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Re: can't MATHEMATICA simplify simple expressions?

• To: mathgroup at smc.vnet.net
• Subject: [mg51555] Re: can't MATHEMATICA simplify simple expressions?
• From: "Dana DeLouis" <delouis at bellsouth.net>
• Date: Thu, 21 Oct 2004 22:22:26 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

I believe with square roots, there are usually two answers.  For example,
here we see that the answer could be + - 2.

 

In[1]:=(a^2)^(3/2) /. a -> 2

Out[1]=8

 

 

In[2]:=(a^2)^(3/2) /. a -> -2

Out[2]=8

 

Two ideas.

 

In[3]:=

Assuming[a > 0, FullSimplify[(a^2)^(3/2)]]

 

Out[3]=a^3

 

In[4]:=

FullSimplify[(a^2)^(3/2), Assumptions -> a > 0]

 

Out[4]=a^3

 

HTH

-- 

Dana DeLouis

Win XP & Office 2003

 

 

"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!

> -- 

> Johnny: [plugging back in the runway lights] 

>          "Just kidding."

>                   ('Airplane!', 1980)

>