Learning complex functions with GeoGebra

In this paper we describe a teaching experiment targeting with students of Complex Analysis attending an undergraduate course of a portuguese university. Our main goal is the understanding of the GeoGebra role with respected to visualization and as technological mediator, according to Vygotsky theory, in the teaching and learning process of complex functions. The first step of our study was the conception of a sequence of didactical tasks and the development of GeoGebra tools related to the target didactical objectives. Here we will describe the procedure related to the tasks implementation in a classroom environment and the achieved results based on the collected data composed by written assignements produced by students, video recording the student performance during the experiment and the student constructions with GeoGebra. All the collected data was analysed from a qualitative and interpretative paradigm.