Over a 24-hour period, the tide in a harbor can be modeled by one period of a sinusoidal function. The tide measures 5 ft at midnight, rises to a high of 9 ft, falls to a low of 1 ft, and then rises to 5 ft by the next midnight. What is the equation for the sine function f(x), where x represents time in hours since the beginning of the 24-hour period, that models the situation?

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