HP 39gs Graphing manual Build Your Own menu keys, Example plotting a circle

“Build Your Own” menu keys

Key		Meaning
		Puts the highlighted independent
		value (X, T, θ, or N) into the edit
		line. Pressing			replaces
					current value.
		this variable with its
		Inserts a zero value at the position
		of the highlight. Replace a zero
		by typing the number you want
		and pressing	.
		Sorts the independent variable
		values into ascending or
		descending order. Press
		and select the ascending or
		descending option from the
		menu, and press		.
		Toggles between two character
		sizes.
		Displays the defining function
		expression for the highlighted
		column.
		Deletes the highlighted row.
	CLEAR	Clears all data from the table.

Example: plotting a circle

Plot the circle, x 2+ y 2 = 9. First rearrange it to read

y= ± 9 – x2 .

To plot both the positive and negative y values, you need to define two equations as follows:

y = 9 – x2 and y = – 9 – x2

2-20 Aplets and their views