GeoGebra applets and homework tasks to help engineering students with 3D visualization in a multivariable calculus course

In this article, we will examine, for 82 first-year Management Engineering students at Udine University, the difficulties of graphically representing regions in space, surface boundaries of these regions, and curve boundaries of these surfaces, and suggest GeoGebra Applets to overcome them. This included the design, and the analysis of the strategy used, and difficulties encountered in three unfamiliar tasks given as homework, two at the beginning and one during the course, and a non-anonymous Moodle questionnaire. The homework tasks were followed by the design and the use in class of ad-hoc GeoGebra Applets, left available to the students for personal use. The activities will be presented by specifying the aspects indicated in the DiGIMATH good practice guidelines. The potential and limitations of GeoGebra for these subjects will also be illustrated. Since the proposed object of study has not been studied a lot, our research is qualitative and exploratory, based on Duval’s theory of registers of semiotic representation and the Visual-analytical model. Thematic analysis will be used to analyse the responses to the questionnaire.