Researchers point out that more educational research is needed to study students’ understanding of trigonometric topics. The present research attempts to study a group of three high-achieving eleventh grade students’ realization of trigonometric words and narratives associated with the sine function. The learning of the students was video recorded and analyzed using the commognitive theoretical framework. The research results indicated that the students performed inductive and deductive processes, with the mediation of technology, to realize new trigonometric significations; the unit circle and the coordinate system, including words and narratives associated with these significations. Technology functioned as static and dynamic visual mediators. It functioned as a static visual mediator when it mediated the deductive processes of the students, while it functioned as a dynamic visual mediator when it mediated the inductive processes of the students. The students’ processes, technology and the teacher’s processes combined to mediate the students’ sameness, encapsulation and reification of trigonometric words and narratives. The research results indicate the important role of the different trigonometric significations for students’ understanding of trigonometric functions. These significations were mediated by technological tools.
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