def analitInitial((A, B, C, D), x0, T):
    T = arange(T[0], T[1], T[2])
    x0 = array(x0)

    J, V = eig(A)
    J = mt(J * eye(3, 3))
    S = mt(V)
    y = ([], [])

    for i in range(len(T)):
        y[0].append(T[i])
        yy = C * S * mt(expm(J * T[i])) * mt(inv(V)) * mt(x0).transpose()
        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()