Texas Instruments TI-89 Titanium User Manual page 389

Drawing a Contour for the Z Value of a Selected Point Interactively
If a contour graph is currently displayed, you can specify a point on the graph and draw a
contour for the corresponding z value.
1. To display the
2 ˆ
2. Select
7:Draw Contour
3. Either:
Type the point's x value and press ¸, and then type the y value and press
•
¸.
– or –
• Move the cursor to the applicable point. (The cursor moves along the grid lines.)
Then press ¸.
For example, suppose the current graph is z1(x,y)=x
y=3, a contour is drawn for z=3.5.
Any existing contours remain on the graph. To remove the default contours, display
Note:
the Window editor (8 $) and set
3D Graphing
menu, press:
Draw
.
2 2
+.5y
.
ncontour=0
–5. If you specify x=2 and
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