Sea levels follow a periodic pattern of rise and fall called the tides. The graph below shows the sea
level at a certain beach, in feet, over two days, where time t is measured in hours after 12:00 a.m.
(midnight) on the first day.
Sea level (in feet)
48
(6.5, 46)
(18.5, 46)
44
40
36
32
28
24
20
16
12
8
4
(0.5, 0)
A
(12.5, 0).
2 4
6
8
10
12
14
16
18
20
22
24
Time (in hours)
Write an equation in terms of y, the sea level in feet, and t, time in
hours, to represent the given context.