discrete time histories generation

how can I generate discrete time series? for part C (image below) this is my attempt:

omega  = sqrt(2);
zeta   = 1/sqrt(2);
sympref('AbbreviateOutput', false);

syms x(t) y(t) u
eqn    = diff(x, 2) + 2*zeta*omega*diff(x) + (omega^2)*x == (omega^2)*u;
[V, S] = odeToVectorField(eqn)


A = [0 0; -2 -2];
B = [2; 0];
C = [1 0];
D = 0;
sys = ss(A, B, C, D)

However, for part D, not sure what would be a right approach? Any help will be greatly appreciated. Thanks much.