Beats will plot two sinusoids and their sum.
Graph Database file beats.85d for the TI-85.


Beats will plot two sinusoids and their sum.  Initially,
only the sum is selected.  The mathematics involved is
relevant to the hearing of "beats" when two sources of
sound are played together.  The "beat frequency" is the
difference between the two separate frequencies.  y4 is
analytically correct if A1 = A2.  It is a good approximation
when A1 in nearly A2.
On the home screen set values of A1, A2, f1 and f2:
1 -> A1
1 -> A2
10 -> f1
11 -> f2