Similarity Between Conics and Cubic Curves: Curious and Novel Results Explained in High School Language
Similarity; conics; polynomials of 3-degree
In this dissertation, we investigate the notion of similarity between curves, understood as a natural generalization of the concept of similarity between triangles. Based on this definition, we analyze criteria for determining when parabolas, ellipses, and hyperbolas are similar. We then propose a didactic activity aimed at providing teachers with a pedagogical approach that allows high school students to understand that any two parabolas are similar. Finally, we present a theorem that guarantees that the graph of any cubic polynomial can be obtained from the graph of the function $y = x^3$ through similarity functions and a shear transformation. As a consequence of this result, we establish a criterion that makes it possible to verify when the graph of a degree-3 polynomial is similar to the graph of $y = x^3$.