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

Re: Collecting like terms after TrigReduce

• To: mathgroup at smc.vnet.net
• Subject: [mg108938] Re: Collecting like terms after TrigReduce
• From: dh <dh at metrohm.com>
• Date: Wed, 7 Apr 2010 07:26:36 -0400 (EDT)
• References: <hphbm2$lhn$1@smc.vnet.net>

On 07.04.2010 09:19, Geico Caveman wrote:
> I have a large expression that is expressed (after TrigReduce) as a
> series of the form:
>
> c1*cos(wt) + s1*sin(2wt) + a1+c2*cos(2 wt) + c3* cos(wt) + s2*sin(wt) +
> c4*cos(wt) + a2+c4*cos(2wt) + s3 sin(2wt)
>
> (This is just an illustrative example. The precise number of terms is
> larger and the number of each kind, impossible to know ahead of the
> calculation.)
>
> Is there any way (for compactness reasons alone) to force Mathematica
> to put this in a standard form:
>
> (a1+a2) + (c1+c3) cos(wt) + (c2 + c4)cos (2wt) + s2 sin(wt) + (s1+s3)
> sin(2wt) ?
>
> Using Simplify is not an option since that gets rid of the higher
> harmonic terms (which I want).
>
Hi Geico,
what do you mean by: "Simplify is not an option since that gets rid of 
the higher harmonic terms"? Simplify does NOT eliminate terms. Simplify 
applied to the given expression yields:
a1 + a2 + (c1 + c3 + c4) Cos[wt] + (c2 + c4) Cos[2 wt] + s1 Sin[wt] +
  s2 Sin[wt] + s3 Sin[2 wt]
Daniel

-- 

Daniel Huber
Metrohm Ltd.
Oberdorfstr. 68
CH-9100 Herisau
Tel. +41 71 353 8585, Fax +41 71 353 8907
E-Mail:<mailto:dh at metrohm.com>
Internet:<http://www.metrohm.com>