Chapter 8.5, Problem 84E

(a)

To determine

To graph: The equation $r^2=40,000\cos \left(2\theta \right)$ for $0°\le \theta \le 360°$ and then by using the graph describe where the signal can be received and where cannot be received.

(b)

To determine

To graph: The equation $r^2=22,500\sin \left(2\theta \right)$ for $0°\le \theta \le 360°$ and then to interpret the result.