Re: Why can't Mathematica simplify this?
- To: mathgroup at smc.vnet.net
- Subject: [mg85014] Re: [mg85010] Why can't Mathematica simplify this?
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Thu, 24 Jan 2008 04:39:59 -0500 (EST)
- References: <200801221040.FAA08559@smc.vnet.net>
On 22 Jan 2008, at 10:40, dudesinmexico at gmail.com wrote:
>
> I think that Mathematica should be able to simplify this, since N and
> and l
> are constrained to be Integers:
>
> Simplify[Sin[2 Pi l (N - 1) /N], {N, l} \[Element] Integers]
>
> Instead, I get the same expression
>
> Sin[(2 l (-1 + N) Pi)/N]
>
> Does anyone know why?
>
> Thanks
>
>
Presumably the simpler expression you expected is:
FullSimplify[TrigToExp[Sin[(2*Pi*l*(N - 1))/N]],
Element[N | l, Integers]]
-Sin[(2*l*Pi)/N]
FullSimplify often performs better on expressions in exponential
rather than trigonometric form.
Andrzej Kozlowski
- References:
- Why can't Mathematica simplify this?
- From: dudesinmexico@gmail.com
- Why can't Mathematica simplify this?