MATLAB: Error message when trying ot integrate

integral

To     = 27 + 273.15;                  % C
vo     = 2;                            % dm^3/s
cao    = 0.1;                          % mol/dm^3
k1     = .01;                          % dm^3/mol*s
tha    = 1;
thb    = 1;
ha     = -20000; hb=-15000; hc=-41000; % cal/mol

cpc    = 30;cpa=15;cpb=15;             % cal/mol*k

sumtcp = tha*cpa+thb*cpb;
delcp  = cpc-cpb-cpa;
dhrx   = hc-hb-ha;
E      = 10000;                        % cal/mol
R      = 1.987;                        % cal/mol*k
x1     = .85;
ca     = cao*(1-x);
cb     = cao*(1-x);
cc     = cao*x;
fao    = cao*vo;
%%CSTR VOLUME
T      = To+(-dhrx)*x/((sumtcp)+delcp*x) ;
k      = k1*exp(E/R*(1/To-1/T));
ra     = -(k*(cao)^2*(1-x)^2);
vcstr  = fao*x/(-ra);
%%PFR Vol
fun    = @(x) fao/(-ra);
>> vpfr=integral(fun,0,x1)
Error using integralCalc/finalInputChecks (line 526)
Output of the function must be the same size as the
input. If FUN is an array-valued integrand, set the
'ArrayValued' option to true.
Error in integralCalc/iterateScalarValued (line 315)
                finalInputChecks(x,fx);
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);
 
>>
I keep getting this error message. Not sure how to fix

Best Answer

Try this code and compare it with your code to see the issues.
To=27+273.15;  %%C
vo=2;   %%dm^3/s
cao=0.1;    %%mol/dm^3
k1=.01;  %%dm^3/mol*s
tha=1;thb=1;
ha=-20000; hb=-15000; hc=-41000; %%cal/mol

cpc=30;cpa=15;cpb=15; %%cal/mol*k

sumtcp=tha*cpa+thb*cpb;
delcp=cpc-cpb-cpa;
dhrx=hc-hb-ha;
E=10000;                       %%cal/mol
R=1.987;        %%cal/mol*k
x1=0.85;
ca=@(x) cao*(1-x);
cb=@(x) cao*(1-x);
% cc=cao*x;
fao=cao*vo;
%%CSTR VOLUME
T=@(x) To+(-dhrx)*x/(sumtcp+delcp*x) ;
k=@(x) k1*exp(E/R*(1/To-1/T(x)));
ra=@(x) -(k(x).*ca(x).*cb(x));
%%vcstr=fao*x/(-ra);%%
%%PFR Vol
f=@(x) fao./(-ra(x));
vpfr=integral(f,0,x1);
Related Question