# Symmetrical Functions

Learning to understand and read tactile lines of graphs for fundamental symmetrical functions. Functions work wonders!

This material is suitable for middle school students and is specifically designed for those teaching or wanting to teach visually impaired children mathematics.

Practical work on constructing some symmetrical functions will involve not only plotting the graph on paper and the board but also molding this graph out of clay. Why use clay for practical work? To develop fine motor skills, to fixate gaze, and to enhance eye movement and muscle coordination.

Symmetrical functions are those that are symmetrical about the Y-axis or the origin. Let’s consider the absolute value function. This function is symmetrical about the Y-axis.

Representing the Absolute Value Function with Clay

Develop tactile perception and observance. The graph resembles a “V.” The branches of the graph are symmetrical about the Y-axis. If you need to plot the graph with a horizontal shift, it will also be symmetrical about the Y-axis.

Make two graphs from clay with movement along the Y-axis.

Observe that the branches of the graph are symmetrical about the Y-axis.

**Movement of the Graph along the X-axis**

Observe that in this case, there is no symmetry about the Y-axis.

**About the Color of the Clay**

Use bright colors for the work; yellow is most commonly used because it is the last color the eye stops distinguishing. Yellow is also visible in bad weather conditions.

**Graph of the Inverse Proportionality Function y = k/x. **This graph is symmetrical about the origin. Study the three-dimensional representation of the function’s graph. It is known that the fingertips have numerous reflex zones, massaging which improves the body’s condition and the functioning of the autonomic nervous system. Fingers – clay – graph.

Remember that for visually impaired students, tactile sensations are one of the channels of perception, which belong to tactile perception. It might be easier for students with visual impairments to understand the concept by not only drawing the graph in their notebooks but also feeling it, thus engaging contact sensations. This helps them to remember the information faster.