Selecting sequences, Selecting the display style, Window variables – Texas Instruments PLUS TI-89 User Manual

Page 160

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Chapter 9: Sequence Graphing 143

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 143 of 14

With

TIME

and

WEB

axes, the

TI

-89 / TI-92 Plus

graphs only the

selected sequences. If you entered any sequences that require an
initial value, you must enter the corresponding

ui

value.

With

CUSTOM

axes, when you specify a sequence in the custom

settings, it is graphed regardless of whether it is selected.

Only the

Line

,

Dot

,

Square

, and

Thick

styles are available for sequence

graphs.

Dot

and

Square

mark only those discrete integer values (in

plotstep

increments) at which a sequence is plotted.

The Window Editor maintains an independent set of Window
variables for each

Graph

mode setting (just as the Y= Editor

maintains independent function lists). Sequence graphs use the
following Window variables.

Variable

Description

nmin, nmax

Smallest and largest

n

values to evaluate. Sequences

are evaluated at:

u(nmin)
u(nmin+1)
u(nmin+2)
... not to exceed ...
u(nmax)

plotStrt

The term number that will be the first one plotted
(depending on

plotstep

). For example, to begin plotting

with the 2nd term in the sequence, set

plotstrt = 2

. The

first term will be evaluated at

nmin

but not plotted.

plotStep

Incremental

n

value for graphing only. This does not

affect how the sequence is evaluated, only which points
are plotted. For example, suppose

plotstep = 2

. The

sequence is evaluated at each consecutive integer but
is plotted at only every other integer.

xmin

,

xmax

,

ymin

,

ymax

Boundaries of the viewing window.

xscl

,

yscl

Distance between tick marks on the x and y axes.

Selecting
Sequences

Note: With TIME and
CUSTOM

axes, all defined

sequences are evaluated
even if they are not plotted.

Selecting the
Display Style

Window Variables

Note: Both nmin and nmax
must be positive integers,
although

nmin

can be zero.

Note: nmin, nmax, plotstrt
and plotstep must be
integers

1. If you do not

enter integers, they will be
rounded to integers.

You can select a sequence.

You cannot select its
initial value.

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