Using Matlab - plotting frequency responses

[Rareform]

Homework Statement

I am asked to plot the log magnitude and phase of the frequency response 1 + 1/2*e^(-j*omega). I am told to use the freqz function for this problem. I have tried using the help freqz feature in Matlab but I haven't been able to work it out.

Homework Equations

H(e^(j*omega) = 1 + 1/2*e^(-j*omega)

H(e^(j*omega) = (e^(j*omega) + 0.5)/(e^(j*omega))

The Attempt at a Solution

omega=linspace(0,pi,1024);
[H,W] = freqz(0.5,1,512);
subplot(2,1,1);
plot(omega,abs(H))
title('Log Magnitude (6.39a)');
subplot(2,1,2);
plot(omega,angle(H))
title('Phase (6.39a)');

 

[ganondorf29]

Does this help at all?

http://www.mathworks.com/help/toolbox/signal/freqz.html