Análisis cognitivo de situaciones problema con sistemas de ecuaciones algebraicas en el contexto del balance de materia

in this article, a research that carries out the cognitive analysis of a focus group is reported, where students from a technical university career approach the systems of linear algebraic equations in the context of matter balance in problem situations of chemical mixtures. the cognitive analysis of the focus group is based on the theories of conceptual fields and on the mathematics in the sciences context. in order to do the analysis, special attention is placed in the representations built by students on the invariants in the understanding scheme and in the solution scheme, when facing a problem of contextualized mathematics. while analyzing students' acting, different types of own representations of the context arise during the development of the research, and consequently a proposal of classification for those types of representation settles down.