A UNIDADE IMAGINÁRIA: AS IMAGENS CONCEITUAIS EVOCADAS POR ALUNOS DE UM CURSO DE LICENCIATURA EM CIÊNCIAS / IMAGINARY UNIT: THE CONCEPT IMAGE EVOKED BY STUDENTS OF A BACHELOR'S DEGREE IN SCIENCE

Complex numbers represent a theoretical issue and are usually presented in a formal approach wrapped in an algebraic framework, which makes a difficulty understanding for high school and college students. The aim of this article was to find out how the conceptual image of complex numbers is expressed by students of a Bachelor's Degree in Science in relation to the imaginary unit and to see if and to what extent this conceptual image can be increased through a didactic intervention. The imaginary unity is an obstacle to complex numbers learning, which requires a survey of the evoked concept image by students in facing to activities involving complex numbers. In the methodological part, a didactic intervention was developed and applied, adapted from the three initial phases of the Dialectic Tool-Object, described in Douady (1986), to students of a public university at São Paulo state. The results revealed a little improvement in the students' conceptual image promoted by the possibility of changing from the arithmetic to the geometric frame arising from the didactic intervention application.