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MathGroup Archive 2001

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AW: making a e-funtion of two covrdinates

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31641] AW: [mg31617] making a e-funtion of two covrdinates
  • From: Matthias.Bode at oppenheim.de
  • Date: Fri, 23 Nov 2001 05:46:05 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hello Roderik,

plug in your y and t values and try:

 \!\(InputForm\`\(y1 = 2\n
  y2 = 5\n
  t1 = 1\n
  t2 = 7\n
  Solve[{y1 == u\ \[ExponentialE]\^\(a\ t1\), 
      y2 == u\ \[ExponentialE]\^\(a\ t2\)}, {u, a}]\)\)

By the way, MATHEMATICA uses the widely accepted value of 2.71828..... for
Euler's Number "e".

Best regards,

Matthias Bode
Sal. Oppenheim jr. & Cie. KGaA
Koenigsberger Strasse 29
D-60487 Frankfurt am Main
GERMANY
Tel.: +49(0)69 71 34 53 80
Mobile: +49(0)172 6 74 95 77
Fax: +49(0)69 71 34 95 380
E-mail: matthias.bode at oppenheim.de
Internet: http://www.oppenheim.de







Gesendet: Sonntag, 18. November 2001 12:29
An: mathgroup at smc.vnet.net
Betreff: [mg31617] making a e-funtion of two covrdinates



I have got two coordinates out of graph. The line through the
coordinates could be described as:

y = U * e^(a * t)

(e is Exponetial e (approx. 2.37))

t is the x-value, I have give two points (t1,y1) and (t2,y2)

I have tried several things (Solve and Fit for example), but I can't
get the function.
Does anyone know what should be the input to let Mathematica solve the
a and U in the formula.

Much thanks in advance,

Roderik
r.f.emmerink at st.hanze.nl 


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