Números complexos: um estudo acerca dos conhecimentos prévios e das noções de aplicabilidade na perspectiva dos alunos do 3º ano do ensino médio

Abstract

The general objective of this research was to study how students of last grade of high school have understood the Complex Numbers before and after the formalization of the concepts related to the topic. More precisely, it proposes a way to conduct some classes so that students have greater interest in the topic and there are also some suggestions that may help the process of teaching and learning the content. Thus, we tried to identify how students understand the Complex Numbers before the formalization of the concepts related to this topic. It was also taken into consideration how the students learn the already formalized concepts of the Complex Numbers by researching and identifying motivations and discouragement experienced during this process. The research was based on the presentation of the history related to the consolidation of the set of complex numbers, the formalization of the concepts related to this subject in the national curriculum guidelines and in the thematic of motivation. The corpus of this research is composed by fifty-three students from Escola Preparatória de Cadetes do Ar (EPCAR) To give subsidy to the research, the following strategy of work was adopted: a questionnaire was applied early in the process; after, classes which formalized the concepts enhanced with the historical aspects occurred. Then, there was a voluntary presentation about the applicability of Complex Numbers performed by students; after all the content has been covered, an interdisciplinary practice with Physics promoted the contextualization, and, to sum up, the students answered a second questionnaire which allowed for identifying motivations and discouragement experienced in this process. During the research, we were helped by the observations written down in a field diary. For data analysis, responses to the questionnaires were considered. Some of those given through graphs that relativized students responses; others were grouped by similarity. The sequence of accounts of the students concerning their presentations was listed. It was concluded that such benefit was a change in the way of thinking of those students, promoting an improvement in the process of teaching and learning. This practice resulting from teacher motivation which seeks alternative teaching applies to any discipline.