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MathGroup Archive 2006

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Re: Solve Equation involving Error Function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg65217] Re: Solve Equation involving Error Function
  • From: Roland Franzius <roland.franzius at uos.de>
  • Date: Sat, 18 Mar 2006 06:40:39 -0500 (EST)
  • Organization: Universitaet Hannover
  • References: <dvdih3$a3a$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

rajanikanth at gmail.com schrieb:
> hi!
> 
> Could somebody tell me how to solve this equation for the value of k in
> Mathematica
> 
> t2-t1*Erfc[0.0005/Sqrt[k]] ==0
> 
> where t2 is a list given by {87,87,87}
> and t1 is a list given by  {81,80,80}

Assuming you want to solve for three independent values of k  map the 
Solve operator into the list of equations and replace Sqrt[k] by k1

sol=First/@Map[Solve[# == 0, k] &, {87, 87, 87} - {81, 80, 80} 
Erfc[0.0005/k1]]

    {{k1 -> -0.0076056}, {k1 -> -0.00643493}, {k1 -> -0.00643493}}

Unless you have a wrong sign or swapped t1 and t2 there is no real 
solution for k=k1^2.

-- 

Roland Franzius


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