A mathematical model is an equation or system of equations and/or inequalities used to describe data from real world situations and to make predictions from that data. The model may be as simple as a linear function or as complicated as a system of hundreds or even thousands of higher degree equations programmed into a powerful computer. Whatever the complexity of the model, the goal of the modeler is to create a mathematical system which comes as close as possible to capturing both the quantitative and qualitative properties of the real world system being modeled. Thus if an economist collects data on price and demand and observes that her data seems to be quite linear, she will undoubtedly attempt to find a linear function that is a good fit for the collected data. Her desire is to be able to make predictions about future demand based on...