SOLUTION: Use a cosine function to describe the height of the tides of the ocean if high tide raises the water level to 5 m at noon and low tide drops it down to 1 m at 4 p.m. Let t = 0 be 1

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Question 1205129: Use a cosine function to describe the height of the tides of the ocean if high tide raises the water level to 5 m at noon and low tide drops it down to 1 m at 4 p.m. Let t = 0 be 12 noon.
Answer by ikleyn(52884) About Me  (Show Source):
You can put this solution on YOUR website!
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Use a cosine function to describe the height of the tides of the ocean if high tide raises
the water level to 5 m at noon and low tide drops it down to 1 m at 4 p.m. Let t = 0 be 12 noon.
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Mid-line is half the sum of the maximum and the minimum height  %285%2B1%29%2F2 = 6%2F2 = 3 meters.

The amplitude is half the difference of the maximum and the minimum height  %285-1%29%2F2 = 4%2F2 = 2 meters.

Since the cosine function has the maximum at 12 noon, which corresponds to t= 0, it means
that the shift of the cosine function is zero.


The half of the period of the cosine function is 4 hours from 12 noon (maximum height) 
to 4 p.m. (minimum height) - so, the period is 8 hours.


Now we have everything to write the cosine function for the water level

    h(t) = 2%2Acos%282%2Api%2At%2F8%29 + 3  meters.

Solved.