Fsolve Error! Need help- Using Fsolve to solve system of non-linear equations.

% ***Function script

cpa=1.005;
cpg=1.148;
Qin=801.4;
t2=401;
t1=294.11;
p1=101.4;
p2=2.5*p1;
px=p2;
p3=.94*px;
p5=p1;
nreg=.8;
nc=.82;
nt=.85;
function F=myfun(x)
F=[x(10)-cpa*(t2-t1);
    x(10)-cpg*(x(2)-x(3));
    x(9)-cpg*(x(3)-x(4));
    Qin-cpg*(x(2)-x(1));
    nreg*(x(4)-t2)-(x(1)-t2);
    nc*(t1-t2)-(t1-x(5));
    nt*(x(2)-x(6))-(x(2)-x(3));
    nt*(x(3)-x(7))-(x(3)-x(4));
    x(5)-(2.5^(.28571429)*t1);
    x(6)-((x(8)/p3)^(.24981245)*x(2));
    x(7)-(p5/x(8))^(.24981245)*x(3)];
end
% ****Solver Code
x0=[440;1000;900;850;380;890;800;160;110;110];
options = optimoptions('fsolve','display','iter');
[x,fval]= fsolve(@project2,x0,options);

[madhan ravi]

picture is useless , upload your actual code not pictures!

[Collin Pautsch]

I added them as attachments once I realized the pictures were unreadable.

[Collin Pautsch]

I did now

Answer 1

[madhan ravi]

Make the below changes in your code:

[x,fval]= fsolve(@(x)myfun(x,cpa,cpg,Qin,t2,t1,p1,p2,px,p3,p5,nreg,nc,nt),x0,options);
function F=myfun(x,cpa,cpg,Qin,t2,t1,p1,p2,px,p3,p5,nreg,nc,nt)

Note: You finally get a message that No solution found. Maybe it has something to do with the initial guess but this answer clears all the errors in your code. You would have to figure it out by yourself.

[Collin Pautsch]

thanks, I'll mess with the inital guesses

[Collin Pautsch]

Is there a way to use constraints along with the Fsolve function?

[madhan ravi]

Sorry, I'm not familiar with that.

Answer 2

[Alex Sha]

Hi， your equations seems to be Contradictory:

"nc*(t1-t2)-(t1-x5)" lead to x5=381.7598

while "x5-(2.5^(.28571429)*t1)" lead to x5=382.126307902248

it is why you can not get accurate solution.