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MathGroup Archive 2006

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Re: system of nonlinear equations in mathematica?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72288] Re: system of nonlinear equations in mathematica?
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Mon, 18 Dec 2006 06:56:11 -0500 (EST)
  • Organization: The Open University, Milton Keynes, UK
  • References: <em3a4g$7f0$1@smc.vnet.net>

pilly4u wrote:
> Hai all,
> 
> I am tryign to solve a system of nonlinear differential equations using mathematica.I think there exists singularity in my equations and am new to mathematica and donoy know i to get the problem resolved.Please help me out in this.thought to attach my equations here which i couldnt do.please do reply me through email to saihone at gmail.com.
> 
> 0.5(derivative(f)+x(derivative(derivative(x))= - derivative(0.1*k^2/d(derivative(derivative(f))));
>  
> -10(k+0.5*x*derivative(k)) = derivative(0.1*k*k*derivative(k)/d) + 0.1*k^2*(derivative(derivative(f))^2/d - d;
> 
> 10(-2d-derivative(d)*x/2) = derivative(0.1*k^2*derivative(d)/d) + 0.144*k*(derivative(derivative(f))^2) - 1.92*d^2/k
> 
> the code i wrote is 

It would be much much better to post your code in InputForm: select the 
cell(s) you want to include in your email and go to Menu Cell -> Convert 
  To -> InputForm

Or you could use the excellent Ingolf Dahl's "SetFaceAndFont" palette. 
See http://library.wolfram.com/infocenter/MathSource/5752/

> \!\(\*
>   RowBox[{\(eqdiff1 = 10\/2\ \(f\^â?²\)[x] + \(10\/2\) \(xf\^â?³\)[x] == \(f\^3\)[
---------------------------------------------------------^^
It seems a space is missing here. I guess you wanted the variable x 
times the second derivative of the function f; however, as written you 
declare a new function called xf.

<snip>


Regards,
Jean-Marc


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