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Re: Incompletely simplified Square root.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg121065] Re: Incompletely simplified Square root.
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Fri, 26 Aug 2011 05:22:16 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201108251104.HAA24880@smc.vnet.net>


On 25 Aug 2011, at 13:04, paulvonhippel at yahoo wrote:

> Can someone tell me why the following input doesn't produce an output
> of 0.68....?
> Why is the output under the radical? Thanks!
>
> In[574]:= Sqrt[\!\(\*
> TagBox[
> FractionBox["926", "2025"],
> PolynomialForm]\)] // N
>
> Out[574]= Sqrt[\!\(\*
> TagBox["0.45728395061728394`",
> PolynomialForm]\)]
>

Because PolynomialForm[926/2025] is not a number so you can't extract a square root of it or even perform any arithmetical operations on it. For example, try
 1 + PolynomialForm[926/2025].

The same will be true with any other "Forms", e.g.

1 + InputForm[1]

InputForm[1] + 1

You have obviously misunderstood what these wrappers are. Also, why are you using PolynomialForm in this way, anyway, it's obviously not doing anything useful?

Andrzej Kozlowski







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