I have the following code:

b = [4 7 9];

a = [1];

% Create the impulse signal impulse =

[1, zeros(1, 999)];

% Filter the impulse signal

h = filter(b, a, impulse);

% Plot the impulse response figure;

plot(h); title('Impulse Response');

xlabel('Sample Index'); ylabel('Amplitude');

How would I modify this code to include the output of the filter if the input is a DC signal of amplitude 4.

as well as :

. Apply the z transform to the filter and determine the transfer function of the filter.