A Synergy between History of Mathematics and Mathematics Education: A Possible Path from Geometry to Symbolic Algebra

This paper proposes an experimental path aimed at guiding upper secondary school students to overcome that discontinuity, often perceived by them, between learning geometry and learning algebra. This path contributes to making students aware of how the algebraic language, formalized in the most powerful form by Descartes, grafts itself onto the geometric language. This is realized by introducing a problem included in a text written by Abu Kamil before the year 870. This awareness acquired by the students, when accompanied by some semiotic considerations, allows the translation of the problem from "spoken" algebra to "symbolic" algebra, and it represents the background for a possible use of the same problem within the framework of analytic geometry. This proposition manifests a didactic and popular efficacy that supports and favors the recognition of the object it is talking about in different contexts, helping to create a unitary vision of mathematics.