Graphs that repeat and sort of look like a heartbeat
Problems 5.1–5.5 refer to the graph of periodic function f(x) below.
5.1 Identify the domain of f(x).
The domain of a function is the collection of values for which the function is defined. Given a graph of a function, the most straightforward method to determine its domain is to imagine a series of vertical lines on the coordinate plane. Any vertical line drawn on the plane that intersects the graph represents an x-value for which the function is defined (and, therefore, a value in the domain of the function).
The collection of all the numbers you can plug into the function, ...