• The Mathematical Education
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• v.52 no.3
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• pp.271-301
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• 2013

The purpose of the study was to investigate how students generalize and prove the factoring of $x^n-1$ using a Computer Algebra System application and the role of CAS in this process. The theoretical framework consists of the anthropological and the instrumental approach. In particular, the basis of the Task-Technique-Theorization(T-T-T) frame adapted form Chevallard's anthropological approach of Didactics is utilized. We found that Technique-Theorization emerges in mutual interaction between paper-and-pencil techniques and computer algebra techniques. And this interaction led to the students' theoretical reflection and conceptual understanding. In this process, we could identify three epistemic role of CAS : the role of checking the result, the role of cognitive stimulation and the role of extending thinking. Therefore CAS plays on a epistemic role of checking the result of a task, stimulating the student' cognition and extending their thinking as well as pragmatic role of producing the result of a input.