Relações trigonométricas fundamentais

Abstract

The present research aims to present classic demonstrations of the fundamental relations of Trigonometry,with a simple approach, and exploring flat shapes. The intention is to make such demonstrations better known and provide a highlight for Trigonometry, since they are essential in solving problems of everyday life. For this purpose, we made a historical highlighting of the importance of trigonometry in the mathematical context. Since we know Trigonometry is loosing its status and not being considered essential in basic education anymore, such demonstrations, associated with the flat shapes, may be used as a model class. Therefore, we highlight the following fundamental relations: Basic Trigonometric relations, Derived Relations, Sine of the Sum and Difference of Two Arcs, Cosine of the Sum and Difference of Two Arcs, Double Arcs, Half Arc, Transformation in Product and Applications. For the demonstration ot these relations we used some area results, cosine law, Ptolemy’s theorem and the theorem of the broken chord Plane Geometry. We believe that Trigonometry is linked to the formation of these flat shapes. Thus, such demonstrationas associated to these flat shapes may serve to improve the Trigonometry teaching- learning and as motivator for students and teachers seeking to enhance their knowledge in mathematics.