A trigonometria do ciclo trigonométrico : uma análise da transposição didática realizada pelo livro didático na 2ª série do ensino médio à luz da teoria antropológica do didático.

Abstract

Trigonometry is a concept of mathematics used in several fields of knowledge. For this reason, the teaching of this scholarship in basic education seems to be essential. The lack of research on teaching this concept, among other things, motivated us to conduct this research. The goal of this quest is to analyze the Didactic Transposition of Trigonometry, specifically the first round of the trigonometric cycle, through the activities presented in the textbook of the second year of high school. In support of our research, we chose the studies of Chevallard, and other authors, on the external didactic transposition as our focus, particularly the ones related to the transformations suffered by knowledge, from production to the way they appear in textbooks. Three works have been used, one in the main analysis, and the others in further analysis, especially in the construction of a priori modeling. In addition to the textbooks, we analyzed the official documents that guide the Brazilian education, aiming to check how trigonometry is treated in those documents. To analyze the data of our research, we use the framework of Anthropological Theory of the Didactic - ATD. We identified the tasks (types and subtypes), the techniques, technologies and theories addressed in the proposed activities. The results of our analysis show that the textbooks have different ways of approaching knowledge, as a result of the transformation of didactic transposition suffered by this knowledge. We noticed that, sometimes, there was suppression of some aspects related to Trigonometry while, in other moments, it was clear a more emphatic approach of less relevant aspects, according to the official documents, prioritizing certain types of tasks over others. The results of this research led us to reflect on the importance of mathematics praxeology in the teaching and learning process.