Initial Plot of a State-Space System

Hello my professor gave me a State-space system and want me to plot initial response via initial(sys,x0,Tfinal) function. Problem is in the question there is only A matrix is given. When I try to plot with only A matrix it gives empty plot. When I try it with made up C matrix it gives a plot. I need to do plot with only A matrix. I would be appreciated if you could help me out.

Matlab Code:

a = [0, 1; -1, 0];
x0 = [1 ; -2];

sys = ss(a,[],[],[]);
initial(sys,x0) 

Answer 1

[Ameer Hamza]

The response of a state-space model with matrix C does not make any sense. I guess the professor wanted to make matrix C as identity matrix. try this

c = eye(2);
a = [0, 1; -1, 0];
x0 = [1 ; -2];
sys = ss(a,[],c,[]);
initial(sys,x0) 

[Taha Erkam Orhan]

Thanks for the answer.

[Ameer Hamza]

I am glad to be of help.