Attempted to access 2 element of data dxdt. The valid index range is 1 to 1 Please note that the simulation will be aborted immediately after you continue from this breakpoint to avoid segmentation violations. debug>>

I´m working with opc in simulink, i need to solve the equation:

function [X, dxdt]=Biomassprediction(O2)

%Guardar memoria dxdt=zeros(); t=zeros(); X=zeros();

%Parametros Fair=2.0; Vol=250; %Volumen inicial O2ini=20.76; %Concentración inicial de O2

%Condiciones iniciales X(1)=8.3;%Biomasa residual g/L dxdt(1)=((20.97-O2ini)*100000*Fair*0.001429*0.921*60)/((Vol*100)-(X(1)*0.0006913*60));

tsim=inf; dt=0.01; t(1)=0; i=1;

while t(i)<tsim dxdt(i+1)=dxdt(i)+((20.97-O2)*100000*Fair*0.001429*0.921*60)/((Vol*100)-(X(i)*0.0006913*60))*dt; X(i+1)=X(i)+dxdt(i)*dt;

t(i+1)=t(i)+dt; i=i+1; end

but, i´m getting problems with the solution.