Texas Instruments TI-83 PLUS - Manual (Page 143)

TI-83 Plus Function Graphing 140
To use ZBox to define another box within the new graph, repeat steps 2
through 4. To cancel ZBox , press ‘ .
Zoom In, Zoom Out
Zoom In magnifies the part of the graph that surrounds the cursor
location. Zoom Out displays a greater portion of the graph, centered on
the cursor location. The XFact and YFact settings determine the extent of
the zoom.
To zoom in on a graph, follow these steps.
1. Check XFact and YFact ; change as needed.
2. Select 2:Zoom In from the
ZOOM
menu. The zoom cursor is displayed.
3. Move the zoom cursor to the point that is to be the center of the new
viewing window.