This is essentially a vast generalization of my previous question: Examples of separable ordinary differential equations in economics
I'm giving a talk to college-level math teachers on some applications of mathematics to Economics. My main goal is to try to convince them is that it's possible to integrate examples and methods from economics that are both elegant and lead to real economic insight into Calculus and Linear Algebra courses. I'm probably going to skip the Leontief input-output model, as well as very basic game theory and present- and future-value calculations, since I think those are all pretty standard. I want to keep the scope of the talk manageable, so I'm going to steer clear of any statistical methods.
I'm definitely going to talk about the Keynesian multiplier, the interpretation of Lagrange multipliers as shadow prices, and about how one can use implicit differentiation to determine the incidence of taxes on supplier and consumer.
My question is the following: does anyone have any suggestions for other topics?