigfoot.com (Bobby R. Treat)
- Date: Sat, 20 Dec 2003 05:56:22 -0500 (EST)
- References: <brs58p$ika$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
(a^(3/2)*(m^2/(m^2 + t^2*a^2*h^2))^(3/2))/
((m^2*a)/(m^2 + t^2*a^2*h^2))^(3/2);
FullSimplify[%, {a > 0}]
1
or
PowerExpand[(a^(3/2)*(m^2/(m^2 + t^2*a^2*h^2))^(3/2))/
((m^2*a)/(m^2 + t^2*a^2*h^2))^(3/2)]
1
If a < 0 or complex, the value may depend on a choice of branch for
#^(3/2)&. If a==0, it isn't defined. So... I'd say Mathematica is
doing it right.
Bobby
Peter Jay Salzman <p at dirac.org> wrote in message news:<brs58p$ika$1 at smc.vnet.net>...
> Hi all,
>
> I've been using Mathematica to check some of my calculations, and one of the
> integrals,
>
> 4 Pi Integrate[r^2 Bra[r,t] Ket[r,t], {r, 0, Infinity},
> Assumptions -> {Re[m^2*a/(m^2 + t^2*a^2*h^2)] > 0}]
> // FullSimplify
>
>
>
> yielded the result:
>
>
>
> Out[176]=
> 2
> 3/2 m 3/2
> a (-------------)
> 2 2 2 2
> m + t a h
> -----------------------
> 2
> m a 3/2
> (-------------)
> 2 2 2 2
> m + t a h
>
>
> which is 1. i'm more curious than anything else: how do i coax Mathematica to
> reduce this seemingly simple expression?
>
> why is Mathematica doing this?
>
> thanks!
> pete