Question

Tides go up and down in a 12.4-hour period. The depth of a certain river ranges from 9 to
21 m. The variation can be approximated by a sine curve.
a. Write an equation that gives the approximate variation y, if x is the number of
hours after midnight if high tide occurs at 5:00 am.
b. Determine the depth of the river at 2:44 pm.
c. Determine all times in a 24-hour time period when the depth of the river is exactly
12 feet.