I need to plot population growth model with different values of b where b>d and b=d using for loops. Both results should be visible on the same graph with different colors. Here is my function and intial value, but I am not getting how to get the plot . H=@(t,N)[b*N-d*N]; [T,Y]=ode45(H,[0:1:time],[N0]); Intitial value b= 0.1 0.001 d=0.001 N0=400 I need two line for each b on the same plot.

Plot Population growth function with different values of b using fo...

Saira 2023-2-2

编辑：Saira 2023-2-2

As per requirement, I have to use forloop and ODE function. and T should be from 0 to 400. Sorry forget to mention

Torsten 2023-2-2

编辑：Torsten 2023-2-2

在 MATLAB Online 中打开

b = [0.1 0.001];

d = 0.001;

N0 = 400;

time = 400;

hold on

for i = 1:numel(b)

H=@(t,N)[b(i)*N-d*N];

[T,Y] = ode45(H,[0:1:time],[N0]);

plot(T,Y)

end

hold off

grid on

Saira 2023-2-2

Thanks, I was getting the same results.

But when I try an individual plots by putting b=.01, and b=.001. I get the results as attached. and you can see the plots dimentions are totally different. They should be same, either by putting in the seperate function or function inside a loop.

Saira 2023-2-2

Why you are too getting totally different plots for the same function and same inputs?

Torsten 2023-2-2

编辑：Torsten 2023-2-2

Show us the two codes for which you mean you get different results for the same input.

Include them as text here, not as a PNG file.

Saira 2023-2-2

function[T,Y]=model_growth(par,time)

b=par(1);

d=par(2);

N0=par(3);

H=@(t,N)[b*N-d*N];

[T,Y]=ode45(H,[0:1:time],[N0]);

end

Commands: when b=d

par=[0.01 0.01 400];

time=500;

[~,Y]=model_growth(par,time)

plot(T,Y)

and

par=[0.01 0.001 400];

time=500;

[~,Y]=model_growth(par,time)

plot(T,Y)

Torsten 2023-2-2

I don't understand your point.

The parameters are different for the two cases - so the results are different.

Saira 2023-2-2

You are right, I think that was what I was doing wrong. but

par=[0.01 0.01 400];

time=500;

[T,Y]=model_growth(par,time)

plot(T,Y)

This gives a straight line at 400 point when I use it in indivdual function, but at 0 when in a loop. Can you elaborate, what is going on here.

Torsten 2023-2-2

Maybe 400 looks like 0 in the loop plot because the second plot gives such large results for N.

Look at the plot from my code above. The red line looks like 0 because the blue line gets up to about 7e19, but is 400.

Saira 2023-2-2

Thank you so much.

I have just started coding so don't know these subtle changes.

Plot Population growth function with different values of b using for loop

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Plot Population growth function with different values of b using for loop

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