def analitStep((A, B, C, D), T):
    ss = StateSpace(A, B, C, D)

    T = arange(T[0], T[1], T[2])
    J, V = eig(A)
    J = mt(J * eye(3, 3))
    V = mt(V)
    y = ([], [])
    for i in range(len(T)):
        y[0].append(T[i])
        yy = C * V * mt(expm(J * T[i]) - eye(3, 3))* mt(inv(J)) * mt(inv(V)) * B
        y[1].append(array(yy[0])[0][0])
    plot(y[0], y[1])
    title('Analytical construction')
    xlabel('t, s.')
    ylabel('y(t)')
    grid(color='g', linestyle='--')
    show()