ring a 24-hour day, the tides raise and lower the depth of water at a pier as shown in the figure below. Write an equation of the form f(t) = A cos Bt + d that gives the depth of the water at time t. :) = d the depth of the water at 6 P.M. ft f(t)+ Depth, in feet 12 S 12 18 t is the number of hours from 6 A.M. 24 t