5.1.1 Identifying Linear Functions (continued) Example 4 Consumer Economics Application
For linear functions whose graphs are not horizontal, the domain and range are all real numbers. However, in many real-world situations, the domain and range must be restricted. For example, some quantities cannot be negative, such as time. The domain and range of a function can be restricted even further to a set of points. For example, a quantity such as a number of people can only be whole numbers. In this case, the function’s graph is discrete (the points are not connected) because every point on the line is not a solution of the function. However, sometimes these graphs will show a line through the points to indicate that the linear pattern, or trend, continues.
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