Demonstration model for trigonometric functions - comprising plate with inscribed circle with pegs holding elastic ring forming triangle

摘要

The model for demonstrating trigonometric functions to schoolchildren consists of a plate with a demonstration field containing a circle or segment of a circle. Alongside the demonstration field is a separate field with angle values on the abscissa axis and angle function values on the ordinate axis. The corners of the plate have holes for rubber feet, so enabling the plate, when transparent, to be placed on an overhead projector plate. Tension pegs are arranged in the centre point of the circle segment, as well as points long in the horizontal line and along the circumference. A rubber band is placed around the centre peg and two others for demonstration purposes.