Derive an equation d = acos(bt) for the displacement d (in feet) in relation to sea level of a piece of cloth tied to a water wheel over t seconds. Assume the water wheel is half-submerged and takes 24 seconds to complete one turn. At t = 0 seconds, the cloth is at a height of 10 feet above sea level, its maximum displacement from the surface of the water.

Find the values of a and b.