Operation Manual

Chapter 17: Activities 311
Note: This program uses the default BLUE color (# = 10). See the Draw chapter for available color
options.
After you execute the program above, you can recall and display the picture with the instruction
RecallPic 6.
Note: After you run this program, press y . † † † † ~ ~ ~ † Í to turn on the axes in the
graph screen.
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(1NX).
u(n)=Ku(nN1)(1Nu(nN1))
u(
nMin)=.01
3. Press y 5 to return to the home screen, and then store 2.9 to K.
4. Press p. Set the window variables.
5. Press r to display the graph, and then press ~ to trace the cobweb. This is a cobweb with one
attractor.
6. Change
K to 3.44 and trace the graph to show a cobweb with two attractors.
7. Change
K to 3.54 and trace the graph to show a cobweb with four attractors.
nMin=0
nMax=10
PlotStart=1
PlotStep=1
Xmin=0
Xmax=1
Xscl=1
Ymin=
M.26
Ymax=1.1
Yscl=1