XYPLOT may be used to generate simple functions such as

- Upon starting XYPLOT, the current directory will be displayed and
you will be prompted to enter a data file name. Simply press
**Enter**to create your own template dataset. If a data file has already been loaded, click on the*Math*menu and select*Template*. - Enter
*x1, x2,*and*dx*to specify the lower limit, upper limit, and step size for the set of points, e.g.`-10, 10, 0.5`

Data for the function

- Click on the
*Math*menu and select*Template*. - Enter values for
*x1, x2,*and*dx*:`-6.28,6.28,0.1` - Click on the
*Plot*menu, then the*Symbol*menu, and select*Line*to switch from a point plot to a line plot. - Click on the
*Math*menu and select*Rescale*. - At the prompt, enter the expression
`sin(y)`.

- Generate
*y = x*over the interval (-20, 20), with a step size of 0.1. - Generate
*y = sin(x)*over the same interval (-20, 20) and with the same step size. The*Plot List*at the top of the screen will show the*active plot*to be plot 2 and the*operand plot*to be plot 1. - Click on the
*Math*menu, then the*Arithmetic*menu, and select*Divide*. The dataset for plot 2 will be divided by the dataset for plot 1 to create a new dataset, which will be displayed as plot 3. This is the sinc function. - In order to see the sinc function better, you may remove
plots 1 and 2 from the plot display. First select the plot
to be removed by pressing the number key of that plot to
make it the active plot, then click on the
*Plot*menu and select*Drop*to drop the plot from the display.

- Generate the function
*y = x*over the interval (-2, 2) with a step size of 0.01 (see Example 1.1). - Click on the
*Math*menu and select*Rescale*. At the prompt, enter the expression`pol(y,1,1,0,0,0,1)`. The numbers in the expression represent the*polynomial coefficients*starting with the 0^{th}order coefficient.