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MathGroup Archive 1996

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ts ts ts

  • To: mathgroup at smc.vnet.net
  • Subject: [mg4979] ts ts ts
  • From: afritzse at limmat.ch (Arthur Fritzsche)
  • Date: Thu, 17 Oct 1996 00:40:56 -0400
  • Organization: Zurich Wiedikon-Friesenberg, Switzerland
  • Sender: owner-wri-mathgroup at wolfram.com

Hi there.

Does anybody know why Mathematica gets choked trying to solve
this simple equation? (seems like an easy way to calculate Fourier series up to n=3)

---------------------------------
x1=3
y1=3
x2=4
y2=4
x3=5
y3=5
x4=10
y4=-20
x5=11
y5=30
x6=12
y6=-30
x7=18
y7=0

Solve[{
    y1==a0+a1 Cos[x1]+b1 Sin[x1]+a2 Cos[2 x1]+b2 Sin[2 x1]+a3 Cos[3 x1]+
        b3 Sin[3 x1], 
    y2==a0+a1 Cos[x2]+b1 Sin[x2]+a2 Cos[2 x2]+b2 Sin[2 x2]+a3 Cos[3 x2]+
        b3 Sin[3 x2],
    y3==a0+a1 Cos[x3]+b1 Sin[x3]+a2 Cos[2 x3]+b2 Sin[2 x3]+a3 Cos[3 x3]+
        b3 Sin[3 x3],
    y4==a0+a1 Cos[x4]+b1 Sin[x4]+a2 Cos[2 x4]+b2 Sin[2 x4]+a3 Cos[3 x4]+
        b3 Sin[3 x4],
    y5==a0+a1 Cos[x5]+b1 Sin[x5]+a2 Cos[2 x5]+b2 Sin[2 x5]+a3 Cos[3 x5]+
        b3 Sin[3 x5],
    y6==a0+a1 Cos[x6]+b1 Sin[x6]+a2 Cos[2 x6]+b2 Sin[2 x6]+a3 Cos[3 x6]+
        b3 Sin[3 x6],
    y7==a0+a1 Cos[x7]+b1 Sin[x7]+a2 Cos[2 x7]+b2 Sin[2 x7]+a3 Cos[3 x7]+
        b3 Sin[3 x7]}, {a0, a1, b1, a2, b2, a3, b3}]
---------------------------------

Might there be a more straightforward solution? The sinus and cosinus terms evidently are fixed, so....

Gratitude beyond expression,

--
Arthur Fritzsche             |                PowerPC advocate since 11/04/79
afritzse at limmat.ch           |    OS/2 forever! UNIX forever! Win 95 forever!
                        ---({|})---
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CIS: 100031,1752             |      on Grand Friesenberg, Zurich, Switzerland
   *** Drop by at http://www.limmat.ch/afritzse/ -- MARVELLOUS nature! ***




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