Explore the graph of the function

for values of **x** between **-2** and **2** to view geometrically
that the graph of this function is symmetric with respect to the **y**-axis.

In the following LiveMath Notebook, you can view the graph of

Note that as you change the value of **a**, the points **(a, f(a))** and **(-a, f(-a))** still appear to be symmetric with respect to the
**y**-axis.

You can change the function in the notebook above. Try

- x
^{4}- 9x^{2}

[You will need to zoom out to see the entire line segment. To zoom out, click on the 'rocket ship' on the upper left-hand corner of the graph.] - x
^{6}- 9x^{2} - x
^{4}- 9x^{3} - x
^{6}- 9x^{4}