In the previous sections, you observed students using the Reasoning and Proof Standard. You explored your own relation to these concept in the Part B Interactive Activity on triangular and square numbers. In Part C, we developed working definitions of some of the related concepts and explored their value. Now that you are familiar with the Standard and some of its aspects, it's time to apply it in an actual classroom setting.
Harriette Davis is working with her eleventh-grade pre-calculus course to find functions that provide "boundaries" for trigonometric functions. In the class these are termed "enveloping" functions. They will use this information as they reason about and build understanding of symmetries, asymptotes, and, limits.
Before we view the students' work, please use this activity to review the underlying mathematics.
