Idempotent

Teachers frequently get questions from students who are very astute or just curious. A math question that seems simple may have a difficult answer or the answer may connect in unexpected ways to other ideas. This text aims to address commonly asked questions about the algebra curriculum that require expert knowledge to answer. Questions addressed: I don't understand the "machine" analogy for functions.Why does a function have to pass the vertical line test?How is a sequence different from a

Geometric mean is a topic in geometry that is only used to calculate a pointless length in right triangles. It is a throwaway topic, right? If your students are tired of having their time wasted memorizing calculations they will never use again, they will be demanding to know why they should learn about the geometric mean. Included are three mini-lessons -- one each for geometry honors, precalculus honors, BC calculus. You are saying, "But I only teach, geometry. Why would I bother paying f