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Re: Simplify exponents in output

  • To: mathgroup at smc.vnet.net
  • Subject: [mg99236] Re: [mg99155] Simplify exponents in output
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 30 Apr 2009 06:25:12 -0400 (EDT)
  • Reply-to: hanlonr at cox.net

expr = (64 x^9)^(1/3)

4*(x^9)^(1/3)

Assuming[{x >= 0}, Simplify[expr]]

4*x^3

Simplify[expr, x >= 0]

4*x^3

{expr, 4 x^3} /. x -> 3

{108, 108}

{expr, 4 x^3} /. x -> -3

{108*(-1)^(1/3), -108}

% // N

{54.000000000000014 + 
     93.53074360871936*I, -108.}


Bob Hanlon

---- davef <davidfrick2003 at yahoo.com> wrote: 

=============
When I attempt to solve the following  in Mathematica:

(64 x^9)^(1/3)

I get this:

4 (x^9)^1/3

Why don't I get:

4x^3

IOW, why doesn't Mathematica simplify the variable under the radical in the output?

I am using Mathematica 7.

Thanks.



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