Multiples of %pi



I think it would be better if we just improved %piargs-sin/cos (trigi.lisp).

        -s

On Sat, Jan 23, 2010 at 2:11 PM, Barton Willis <willisb at unk.edu> wrote:

> Two workarounds:
>
>  (%i1) e : sin(234*%pi/11);
>  (%o1) sin((234*%pi)/11)
>
>  (%i2) rectform(exponentialize(e));
>  (%o2) -sin((8*%pi)/11)
>
>  (%i3) load(spangl)$
>
>  (%i4) sin(234*%pi/11);
>  (%o4) -cos((5*%pi)/22)
>
> Is spangl reliable? I don't think there are regression tests for spangl.
>
> Barton
>
> -----maxima-bounces at math.utexas.edu wrote: -----
>
> >To: maxima mailing list <maxima at math.utexas.edu>
> >From: Stavros Macrakis <macrakis at alum.mit.edu>
> >Sent by: maxima-bounces at math.utexas.edu
> >Date: 01/22/2010 02:45PM
> >Subject: Multiples of %pi
> >
> >Jose brings up a good point below.
> >
> >Why aren't we simplifying e.g. sin(234*%pi/11) => -sin(3*%pi/11) ?
> >
> >            -s
> >
> >---------- Forwarded message ----------
> >From: Jose <jose.bray at free.fr>
> >
> >Date: 2010/1/17
> >Subject: [Maxima-lang-fr] simplification trigonometrique
> >To: maxima-lang-fr at lists.sourceforge.net
> >
> >
> >Bonjour, la commande :
> >
> >
> >
> >bfloat(cos(400.0*%pi/9.0)-cos(4.0*%pi/9.0))
> >
> >
> >
> >(notez que 400 pi / 9 est ?gal ? 4 pi / 9 modulo 2 pi)
> >
> >
> >
> >ne me renvoie pas 0 ; pas plus qu'une ?valuation symbolique de cos (400
> >
> >pi / 9) - cos (4 pi /9 ) , ou du moins dans ce cas, je n'ai pas trouv?
> >
> >la commande le permettant...
> >
> >
> >
> >Y a-t-il une explication ? ?a ?
> >
> >
> >
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