Abstract
In this paper, we aim to investigate undergraduate students’ second-order covariational reasoning. For this purpose, we designed a teaching sequence concerning the characterization of paraboloids and involving the use of two combined digital tools, GeoGebra AR and GeoGebra 3D, to help students develop covariational reasoning. The teaching sequence was experimented with 30 undergraduate students in mathematics. The research data were collected over two collective discussions and consisted of audio and video recordings. The data analysis was based on a descriptive coding of the emerging forms of covariational reasoning. Findings revealed that the adopted digital tools supported students’ covariational reasoning when conceptualizing paraboloids.