Travelling Waves and Beats

The first cell animates a travelling wave with arbitrary wave number, angular frequency and phase shift.

y = Cos[(k x)-(w t)+d];

k = 1;   w = 1;   d=0;

Do[Plot[y,{x,0,2Pi}],{t,0,2Pi,2Pi/10}];

The second cell plays a wave of arbitrary frequency.

z[t_] := Cos[w t];

w = 2Pi*440;

Play[z[t], {t,0,1}];

This cell animates the superposition of two waves of arbitrary angular frequency.

y = 2Cos[(a-b)(x-t)/2]Sin[(a+b)(x-t)/2];

a=8;   b=7;

Do[Plot[y,{x,0,2Pi}],{t,0,2Pi,2Pi/10}];

The last cell plays the superposition of two waves of arbitrary frequencies.

z[t_] := 2Cos[(a-b)t/2]Sin[(a+b)t/2];

a=2Pi*440;	b=2Pi*444;

Play[z[t], {t,0,1}];