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Re: kernel problem for trigonometry

• To: mathgroup at smc.vnet.net
• Subject: [mg29862] Re: [mg29820] kernel problem for trigonometry
• From: "Fred Simons" <f.h.simons at tue.nl>
• Date: Sat, 14 Jul 2001 01:36:52 -0400 (EDT)
• References: <200107120652.CAA28174@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

----- Original Message -----
From: Soh Pek Hooi <fbasohph at nus.edu.sg>
To: mathgroup at smc.vnet.net
Subject: [mg29862] [mg29820] kernel problem for trigonometry


> 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

FullSimplify is just a box of simplification tricks that might work in some
cases. Examples exist (and will exist for any implementation of
FullSimplify) that are equal to zero but cannot be reduced to zero by
FullSimplify.

When you know yourself how to simplify an expression, it is always
better to do it in your way. For your expression I would use FunctionExpand,
which on my computer takes 0. Second. But maybe you are looking for a
"simpler" result?

Regards,

Fred Simons
Eindhoven University of Technology

• References:
  • kernel problem for trigonometry
    • From: Soh Pek Hooi <fbasohph@nus.edu.sg>