I want to integrate froma function

function prob7f=xequil(x,cao,ep,k2,kc,Fao)

ca=cao*(1-x)./(1+ep*x);
cb=cao*(1-x)./(1+ep*x);
cc=2*cao*x./(1+ep*x);
ra=-(k2*(ca-(cb*cc)./kc));
prob7f=Fao./(-ra);
end

z=@xequil;
volpfreq=integral(z,0,xf);
>> Jallohw5p7
Not enough input arguments.

Error in xequil (line 3)
ca=cao*(1-x)./(1+ep*x);

Error in integralCalc/iterateScalarValued (line 314)
                fx = FUN(t);

Error in integralCalc/vadapt (line 132)
            [q,errbnd] =
            iterateScalarValued(u,tinterval,pathlen);

Error in integralCalc (line 75)
        [q,errbnd] = vadapt(@AtoBInvTransform,interval);

Error in integral (line 88)
Q = integralCalc(fun,a,b,opstruct);

Error in Jallohw5p7 (line 32)
volpfreq=integral(z,0,xf);

All other varables are defined, except x of course, which is the variables I want to solve for.

[Ameer Hamza]

What are values of cao,ep,k2,kc,Fao? Where are they defined? You need to define them inside the function.

[Rodrigo Blas]

%%Data 
T1=50+273.15;              %%k
T2=127+273.15;             %%k
Fao=2.5;            %%mol/min
P=10;               %%atm
k1=10^-4;           %%min^-1
R=8.314;       %j/k*mol
R1=8.206*10^-5*1000;         %%atm*dm^3/K*mol
E=85*1000;                  %%j/mol
kc=.025;            %%mol/dm^2
alpha=.001;       %%dm^3
t=3*60;             %%min
Nao=450;
xf=.90;
xo=0;

%%Calculated Data 
k2=k1*exp(E/R*(1/T1-1/T2)); %%min^-1
cao=P/(T2*R1);          %%mol/dm^3
ep=2+1-1;
xe=jallohw5p7f(cao,ep,kc,xo);
xfe=xe*.9;

pfrxeq=@xequil;

volcstr=(Fao*xf)*(1+ep*xf)/(k2*cao*(1-xf)); %%dm^3
fun=@(x) Fao/(cao*k2)*(1+ep*x)./(1-x);
z=@xequil;


%%funeeqpfr=@(x) Fao/(-ra);
volpfreq=integral(z,0,xf);
volpfr=integral(fun,0,xf);                  %%dm^3 
t=3*60;
Nao=450;
v7e=Nao/(t*k2*cao)*log(1/(1-xf));
[x,y]=ode45(@(x,y) jallohwfun7(alpha,ep,y,cao,k2,Fao),[0 500],[1 0]);
%%funeq=@(x) Fao./(-(k2*cao/(1+ep*x)*((1-x)-(4*cao^2*x^3)/((1+ep*x)^2)*kc)));
%%volpfreq=integral(funeq,0,xf);

plot(x,y(:,1),'r','LineWidth',1);
      hold on;
      plot(x,y(:,2),'k','LineWidth',1);
      legend('Pressure', 'Conversion');
      xlabel('Volume [dm^3]');
      ylabel('Pressure [atm] & Conversion');
      title('Pressure and Conversion vs Volume ');

Here is my whole script..

Really? I cant pass them through the function?

Answer 1

[Ameer Hamza]

The integral function should be called like this

z=@(x) xequil(x, cao, ep, k2, kc, Fao);
volpfreq=integral(z,0,xf);

Also change the following line in the function xequil

ra=-(k2*(ca-(cb*cc)./kc));

with

ra=-(k2.*(ca-(cb.*cc)./kc));

[Rodrigo Blas]

function prob7f=xequil(x,cao,ep,k2,kc,Fao)

ca=cao*(1-x)./(1+ep*x);
cb=cao*(1-x)./(1+ep*x);
cc=2*cao*x./(1+ep*x);
ra=-(k2.*(ca-(cb.*cc)./kc));

prob7f=(Fao/(-ra));
end

z=@(x) xequil(x,cao,ep,k2,kc,Fao);
volpfreq=integral(z,0,xf);



>> Jallohw5p7
Error using  / 
Matrix dimensions must agree.

Error in xequil (line 8)
prob7f=(Fao/(-ra));

Error in Jallohw5p7>@(x)xequil(x,cao,ep,k2,kc,Fao)

Error in integralCalc/iterateScalarValued (line 314)
                fx = FUN(t);

Error in integralCalc/vadapt (line 132)
            [q,errbnd] =
            iterateScalarValued(u,tinterval,pathlen);

Error in integralCalc (line 75)
        [q,errbnd] = vadapt(@AtoBInvTransform,interval);

Error in integral (line 88)
Q = integralCalc(fun,a,b,opstruct);

Error in Jallohw5p7 (line 30)
volpfreq=integral(z,0,xf);

This is the new error I get

[Ameer Hamza]

You also changed the last line

prob7f=(Fao/(-ra));

change it back to

prob7f=(Fao./(-ra));