Sharing Teaching Ideas
Sharing Teaching Ideas: Understanding Functions without Using the Vertical Line Test
September 2005, Volume 99, Issue 2, Page 96
The author's attempt to replace vertical line testing of relations with more genuine student reasoning about the function definition and its defining criteria. Instead, the author adheres to the definition of function and employs mapping between the domain and the range. The author's thinking, lesson examples and examples of student work are discussed.