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• To: mathgroup at smc.vnet.net
• Subject: [mg77827] question
• From: dimitris <dimmechan at yahoo.com>
• Date: Sun, 17 Jun 2007 06:21:19 -0400 (EDT)

Two eforts in Mathematica 5.2 in order
to simplify o below

o = 2*Cos[Pi/48]*(1 - Cos[Pi/48]^2)^(1/2) + 2*Cos[Pi/48]^2 - 1;

First leaving Mathematica do the job.

Timing[ToRadicals[RootReduce[(FullSimplify[#1, ComplexityFunction ->
(Count[{#1}, _Cos, Infinity] & )] & )[o]]]]
{43.031*Second, Sqrt[(1/2)*(2 + Sqrt[2 - Sqrt[3]])]}

Then help a bit Mathematica.
I couldn't find a built in command to simplify 1 - Cos[Pi/48]^2 to
Sin[Pi/48]^2. That's why the adding of a rule.

Timing[ToRadicals[RootReduce[Simplify[o /. 1 - Cos[Pi/48]^2 ->
Sin[Pi/
48]^2]]]]
{0.25*Second, Sqrt[(1/2)*(2 + Sqrt[2 - Sqrt[3]])]}

Any other suggestions will be highly appreciated.

Dimitris

• Follow-Ups:
  • Re: question
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>
  • Re: question
    • From: Carl Woll <carlw@wolfram.com>