i wanted to know how to do initial value problem with step function using matlab

for example: D^3x-Dx= 1 for t<2 =0 for t >=2 having x(o)=x'(0)=x''(0)=0

I know the basic of laplace in matlab like using syms t s x and using dsolve method to solve but dont know how to write this togther with step function to get final answer..

Answer 1

[Azzi Abdelmalek]

Look at this example d2y/dt+2dy/dt+3y=4*dx/dt+6x

N=[4 6],
D=[1 2 3];
model=tf(N,D)   % your transfer function
t=0:0.1:100;     % your time vector
[y,t]=step(model,t)
plot(t,y)

You can also use lsim command for any input