MATLAB: What’s wrong with the folow function

differential equationserroreuler's method

I made a function in order to calculate a system of differential equations. I'm using Euler's method.
i=0;                           
C= 1;                          % Reagent's initial concentration
T=15;                          % Initial temperature 
dC= -exp(-10/T+273)*C;
dT= 1000*exp(-10/(T+273))*C-10*(T-20);
h = 4;                         
ti = 0;                        % time=0
tf = 8;                        % end time of the simulation 
niteracoes = round((tf-ti)/h); % number of steps 
vC= zeros (niteracoes);
vT= zeros (niteracoes);
for i = 1:niteracoes                 
C(i+1) = C(i) - h*dC(i,i);     % Euler's method

T(i+1) = T(i) - h*dT(i,i);     % Euler's method
ti = ti + h;                   % Increment time
vC(i)=C(i+1);
disp(vC)
vT(i)=T(i+1);       
disp(vT)      
i=i+1;                               
end
Error in euler (line 16) C(i+1) = C(i) – h*dC(i,i);

Best Answer

You start dC as a single element, and you do not expand it in your "for" loop, so it does not have two elements by the time "i" becomes 2.
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