Operation Manual

6-2 Sequence Graphing
8206SEQ.DOC TI-82, Chapter 6, English Bob Fedorisko Revised: 02/09/01 12:49 PM Printed: 02/09/01
12:50 PM Page 2 of 6
Getting Started: Forest and Trees
Getting Started is a fast-paced introduction. Read the chapter for details.
A small forest contains 4000 trees. The new forestry plan is that each year 20% of
the trees will be harvested and 1000 new trees will be planted. Will the forest
disappear? Does it stabilize at a certain number of trees? If so, what is that
number?
1. Press
z
. Press
† † † ~ ~ ~ Í
to
select
Seq
MODE
. Press
† ~ Í
to select
Dot
MODE
.
2. Press
o
. Each year the number of trees is 80
percent of what was there at the end of the prior
year. Press
 ~
2
(to select
iPart
, because
the company will not harvest part of a tree)
£
.8
y
ã
U
n-1 ä
(
2nd
function of
¬
)
¤
to define the
number of trees after each harvest. Press
Ã
1000
to define the replacement trees.
3. Press
p
. Press
†
to move to
U n Start
.
Press
4000
Í
to define the number of trees
at the beginning of the program.
4. Press
† † †
50
Í
to set
n Max=50
to plot
the size of the forest over 50 years.
5. Set the other
WINDOW
variables:
Xmin=0 Ymin=0
Xmax=50 Ymax=6000
Xscl=10 Yscl=1000
6. Press
r
. Tracing begins at
n Min
(before the
forestry program began). Press
~
to trace the
values year-by-year. The values for
n
(year) and
U n
(trees) are displayed at the bottom of the
screen. How many years does it take to stabilize
the size of the forest?