Answer:
Since the question doesn't mention in what tide the answer should be, I will be giving a solution to both, the high and low tide. Hope this helps :)
Step-by-step explanation:
Using a cosine function, where time is measured in hours past high
tide: y=4cos30x + 10
Using a cosine function, where time is measured in hours past low
tide: y = 4cos[30(x-6)]+10
