graph the three functions y = f(x), y = f(-x), and y = -f(-x) and see if any two of the graphs coincide.

1. Prepare the program for graphics.
2. If the first menu item is Algebra then press .
3. Press for Author.
4. Enter the function f(x) := sin(x) + 4x^3
5. Press twice to get the graph. Note the color of the graph.
6. Press twice and enter f(-x)
7. Press twice to get the graph. Again note the color of the graph.
8. Press twice and enter -f(-x)
9. Press twice to get the graph. Again note the color of the graph.

It appears from the drawing of the latter graph that the two functions y = f(x) and y = -f(-x) are the same. Hence, it appears that the function y = f(x) is odd.