This is on the Algebra 2 unit (Graphs & Sinusoidal Functions) I'm having a hard time understanding this unit. can someone explain how to do these two problems please?

Q1: Suppose that the height H of a Ferris wheel can be modeled by the function H(t) = -12cos ( πt/45) + 18, where t is the time in seconds. What is the maximum height of a cabin? Use 3.14 for π.

Q2: The tide at an Eastern seaport is at its maximum at 6:39 a. m. High tide is 9 ft deep. Low tide occurs at 12:30 p. m. with a depth of 3 ft. The water depths can be modeled by a sinusoidal function.
Allow x = 0 represent midnight.
Find the following and make sure to show work for the midline and amplitude:

period=
Amplitude=
Maximum=
Equation of the midline:
minimum=