Help with maths / programming

Neewbie_noob

Hi,
I have a college assignment due on Friday, and I am having issues with it. Help would be great. Cheers.

Basically, I am given 3 different differential equations for the spreading and regression of a disease and birth rates, recovery rates and infection rates.
It is assumed that people who recover from the disease have permanent immunity and the birth rate stops the disease from dying out.

dy1/dt=i*Y1*Y2-(r*Y1);
dy2/dt=-i*Y1*Y2+b*(Y1+Y2+Y3);
dY3/dt=r*Y1;

i=0.000006; %infection rate%

r=0.05; %recovery rate, those who have recovered are assumed to be immune indefinitely%

b=0.00005; %birth rate, birth of children prevents the extinction of the disease%4

Y1=300; %people who can ransmit the disease%

Y2=30000; %People who can catch it%

Y3=400000; %People who have recovered, it can be assumed the permanent immunity results from recovery%

%Y3 should not apppear in the second differential equation%

I plan to integrate dy3/dt and stick it into the second equation.

I was told that I should get an exponential graph, but can't do it ...


here's my script so far. Thanks for reading all this and thanks for the help.

%Epidemics%

dy1/dt=i*Y1*Y2-(r*Y1);
dy2/dt=-i*Y1*Y2+b*(Y1+Y2+Y3);
dY3/dt=r*Y1;

i=0.000006; %infection rate%
r=0.05; %recovery rate, those who have recovered are assumed to be immune indefinitely%
b=0.00005; %birth rate, birth of children prevents the extinction of the disease%4
Y1=300; %people who can ransmit the disease%
Y2=30000; %People who can catch it%
Y3=400000; %People who have recovered, it can be assumed the permanent immunity results from recovery%

%Y3 should not apppear in the second differential equation%

IT HAS TO BE DONE IN MATLAB BTW

Pembily

I didn't read this properly initially, and didn't realise you wanted the programme created for you.

This is your college assignment, you can ask for help, but not ask people to do. No one has any suggestions so I am locking the thread.

Don't post the same topic again.