Solving System of Equations - Complex

I want to solve a system of equatoins. It is resulting an empty structure. Any help would be greatly appreciated!

I want to solve for: xco2, xco, xo2, xo

With these 4 unkowns I have the following 4 equations:

kp1 = (xo2^(1/2) * p^(1/2)*xco) / xco2

kp2 = (xo^2*p) / xo2

1 = xco2 + xco + xo2 + xo

1/2 = (xco2 + xco) / (xco + xo + 2*xo2)

Here is the following code:

% these are just some arbitrary values I chose for kp1, kp2, and p to see if solutoins could be solved for

kp1 = 2;
kp2 = 3;
p   = 1;

syms xco2 xco xo2 xo

equation1 = (1/kp1)*((xo2^(1/2)* p^(1/2)*xco) / xco2);
equation2 = (1/kp2)*((xo^2*p) / xo2);
equation3 = xco2 + xco + xo2 + xo - 1;
equation4 = 2*((xco2 + xco) / (xco + xo + 2*xo2));

sol = solve(equation1,equation2,equation3,equation4, 'xco2 > 0', 'xco > 0'...
    ,'xo2 > 0', 'xo > 0');

When I type in "sol.xco" or any of the other symbols I am trying to solve for I get an empty structure which I can not explain. Any help would be greatly appreciated!

Answer 1

[KSSV]

Try this:

kp1 = 2;
kp2 = 3;
p   = 1;

syms xco2 xco xo2 xo

eqns = [(xo2^(1/2)* p^(1/2)*xco)/xco2 == kp1, 
        (xo^2*p)/xo2 == kp2, 
         xco2 + xco + xo2 + xo == 1,
        (xco2 + xco)/(xco + xo + 2*xo2) == 1/2] ; 
sol = solve(eqns,[xco2, xco, xo2, xo])

[Articat]

This works great! I guess I didn't realize that I could insert the equation with a double equals. In the solution I get a value "z". any idea what that is? I didn't initalize any z value in the initial code. Perhaps some value to help solve the equatoin??

[KSSV]

Try

double(sol{1}.xco2)
double(sol{1}.xco)
double(sol{1}.xo2)
double(sol{1}.xo)

[Articat]

I get a "Cell contents reference from a non-cell array object." error.

Perhaps I could put the equations into cell format?? I am not super familiar with cell formats but could give it a try.

[KSSV]

Okay.....actually I have octave and answering through that..I have no access to MATLAB. Might be sol is a structure.

Try sol.xo..etc.