Texas Instruments TI-92 Owners Manual - Page 156

Sequence Graphing

Page 156 highlights

Chapter 9: Sequence Graphing 9 Preview of Sequence Graphing 140 Overview of Steps in Graphing Sequences 141 Differences in Sequence and Function Graphing 142 Setting Axes for Time, Web, or Custom Plots 146 Using Web Plots 147 Using Custom Plots 150 Using a Sequence to Generate a Table 151 This chapter describes how to graph sequences on the TI-89 / TI-92 Plus. Before using this chapter, you should be familiar with Chapter 6: Basic Function Graphing. Sequences are evaluated only at consecutive integer values. The two general types of sequences are: ¦ Nonrecursive - The nth term in the sequence is a function of the independent variable n. Each term is independent of any other terms. In the following example sequence, you can calculate u(5) directly, without first calculating u(1) or any other previous term. u(n) = 2 ù n for n = 1, 2, 3, ... n is always a series of consecutive integers, starting at any positive integer or zero. u(n) = 2 ù n gives the sequence 2, 4, 6, 8, 10, ... Note: A recursive sequence can reference another sequence. For example, u2(n) = nñ +u1(nì 1). ¦ Recursive - The nth term is defined in relation to one or more previous terms, represented by u(nì 1), u(nì 2), etc. In addition to previous terms, a recursive sequence may also be defined in relation to n (such as u(n) = u(nì 1) + n). In the following example sequence, you cannot calculate u(5) without first calculating u(1), u(2), u(3), and u(4). The first term is undefined u(n) = 2 ù u(nì 1) for n = 1, 2, 3, ... since it has no previous term. So you must specify an initial value to use for the first term. Using an initial value of 1: u(n) = 2 ù u(nì 1) gives the sequence 1, 2, 4, 8, 16, ... The number of initial values you need to specify depends on how deep the recursion goes. For example, if each term is defined in relation to the previous two terms, you must specify initial values for the first two terms. Chapter 9: Sequence Graphing 139

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Chapter 9: Sequence Graphing
139
Sequence Graphing
Preview of Sequence Graphing
............................................................
140
Overview of Steps in Graphing Sequences
.........................................
141
Differences in Sequence and Function Graphing
..............................
142
Setting Axes for Time, Web, or Custom Plots
....................................
146
Using Web Plots
......................................................................................
147
Using Custom Plots
................................................................................
150
Using a Sequence to Generate a Table
................................................
151
This chapter describes how to graph sequences on the
TI
-
89 / TI
-
92 Plus
. Before using this chapter, you should be familiar
with Chapter 6: Basic Function Graphing.
Sequences are evaluated only at consecutive integer values. The
two general types of sequences are:
¦
Nonrecursive
— The
n
th term in the sequence is a function
of the independent variable
n
.
Each term is independent of any other terms. In the following
example sequence, you can calculate
u(5)
directly, without
first calculating
u(1)
or any other previous term.
u(n) = 2
ù
n
for
n = 1, 2, 3, ...
u(n) = 2
ù
n
gives the sequence
2, 4, 6, 8, 10, ...
¦
Recursive
— The
n
th term is defined in relation to one or
more previous terms, represented by
u(n
ì
1)
,
u(n
ì
2)
, etc. In
addition to previous terms, a recursive sequence may also be
defined in relation to
n
(such as
u(n) = u(n
ì
1) + n
).
In the following example sequence, you cannot calculate
u(5)
without first calculating
u(1)
,
u(2)
,
u(3)
, and
u(4)
.
u(n) = 2
ù
u(n
ì
1)
for
n = 1, 2, 3, ...
Using an initial value of 1:
u(n) = 2
ù
u(n
ì
1)
gives the sequence
1, 2, 4, 8, 16, ...
The number of initial values you need to specify depends on
how deep the recursion goes. For example, if each term is
defined in relation to the previous two terms, you must specify
initial values for the first two terms.
9
Note:
A recursive sequence
can reference another
sequence. For example,
u2(n) = n
ñ
+u1(n
ì
1).
n is always a series of
consecutive integers,
starting at any positive
integer or zero.
The first term is undefined
since it has no previous term.
So you must specify an initial
value to use for the first term.