Re: can't MATHEMATICA simplify simple expressions?

• To: mathgroup at smc.vnet.net
• Subject: [mg51540] Re: can't MATHEMATICA simplify simple expressions?
• Date: Thu, 21 Oct 2004 22:21:09 -0400 (EDT)
• References: <cl4tg0\$8g7\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```The problem is that you are assuming that "a" is a real number.  While
this is normal for most humans, it need not be in a strict
mathematical sense.  By default Mathematica assumes all variables can
be complex.  For a complex number the result is not simply a^3.

You can place conditions on the simplicication:
For example if a>0

In[4]:=
FullSimplify [ (a^2)^(3/2),a>0 ]

Out[4]=
a^3

For a simply a real number

In[5]:=
FullSimplify [ (a^2)^(3/2),Element[a,Reals] ]

Out[5]=
Abs[a]^3

Cole Turner <REMOVEcole.tuner at liwest.at> wrote in message news:<cl4tg0\$8g7\$1 at smc.vnet.net>...
> if I enter:
>
> FullSimplify [ (a^2)^(3/2) ]
>
> (in correct MATHEMATICA syntax, the program does not yield the correct
> result, a^3 ...
>
> why is that?
>
> thanks!

```

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