Student evaluation of mathematical statements using dynamic geometry software

Abstract

The research question addressed by this study is whether or not students made effective use of dynamic geometry software to explore the validity of a geometrical statement. Particular attention was paid to the use of definitions and the types of justifications students employed. Interviews conducted with six secondary mathematics preservice teachers were video and audio taped and video output of the interviewee's Geometer's Sketchpad (GSP) work was recorded on video tape. The interviews were transcribed along with a synchronized record of the GSP work. The transcripts and videotapes were analysed and coded. Results indicated that reasoning based on prototypically constructed categories and difficulty correctly parsing mathematical statements, especially the ‘for all’ quantifier, interfered with the effective use of dynamic geometry software in justifying mathematical assertions. It may be that explicit instruction in how to make use of software programs to explore the validity of an assertion is needed.