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Topic: Non-linear System of Equations
Replies: 1   Last Post: Jan 2, 2013 10:44 AM

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Alan Weiss

Posts: 1,267
Registered: 11/27/08
Re: Non-linear System of Equations
Posted: Jan 2, 2013 10:44 AM
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On 1/2/2013 6:01 AM, Yasser wrote:
> Hello, EveryBody
>
> I want to solve the following nonlinear system of equations:
>
> eq1='m=10 '; eq2='k=20 '; eq3='cp=30 '; eq4='ro=40 ';
> eq5='dc=0.18 ';
> eq6='dsi=0.5 ';
>
> eq7='pr=m*cp/k';
> eq8='RaDc=((2*9.8*((ro)^2)*(dc^3)*(pr))/((m)^2))*((Tc-Tg)/(Tc+Tg))';
> eq9='Nui=((0.649*(1+(0.559/(pr))^(0.6)*(RaDc)^(1/4))^(-5/12))^(15)+(0.12*(RaDc)^(1/3))^(15))^(1/15)';
>
> eq10='Nuc=2/log(1+2/(Nui))';
> eq11='hc=k*Nuc/dc';
> eq12='RaDsi=(2*9.8*((ro)^2)*(dsi^3)*(pr)/((m)^2))*((Tg-Ts)/(Tg+Ts))';
> eq13='G=((1+0.6/(pr)^0.7)^(-5)+(0.4+2.6*(pr)^0.7)^(-5))^(-1/5)';
> eq14='Ndusi=((0.587*(G)*(RaDsi)^0.25)^(15)+(0.12*(RaDsi)^0.25)^(15))^(1/15)';
> eq15='Nusi=-2/log(1-2/(Ndusi))';
> eq16='hsi=k*Nusi/dsi';
>
> eq17='Ac=22*dc/7'; eq18='Asi=22*dsi/7';
> eq19='33.7-(hc*Ac*(Tc-Tg))=0.001';
> eq20='(hc*Ac*(Tc-Tg))-(hsi*Asi*(Tg-Ts))=0.001';
> eq21='(hsi*Asi*(Tg-Ts))-(482.44322353*(Ts-35))=0.001';
>
> The solution must give the values of Tg, Tc and Ts.
> So any help??!!!
>
> I tried to solve them by SOLVE command but NO ANSWER.
>
> Thanks


I suggest that you try using fsolve from Optimization Toolbox to get a
numeric answer.

Alan Weiss
MATLAB mathematical toolbox documentation



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