solving ordinary differential equations

Hello, I'm a beginner in matlab. I'm trying to solve ODE in matlab, but I'm getting error I don't know why!

This is the equation d2y(t) / dt2 + 2 dy/dt + 5 y(t) = 5 cos1500t, I attached a photo of my code with the errors.

[Torsten]

Which MATLAB version do you use ?

The syntax for using "dsolve" has changed in the course of time.

Answer 1

[Cris LaPierre]

I think the reason for the error is that you have defined dy as a sym variable rather than a symfun, so it is interpretting the '(0)' to be an index into variable dy rather than dy at t==0.

Try this

syms y(t)

dy(t) = diff(y(t),t)

dy(t) = 

dy2(t) = diff(y(t),t,2)

dy2(t) = 

equation = dy2 + 2*dy + 5*y(t) == 5*cos(1500*t)

equation(t) = 

i1 = y(0) == 0;
i2 = dy(0) == 0;

dsolve(equation,[i1,i2])

ans =