A essência dos determinantes na sua origem

Abstract

The goal of this work is to present the concept of determinants in high-school level in order to show its origins and to formulate some demonstrations which are omitted in school books. The concept of second order determinants were developed using two equations and two variables linear systems, associating them to square matrices and exhibiting the common denominator which results from the calculation of each variable. The same idea was applied to develop third order determinants, this time associating with a 3 equations in 3 variables linear system to, then, demonstrate the rule of Sarrus and compare it with the general definition for determinants introduced by Laplace. In the last chapter, it’s presented the definition of determinants using permutations in rows or columns in order to favor the demonstration of some important properties which simplify the calculation of determinants of order greater than 3. The chapter ends with the resolution of some complex questions whose calculation is much easier with the use of those properties.