Chapter 8 - Polar Coordinates; Vectors - Section 8.2 Polar Equations and Graphs - 8.2 Assess Your Understanding - Page 606: 20

$ y=-2$ a horizontal line 2 units below the polar axis. See graph.

1. Use the formula $r\ sin\theta=y$, we have $r\ sin\theta=-2\rightarrow y=-2$ 2. We can identify the above equation as a horizontal line 2 units below the polar axis. 3. See graph.