This work is situated in the context of the secondary-tertiary transition in analysis. From the results of a test in the first year of university, we find low success rates in the calculation of limits of functions, which do not increase considerably when the graph of the function is given. To understand the lack of success in these tasks, we interview students and analyse the mathematical activities they develop (or not) when answering the test. For this, we use Activity Theory in Didactics of Mathematics, focusing on the notion of semiotic control as well as that of deconstructions with localisation perspectives.