Today, high tide measured 7.5 ft and low tide measured 3 ft. What is the amplitude of a cosine function modeling the depth of the water in feet as a function of time in hours?

Answer 1

Since the tide varies from 3.00- 7.5 the midline is the average which is (7 +3.5)/2 = 10.5/2 = 5.25

The amplitude is the absolute distance from the midline to the peak or trough which is 7- 5.25 = 1.75