Chapter 6 - Inverse Circular Functions and Trigonometric Equations - Section 6.3 Trigonometric Equations II - 6.3 Exercises - Page 274: 48b

We can see a sketch of the graph of this function over the interval $[0.15, 1.15]$ We can see that there are 4 beats in one second.

Consider the frequencies $220~Hz$ and $216~Hz$ $P_1 = 0.005~sin~440~\pi~t$ $P_2 = 0.005~sin~432~\pi~t$ $P= P_1+P_2 = 0.005~sin~440~\pi~t+ 0.005~sin~432~\pi~t$ We can see a sketch of the graph of this function over the interval $[0.15, 1.15]$ We can see that there are 4 beats in one second.