Non Linear DE solving using ODE45

I am trying to solve a non linear differential equation which is df/dt=-.3223+(1/9)*(175.9384/f) through using this command :

dfdt=@(t,f) -.3223+(1/9)*(175.9384/f);

[tv,fv]=ode45(dfdt,[0 5],59.9581);

plot(tv,fv)

Why i am getting linear plot here?

Answer 1

[David Goodmanson]

Hi Muhammad,

with that set of constants, the time has not been run out far enough to see the final result. Try changing the time limits to, say, [0 2000]. Then you can see f approach its asymptotic value (df/dt = 0) of

175.9384/(9*.3223)
ans = 60.6538

[Muhammad Rashedul Alam Chowdhury]

Thank you. :)