# How to solve an ODE with three equation that are dependent on each other

3 views (last 30 days)
Pipe on 19 Oct 2022
Edited: Torsten on 19 Oct 2022
I have these equations that are supposed to tell me how the concentration of C changes over time. I am trying to use ODE 45 but I keep getting error
v1=0.3;
k2 = 0.3; %constant
C = v1-dpdt; %ODE for network
dpdt = k2*C; %Rate of equation
for tspan = 0:100
dpdt = @(PEP,t) (k2*C*t)
[PEP, t] = ode45(dpdt,tspan,0)
end
Torsten on 19 Oct 2022
Edited: Torsten on 19 Oct 2022
Please write down the differential equation(s) you are trying to solve in a mathematical notation since your code doesn't make sense.

Star Strider on 19 Oct 2022
Some of this is difficult to interpret.
My best guess at a solution —
v1=0.3;
k2 = 0.3; %constant
C = v1;
% C = v1-dpdt; %ODE for network
% dpdt = k2*C; %Rate of equation
tspan = 0:100;
dpdt = @(PEP,t) (k2*C*t);
[t,PEP] = ode45(dpdt,tspan,k2);
figure
plot(t,PEP)
grid
xlabel('t')
ylabel('PEP') Make appropriate changes in case my guess is in error.
.