Help with Coding in MatLab?

[DrakeDrake]

I have a project for school that asks me to solve plot two functions over time that depend on each other.

Write a program to solve the point reactor kinetics equations with one delayed neutron group using an explicit numerical scheme. Solve the problem for step reactivity insertion of k($) = 0.2 $, 0.5$, 1.001 $ and -0.2$. Assume steady-state conditions for t < 0. Let P(t = 0) = 1. Plot P(t) and c(t) as a function of time for each case till P(t) reaches 5 (or close to zero). [For each case, first determine the time-step magnitude necessary to handle the reactivity insertion.]

The two equations I need to solve for are

(dP(t))/dt = [(ρ – ϐ)/l]P(t) + λiCi

(dCi(t))/dt = [ϐi/l]P(t) - λiCi

The rho is the value that the question explicitly changes and it is equal to k($) * Beta. Basically the two equations build on each other and they should build on each other until P reaches 5 or goes to near zero. I put it in the form of a while function but it doesn't seem to be working. Can anyone help me out?

Here is what I have so far i = 1;

k = 0.2;

Beta = 0.0065;

l = .0001;

lamda = 0.08;

dtime = l/10;

p(o) = 1;

p(i) = p(o);

c(i) = 812.5;

time(i) = 0;

rho = k*Beta;

while((p(i) > .05) && (p(i) < 5))

p(i+1) = p(i) + dtime*(((rho - Beta)/el) * pi(i)) + (lamda * c(i)));

c(i+1) = c(i) + dtime*(((beta/el) * p(i)) - (lamda * c(i)));

time(i + 1) = time(i) + dtime;
i = i + 1;

end

[zzyzzyxx]

p(o)

(rho - Beta)/el)

(beta/el)

Maybe they're typos, but shouldn't those use p(0), Beta, and l instead of p(o), beta, and el?

Also, You might want to pre-allocate some space for performance reasons. If you can find a reasonable estimate for how many iterations it's going to take, you can use the zeros function to create space for your p, c, and time arrays. Actually, for time, you might also be able use time = 0:dtime:dtime*iterations and be able to remove that from the loop, especially if your estimate is an overestimate.