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MathGroup Archive 1997

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trig expansion

  • To: mathgroup at smc.vnet.net
  • Subject: [mg8854] trig expansion
  • From: murray at math.umass.edu (Murray Eisenberg)
  • Date: Tue, 30 Sep 1997 20:16:15 -0400
  • Organization: University of Massachusetts, Amherst
  • Sender: owner-wri-mathgroup at wolfram.com

How can I cause Mathematica to expand Sin[2 Pi omega t + 2 Pi delta],
where delta and omega are symbols, into the form

   Cos[2 Pi delta] Sin[2 Pi omega t] + Sin[2 Pi delta] Cos[2 Pi omega t]

without using a replacment rule 

    Sin[a_ + b_] -> Sin[a]Cos[b] + Cos[a]Sin[b]

explicitly?  (No TrigExpand does NOT do the trick -- it expands all
the way down to trig functions of Pi delta and Pi t omega!)

--
  Murray Eisenberg                       Internet:  murray at math.umass.edu
  Mathematics & Statistics Dept.            Voice:  413-545-2859 (W)
  University of Massachusetts                       413-549-1020 (H)
  Amherst, MA 01003                           Fax:  413-545-1801


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