Water Level in Cape May, NJ

Topic:
Functions
The plot below shows the water level in Cape May, NJ beginning at 9:00 a.m. on October 13, 2009. Try to find equations of the form f(x) = a*cos(b(x-c)) + d and f(x) = a*sin(b(x-c) +d. You can use the sliders to help you locate important points on the curve in order to find appropriate values for a, b, c, and d.