
In this paper the effectiveness of the introduction of imaginary numbers by an historical example is examined by a test (High School, pupils aged 16-18 years). We verified if the presence of imaginary numbers in a passage (according to a resolution by Bombelli, from Algebra, 1572) of a cubic equation and in the result of a quadratic equation is accepted or refused by pupils. We conclude that, in the sphere of Mathematics Education, effects of teacher's choices must be experimentally verified: the presence of this experimental sphere reinforces the use of history of mathematics, changes the outlining of the educational research and gives it a particular epistemological status.