Chapter 22: Inverse Trigonometric Functions: Situation 16 From the MACMTL-CPTM Situations Project

Three prospective teachers planned a unit of trigonometry as part of their work in a methods course on the teaching and learning of secondary mathematics. They developed a plan in which high school students would ?rst encounter what the prospective teachers called the three basic trig functions : sine, cosine, and tangent. The prospective teachers indicated in their plan that students next would work with “the inverse functions,” which they identified as secant, cosecant, and cotangent.

The Foci draw on the general concept of inverse and its multiple uses in school mathematics. Key ideas related to the inverse are the operation involved, the set of elements on which the operation is defined, and the identity element given this operation and set of elements. The crux of the issue raised by the Prompt lies in the use of the term inverse with both functions and operations.