standard_description: Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function A = s2 giving the area of a square as a function of its side length is not linear because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straight line.
problem_activity: Task
The figure below gives the depth of the water at Montauk
Point, New York, for a day in November.
[IMG]
How many high tides took place on this day?
How many low tides took place on this day?
How much time elapsed in between high tides?


aligns: no