Abstract
Tanaka, (2005) pointed out two roles of Dynamic Geometry Environment (DGE); one makes students to be able to conjecture with gathering data inductively, and another gives a perspective for deductive inferring to make the conjecture universal. In this research, we consider that the teaching and learning processes are based on the above roles. Hence, our target is to consider students' expected activities and teacher's supports. The purpose of this paper makes clear them. A didactical experiment is analyzed, which focuses on the first role of DGE. We analyze both student's activities and teacher's support through this experiment. In conclusion, we propose three cases for student's activities and teacher's support corresponding to above analyses. ・Case1: When students conjecture inductively, but it is not to coincide with teacher's intention, it is not a path to solve the problem directly; a teacher suggests modifying students' inductive activities. ・Case2: Students make a conjecture without conviction by using functions of Dynamic Geometry software; a teacher suggests for students to make sense of their conjecture. ・Case3: Students are not specifying the method of inductively gathering facts; a teacher suggests for them to describe the procedure how to gather data.
