A scientist is studying the motion of waves by measuring the distance between the crests and troughs of waves in a particular area. He set up a series of buoys at equal intervals, and attached a depth detector to each buoy.
After gathering data, the scientist modeled the positions of the buoys at a specific instance with the given function, where x is the horizontal
distance, in feet, from the first buoy and f(x) is the depth of the water, in feet, at that location.
F(x) = 2cos(x/8x) +13

Select the correct representation of the buoy positions modeled by function