This three-part example illustrates the use of iteration, recursion, and algebra to model and analyze the changing amount of medicine in an athlete's body.

In Modeling the Situation, an interactive environment is used to become familiar with the parameters involved and the range of results that can be obtained. In the second part, Long-Term Effect, the interactive environment is used to investigate how changing parameter values affects the stabilization level of medicine in the body. In the third part, Graphing the Situation, an interactive graphical analysis provides a visual interpretation of the results. Through multiple representations of a common concept, better insight into, and a deeper understanding of, the problem situation can be achieved.