ode45 second order

please, I want to plot second order and use function ode45. So just now I can't write function.

y" = 3.6sin(t) - 60y - 5y'

and this is my question 👆👆

function dy=model(t,y)
dy = [y(2); 3.6*sin(t) - 60*y(0) - 5*y(1)]
end

and this 👆👆 is my error function

Answer 1

[Alan Stevens]

Matlab indices start at 1, so you want

dy = [y(2); 3.6*sin(t) - 60*y(1) - 5*y(2)];

[pattara tangjareansuk]

how can i add sin input to this order

[Alan Stevens]

"how can i add sin input to this order"

I'm not sure what you mean. Your second order ode already has 3.6*sin(t) as a forcing function. Do you mean you want to add another term to the forcing function e.g.

y'' + 5*y' + 60*y = 3.6*sin(t) + 2*sin(2*t)

If so, then just make

 dy = [y(2); 3.6*sin(t) + 2*sin(2*t) - 60*y(1) - 5*y(2)];

[pattara tangjareansuk]

i want to create system identification . my professor he said "you should create analytical solution and compare between lsim