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Re: making a e-funtion of two coördinates

• To: mathgroup at smc.vnet.net
• Subject: [mg31646] Re: making a e-funtion of two coördinates
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Fri, 23 Nov 2001 05:46:12 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <9t86cv$r6l$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

y==U*Exp[a*t]

is for real values

Log[y]==Log[U]+a*t

an linear function of Log[y]. You can 
determine Log[U] and a for Fit[]

Regards
  Jens

TheSquaredBun wrote:
> 
> 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