Texas Instruments PLUS TI-89 - Manual (Page 162)

Chapter 9: Sequence Graphing 145
09SEQUEN.DOC TI-89/TI-92 Plus: Sequence Graphing (English) Susan Gullord Revised: 02/23/01 10:59 AM Printed: 02/23/01 2:14 PM Page 145 of 14
As in function graphing, you can explore a graph by using the
following tools. Any displayed coordinates are shown in rectangular
or polar form as set in the graph format.
Tool For Sequence Graphs:
Free-Moving
Cursor Works just as it does for function graphs.
„ Zoom Works just as it does for function graphs.
¦ Only x ( xmin , xmax , xscl ) and y ( ymin , ymax , yscl )
Window variables are affected.
¦ The n and plot Window variables ( nmin , nmax ,
plotStrt , plotStep ) are not affected unless you select
6:ZoomStd (which sets all Window variables to
their standard values).
… Trace Depending on whether you use TIME , CUSTOM , or
WEB axes, Trace operates very differently.
¦ With TIME or CUSTOM axes, you move the cursor
along the sequence one plotstep at a time. To move
approximately ten plotted points at a time, press
2 B or 2 A.
−
When you begin a trace, the cursor is on the
first selected sequence at the term number
specified by
plotstrt , even if it is outside the
viewing window.
−
QuickCenter applies to all directions. If you
move the cursor off the screen (top or bottom,
left or right), press ¸ to center the viewing
window on the cursor location.
¦ With WEB axes, the trace cursor follows the web,
not the sequence. Refer to page 147.
‡ Math Only 1:Value is available for sequence graphs.
¦ With TIME and WEB axes, the u(n) value
(represented by yc ) is displayed for a specified
n value.
¦ With CUSTOM axes, the values that correspond to
x and y depend on the axes you choose.
Exploring a Graph
Tip: During a trace, you can
evaluate a sequence by
typing a value for n and
pressing
¸ .
Tip: You can use
QuickCenter at any time
during a trace, even if the
cursor is still on the screen.