Un progetto di laboratorio storico-didattico sull'origine dei numeri complessi

In this paper, a selection of passages from Piero della Francesca's Trattato d'abaco (c.1480), Girolamo Cardano's Ars magna (1545) and Rafael Bombelli's Algebra (1572) dedicated to solving second- and third-degree equations, with particular attention to the so-called "irreducible case," where square roots of negative numbers are provided. Critical analysis of the texts presented allows us to understand how the problem of manipulating such square roots was tackled by the two major Italian algebraists of the 16th century and to determine whether they can really be said to have discovered imaginary numbers and complex numbers.