05. GraphGrid – The trigonometry tool

Sine, cosine and tangent – Basic functions with the trigonometry tool

The trigonometry tool supplied with the GraphGrid is used to draw basic trigonometric functions. The tool includes two curves: a half period of a sine wave and (almost) a quarter period of a tangent. The scale of both curves is the same. A distance of 4 centimeters along the X-axis corresponds with 90 degrees. When the sine and the tangent functions have a value of 1, the distance along the Y-axis in the drawing is 4 centimeters. These dimensions provide sufficient ‘tactile space’.
Because the templates for the sine and tangent are only a part of a whole period of these functions, it is necessary to draw these segments multiple times in order to draw one or more whole periods of the graph.

The trigonometry tool has small indents and hooks as pen-stops. If you run along or against these pen-stops with the tip of your pen, you know the exact position on the tool. Along the straight sides of the tool, pen-stops are provided every centimeter. On the curves of the sine and tangent, the pen-stops indicate the ​​30, 45, 60 and 90 degree positions.
At both ends of the two curves you will find small hooks as pen-stops. These can be used to flip the tool around a pin or the tip of the pen to draw the next part of the graph without interrupted lines. Using the small, well-marked holes in three of its corners, the trigonometry tool can be fixated on the rubber layer of the TactiPad with small pins.