MathGroup Archive 2003

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: FullSimplify behavior

  • To: mathgroup at smc.vnet.net
  • Subject: [mg41726] Re: [mg41710] FullSimplify behavior
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Tue, 3 Jun 2003 07:13:08 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

On Monday, June 2, 2003, at 05:35  pm, Carlos Felippa wrote:

> I would like to get an understanding for the
> behavior of FullSimplify in the last two commands.
>
> Print[FullSimplify[Sin[Pi/4]]//InputForm];
> Print[FullSimplify[Sin[Pi/3]]//InputForm];
> Print[FullSimplify[Sin[Pi/8]]//InputForm];
> Print[FullSimplify[TrigToExp[Sin[Pi/8]]]//InputForm];
>
> 1/Sqrt[2]
> Sqrt[3]/2
> Sin[Pi/8]
> Sqrt[2 - Sqrt[2]]/2
>
> It is because FullSimplify views Sin[Pi/8] as "simpler" than
> Sqrt[2 - Sqrt[2]]/2 in terms of leaf count?  It seems that way
> since the counts given are 6 and 17, respectively. And the
> count of TrigToExp[Sin[Pi/8]] is 31.
>
> Counterargument(?). For the first two commands the leaf counts
> before and after FullSimplify are the same: 5 -> 5, and
> 10 -> 10, respectively, yet the transformation was done.
>
>
>

Actually since

Sin[Pi/4]


1/Sqrt[2]


Sin[Pi/3]


Sqrt[3]/2

FullSimplify never gets a chance to show what it can do.






Andrzej Kozlowski
Yokohama, Japan
http://www.mimuw.edu.pl/~akoz/
http://platon.c.u-tokyo.ac.jp/andrzej/


  • Prev by Date: Big problem in solving radicals.
  • Next by Date: Re: yield to maturity
  • Previous by thread: FullSimplify behavior
  • Next by thread: Re: Decimal point in printed numbers