Different representations of functions in a dynamic geometry environment Gunnar Gjone, dr. philos

This presentation relates to a research project at Rutgers University, New Jersey. In an after school program, 13 year-old students were introduced to adding and subtracting integers for identifying rules to match tables for linear and quadratic functions. They worked on their tables to recognize certain properties for linear functions. This work was inspired by the work of Robert B. Davis. The students were given paper and pencil for plotting/drawing and doing calculations. In addition they were using the dynamic geometry software for Casio Classpad 300 calculator. They worked mainly with the PC emulator for the calculator, called ClassPad Manager. The students used the program for plotting points in a coordinate system and for getting the graph and equation of the plotted graph, attending, in particular to properties such as slope, x and y-intercepts, and the domain and range of the functions. In this presentation, the focus is on the development of the students ’ understanding of linear functions with particular attention to how they made use of certain features of the tool to build and deepen their understanding. The paper will in particular focus on the work of one of the students who presented some convincing arguments about the functions discussed. We will also focus on the possibilities of the tool to promote understanding of the function concept