The tidal variation in Desolation Sound on the west coast of Canada is roughly 4 meters. That is, the difference beween water depth at high tide and at low tide is 4 meters, with successive high tides occurring 12.5 hours apart. Suppose that at Refuge Cove in Desolation Sound, the depth of water in meters is given by D(t) = D0 + Acos B(t - t0)