I have a homework assignment that I'm not sure how to do, the professor did not teach us anything about the matlab ode45 function. I have the line of code that I have so far but I'm not sure whats wrong.

function HW1Q3
clear;
clc;
t0 = 0;
tf = 30;
C0= [0 50]; 

soln = ode45(@f, [t0 tf], C0);
t=linspace(0,tf,100);
C1=deval(soln,t,1);
C2=deval(soln,t,2);
plot(t,C1,'-k',t,C2,'-r','LineWidth',2);
xlabel('t');
ylabel('C');
grid on;
title('HW1, Q3')
end

function dCdt = f(t,C)
V = 2;     
q = 0.4;
Ci= 50;
dCdt(1) = -(q/V)*C(1);
dCdt(2) = (q/V)*(Ci-C(2));
dCdt = dCdt';
end

[Torsten]

You only need to solve for C - the exit concentration. Why do you have 2 equations instead of 1 ?

Best wishes

Torsten.

[Mackenzy Allen]

The only example he showed us was with two equations, I have no idea how to go about doing the problem.

Answer 1

[Torsten]

function HW1Q3
clear;
clc;
t0 = 0;
tf = 30;
C0 = 0; 

soln = ode45(@f, [t0 tf], C0);
t=linspace(0,tf,100);
C1=deval(soln,t,1);
plot(t,C1,'-k','LineWidth',2);
xlabel('t');
ylabel('C');
grid on;
title('HW1, Q3')
end

function dCdt = f(t,C)
V = 2;     
q = 0.4;
Ci = 50;
dCdt(1) = (q/V)*(Ci-C(1));
end

[Mackenzy Allen]

Thank you!