Multiple Equations Solver Problem

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Alexander
Alexander on 24 Nov 2014
Answered: Alexander on 24 Nov 2014
All variables are known except c, Prise, Treflection and Pabs
syms c
Treflection = 2*L_drivepipe/c;
Prise = c*rho*V_crit*Treflection/Taction;
Pabs = Pstat_closing + Prise;
if (Air_in_Account == false)
eq1 = c == sqrt(1/(rho*(1/Ev_water+(s)*D_drivepipe/EYoung/Thick_drivepipe)));
else
eq1 = c == sqrt(1/(rho*(cv1/Ev_water+cv2/gamma/Pabs+ (s)*D_drivepipe/EYoung/Thick_drivepipe)));
end
[c] = solve(eq1,c);
c = eval(c);
Prise = eval(Prise);
Pabs = eval(Pabs);
Treflection = eval(Treflection);
Matlab calculates values for Pabs and Prise. But does not give a value for c while actually Pabs and Prise are functions of c. I know that we can solve back to know the value of c out of the result of Pabs or Prise but that doesn't seem good programming to me. Making a set of equations was also an option but my matlab only returned a matrix with the variables in it without values. Can someone help?
This is an easy solve situation and I can't understand that since a week my matlab is unable to give good outputs.
Thanks in advance, A

Accepted Answer

Alexander
Alexander on 24 Nov 2014
I installed matlab again and now it works fine.

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