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Re: kernel problem for trigonometry

• To: mathgroup at smc.vnet.net
• Subject: [mg29850] Re: kernel problem for trigonometry
• From: "Orestis Vantzos" <atelesforos at hotmail.com>
• Date: Fri, 13 Jul 2001 04:19:30 -0400 (EDT)
• Organization: National Technical University of Athens, Greece
• References: <9ijhqn$rhr$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Well, the trig expression does not evaluate to anything by itself, unless
you use N to turn it into a real number.
By calling FullSimplify you tell Mathematica to apply trig identities in an
effort to simplify the expr. It is obvious that simple arguments like Pi, 2
Pi, Pi/2, Pi/3 etc. simplify immedaitely to algebraic expressions involving
simple roots. Not so classical arguments like 220deg do not map readily to
algebraic expr. of roots. It is obvious that there is a wide range of
possible transformation that could be applied, so it is only natural that
FullSimplify takes a lot of time to navigate through the mess of trig
identiies.
Orestis
"Soh Pek Hooi" <fbasohph at nus.edu.sg> wrote in message
news:9ijhqn$rhr$1 at smc.vnet.net...
> Hi,
>
> May I find out the reason for the Kernel to compute the following with
> longer than the normal response time? It take several minutes to return a
> value, especially when the degree is not one of 0, 30, 45, 90 Degrees, and
> so on.
>
> FullSimplify[Sin[110 Degree]/Cos[220Degree]]
>
> Will appreciate your reply.
>
> Pek
>