Answer:
See attached for a graph
Step-by-step explanation:
We're going to plot sea level as y=0 and a depth of 8 meters as y=-8.
The problem statement tells you the initial point (x=0) is at normal ocean depth (y=-8), so the first point you put into your sine tool is ...
(x, y) = (0, -8)
The buoy takes 16 seconds to go from a high point to a low point, so the time to the first high point is half that, or x=8 seconds. That high point is 5 meters above its average depth, so is at y=-3.
The second point you will put into your sine tool is ...
(x, y) = (8, -3)
