Abstract
We present a genetic decomposition of the concept of tangent line view as a hypothetical learning trajectory. To generate this genetic decomposition we performed a historical analysis of the genesis of the concept, analyzed different high school mathematics textbooks, conducted a synthesis of the
findings of research on understanding the tangent line, and designed a questionnaire that was
completed by high school students in a pilot study. The genetic decomposition generated considers the analytical and geometrical perspectives as a means to promote the thematization of the schema of tangent line.
