The depth of the water at a marker 20 feet from the shore in a bay is depicted in the graph below 1 2 3 d 201 4 M 10 If the depth d is measured in feet and time t is measured in hours since midnight what is an equation for the depth of the water at the marker d 5 cos 7 1 6 d 9cos d 9sin 6 T d 5 sin in 7 6 T 6 t 9 5 5 12 t 9 18 t