1a.
t = [0:1/8000:1-1/8000];
x = sin(2*pi*800*t);
 sound(x)

1b.
[Ax, Phix] = fourierSeries(x);
frequencies = [0:8000/2];
plot(frequencies, Ax);

2a.
t = [0:1/8000:1-1/8000];
y = sin(2*pi*800*(t.*t));
>> sound (y)
2b.
frequencies = [0:8000/2];
y = sin(2*pi*800*(t.*t));
[Ay, Phiy] = fourierSeries(y);
plot(frequencies, Ay);

3a.
t = [0:1/8000:1-1/8000];
y = sin(2*pi*800*(t.*t));
z = y(8000:-1:1);
sound(z)

3b.
frequencies = [0:8000/2];
[Az, Phiz] = fourierSeries(z);
plot(frequencies, Az);

4a.
t = [0:1/8000:1-1/8000];
y = sin(2*pi*800*(t.*t));
waterfallSpectrogram(y, 8000, 400, 30);
4b.
t = [0:1/8000:1-1/8000];
y = sin(2*pi*800*(t.*t));
z = y(8000:-1:1);
waterfallSpectrogram(z, 8000, 400, 30);

5a.
y = sin(2*pi*800*(t.*t));
specgram(y,512,8000);
5b.
colormap(hot);
5c.
t = [0:1/8000:1-1/8000];
y = sin(2*pi*800*(t.*t));
z = y(8000:-1:1);
specgram(z,512,8000);

6a.
y = auread('bark.au');
soundsc(y)
subplot(2,1,1); specgram(y,1024,8000,[],900)
subplot(2,1,2); plot(y)
6b.
y = auread('gong.au');
soundsc(y)
subplot(2,1,1); specgram(y,1024,8000,[],900)
subplot(2,1,2); plot(y)