Chapter 17: Activities
312
After you execute the program above, you can recall and display the picture with the instruction
RecallPic 6
.
Graphing Cobweb Attractors
Problem
Using
Web
format, you can identify points with attracting and repelling behavior in sequence
graphing.
Procedure
1. Press
z
. Select
Seq
and the default mode settings. Press
y
.
. Select
Web
format
and the default format settings.
2. Press
o
. Clear all functions and turn off all stat plots. Enter the sequence that corresponds to
the expression Y = K X(1
N
X).
u(
n
)=Ku(
n
N
1)(1
N
u(
n
N
1))
u(
n
Min)=.01
:For(K,1,3000)
:rand
!
N
Beginning of
For
group.
:If N
1
à
3
:Then
:.5X
!
X
:.5Y
!
Y
:End
If/Then
group
:If 1
à
3 <N and N
2
à
3
:Then
:.5(.5+X)
!
X
:.5(1+Y)
!
Y
:End
If/Then
group.
:If 2
à
3 <N
:Then
:.5(1+X)
!
X
:.5Y
!
Y
:End
If/Then
group.
:Pt-On(X,Y)
:End
:StorePic 6
Draw point.
End of
For
group.
Store picture.
