Hi guys, I need to solve this 3rd order ODE:

?⃛+2??̈+3??̇+4??=2, t≥0, ?̈(0)=?̇(0)=?(0)=0

This is my script:

[t,y] = ode45(@diffeq3,[0 50],[0;-1;1]);

plot(t,y)

function dy = diffeq3(t,y)

if t >= 0

dy(3) = 0

dy(2) = 0

dy(1) = 0

end

dy = zeros(3,1);

dy(1) = y(2);

dy(2) = y(3);

dy(3) = 2 – 2*y(3) – 3*y(2) – 4*y(1);

end

Did I do it right?

I got two questions, I got three curves which on is which?

And did I define t≥0, ?̈(0)=?̇(0)=?(0)=0 correct? With:

if t >= 0

dy(3) = 0

dy(2) = 0

dy(1) = 0

Thanks in advance for the help!

## Best Answer