Cost functions essentially break down how a cost reacts over time to changes to the activity that drives it. Variations in the cost drivers explain the variations in cost functions over time. Cost behaviors represent the differences in how these cost functions react over time to the changes of the cost drivers.

Describe an example of a specific cost function, and its associated cost driver. In your description, discuss how changes in the cost driver will impact that cost function and what types of cost behaviors you would expect and why.