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Re: Silly question on Matrices

  • To: mathgroup at smc.vnet.net
  • Subject: [mg111560] Re: Silly question on Matrices
  • From: Simon <simonjtyler at gmail.com>
  • Date: Thu, 5 Aug 2010 07:00:13 -0400 (EDT)
  • References: <i3bd6b$pi8$1@smc.vnet.net>

This is such a common Mathematica gotcha that it should be documented
properly.

The MatrixForm documentation says:
         MatrixForm acts as a "wrapper", which affects printing, but
not evaluation.
Which is true provided you know your Mathematica operator ordering.
Maybe the docs need a Possible Issues section??


On Aug 4, 7:51 pm, "Eduardo M. A. M.Mendes" <emammen... at gmail.com>
wrote:
> Hello there
>
> I am new to Mathematica.  In one of my attempts to understand how it works,
> I tried the following example
>
> A={{1,2,3},{4,5,6},{7,8,9}} //MatrixForm
>
> The result seems to be a matrix 3x3 but when I try A[[1][1]], the whole
> first line shows up instead of just one element.  If I don't use MatrixForm,
> it works fine.  How can I see a matrix in nice format without wrecking
> everything?
>
> Many thanks
>
> Ed



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