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Re: Mathematica bug??

  • To: mathgroup at smc.vnet.net
  • Subject: [mg100577] Re: Mathematica bug??
  • From: Peter Breitfeld <phbrf at t-online.de>
  • Date: Mon, 8 Jun 2009 02:08:42 -0400 (EDT)
  • References: <h0fvlb$rct$1@smc.vnet.net>

oshaughn wrote:

> {{Sqrt[1 - 2/r], 0, 0, 0}, {0, 1/Sqrt[1 - 2/r], 0, 0}, {0, 0, r,
>    0}, {0, 0, 0, r Sin[\[Theta]]}} // Inverse
>
> gives
>
> {{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 1/r, 0}, {0, 0, 0, Csc[\[Theta]]/
>   r}}
>
> with no warnings.  This is a *diagonal* matrix that should be
> trivially invertible.
>
> Does anyone know why Inverse has catastrophically failed here?
>

I get the result:

{{1/Sqrt[1 - 2/r], 0, 0, 0}, {0, Sqrt[1 - 2/r], 0, 0}, {0, 0, 1/r, 
  0}, {0, 0, 0, Csc[\[Theta]]/r}}

which seems to be correct. Maybe you have set Values to some of your
variables.   

-- 
_________________________________________________________________
Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de


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