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Re: Exact real parts

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31206] Re: Exact real parts
  • From: "Allan Hayes" <hay at haystack.demon.co.uk>
  • Date: Fri, 19 Oct 2001 03:11:55 -0400 (EDT)
  • References: <9qjjv7$j8i$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Mark:
h = Table[1/(i + j - 1), {i, 3}, {j, 3}];
ev=Eigenvalues[h];

ComplexExpand[Re[ev]]

{(1/90)*(46 + Sqrt[6559]*
     Cos[(1/3)*ArcTan[(405*Sqrt[89799])/517148]]),
  (1/180)*(92 - Sqrt[6559]*
     (Cos[(1/3)*ArcTan[(405*Sqrt[89799])/517148]] +
      Sqrt[3]*Sin[(1/3)*ArcTan[(405*Sqrt[89799])/517148]])),
  (1/180)*(92 + Sqrt[6559]*
     (-Cos[(1/3)*ArcTan[(405*Sqrt[89799])/517148]] +
      Sqrt[3]*Sin[(1/3)*ArcTan[(405*Sqrt[89799])/517148]]))}

--
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565

"DIAMOND Mark R." <dot at dot.dot> wrote in message
news:9qjjv7$j8i$1 at smc.vnet.net...
> Is it possible to get Mathematica to provide the exact real parts of
> something like the 3x3 Hilbert matrix?
>
> h = Table[1/(i + j - 1), {i, 3}, {j, 3}];
> Eigenvalues[h]
>
> N and Chop will obviously give their approximations.
>
> Cheers
> --
> Mark R. Diamond
> Send email to  psy dot uwa dot edu dot au and address to markd
> http://www.psy.uwa.edu.au/user/markd
>
>
>




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