How to plot nullcline in matlab?

Hi guys, I need to plot a set of ODEs' nullclines,

dL/dt = beta*Lext*Y-gamma*L;

dY/dt = delta+kfeed*L^4/(Kmfeed+L^4)-sigma*Y

 here is my code:

beta=1; gamma=1; delta=0.2; Kmfeed=20; kfeed=2; sigma=1; Lext=2;

nullclineL=@(L)gamma.*L/(beta*Lext);

nullclineY=@(L)delta/sigma+kfeed.*L.^4/(sigma*(Kmfeed+L.^4));

L=1:.1:20;

figure(3)

plot(L,nullclineL(L),'b','LineWidth',2); hold on;

plot(L,nullclineY(L),'r','LineWidth',2);

the question is that i cannot get the second plot result, but i don't know what is wrong with that？ Thanks for reading and possible help.

but I don't don't know why i cannot get the second plot reslut,

Answer 1

[John D'Errico]

It seems like you understand the need for .^ operators here. So why have you not chosen to use ./ when appropriate? (The .* operator can also be valuable, but it is not the problem here.)

Think about my question, then look at this line of code, as written by you:

nullclineY=@(L)delta/sigma+kfeed.*L.^4/(sigma*(Kmfeed+L.^4));

[wenjie qian]

thank you so much!!! It does work out!