Errors while trying to setup equation for root finding.
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I am trying to set up an equation for root finding to find a, however in the code at the bottom i get an error saying Parse error: Parse error at '=' . usage might be invalid syntax. Does anyone know how to fix this? I'd be grateful for any help.
x_pdo = z_pdo/(1 + a(k_pdo - 1));
x_water = z_water/(1 + a(k_water - 1));
x_glycerol = z_glycerol/(1 + a(k_glycerol - 1));
x_pdo + x_water + x_glycerol - 1 = 0;
6 comentarios
Torsten
el 12 de En. de 2022
If you have to insert the first three equations into the last to solve for a, also the x_... are unknown.
Otherwise, you could just pick one of the three equations at the top and solve for a.
Respuestas (3)
James Tursa
el 12 de En. de 2022
Did you mean multiply by the "a"?
x_pdo = z_pdo/(1 + a*(k_pdo - 1));
x_water = z_water/(1 + a*(k_water - 1));
x_glycerol = z_glycerol/(1 + a*(k_glycerol - 1));
Torsten
el 12 de En. de 2022
Editada: Torsten
el 12 de En. de 2022
function main
a0 = 1;
a = fzero(@fun,a0)
end
function res = fun(a)
z_pdo = ...;
k_pdo = ...;
z_water = ...;
k_water = ...;
z_glycerol = ...;
k_glycerol = ...;
res = z_pdo/(1 + a*(k_pdo - 1)) + z_water/(1 + a*(k_water - 1)) + z_glycerol/(1 + a*(k_glycerol - 1)) -1.0;
end
22 comentarios
Walter Roberson
el 16 de En. de 2022
if a is the same as α then α(kj-1) is 0 when α is 0, and 1+0 is 1, so xj = zj/stuff would be xj=zj/1...
Walter Roberson
el 12 de En. de 2022
syms a k_pdo x_pdo x_glycerol z_pdo z_glycerol k_glycerol k_water x_water z_water
eqn1 = x_pdo == z_pdo/(1 + a*(k_pdo - 1));
eqn2 = x_water == z_water/(1 + a*(k_water - 1));
eqn3 = x_glycerol == z_glycerol/(1 + a*(k_glycerol - 1));
eqn4 = x_pdo + x_water + x_glycerol - 1 == 0;
eqns = [eqn1; eqn2; eqn3; eqn4]
sol = solve(eqns, [a, x_pdo, x_glycerol x_water])
sols = [sol.a, sol.x_pdo, sol.x_glycerol, sol.x_water]
sol3 = solve(eqns, [a, x_pdo, x_glycerol x_water], 'maxdegree', 3);
sol3s = [sol3.a, sol3.x_pdo, sol3.x_glycerol, sol3.x_water];
vpa(sol3s)
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