Abstract:

Usually, the graph of trigonometric function is treated one of the most difficult graphs to sketch, and considered to be an end outcome by algebraic calculations. Since many textbooks use the algebraic approach only for sketching the graph, which gives students a restricted way of looking at the problem, students do not have a chance to develop their ability to solve the problem graphically. This paper explores if it would be possible to derive the result, including sketches of the graph of trigonometric functions, from graphical approach which rely on graph transformations of the unit box of the basic trigonometric functions. This article also includes a study conducted on a group of high school teachers, which shows that many of them are not accustomed to this type (graphically) of approach and have trouble to solve the problem even algebraically. The study shows that the graphical approach gives better chance to get the result with less algebraic calculations.

Keywords:

Trigonometric function, unit box, graph transformation, basic function.