Texas Instruments -84 Plus, Manual Book

Page: 172 / 696

Chapter 6: Sequence Graphing 169
Graphing Phase Plots Graphing Phase Plots Graphing Phase Plots Graphing Phase Plots
Graphing with uv, vw, and uw
Graphing with uv, vw, and uw Graphing with uv, vw, and uw
Graphing with uv, vw, and uw
The phase-plot axes settings
uv
,
vw
, and
uw
show relationships between two
sequences. To select a phase-plot axes setting, press
y .
, press
~
until the
cursor is on
uv
,
vw
, or
uw
, and then press
Í
.
Example: Predator-Prey Model
Example: Predator-Prey Model Example: Predator-Prey Model
Example: Predator-Prey Model
Use the predator-prey model to determine the regional populations of a predator and its
prey that would maintain population equilibrium for the two species.
This example uses the model to determine the equilibrium populations of foxes and
rabbits, with initial populations of 200 rabbits (
u(
n
Min)
) and 50 foxes (
v(
n
Min)
).
These are the variables (given values are in parentheses):
Axes Setting x-axis y-axis
uv u( n ) v( n )
vw v(
n
) w(
n
)
uw u( n ) w( n )
R = number of rabbits
M = rabbit population growth rate without foxes (.05)
K = rabbit population death rate with foxes (.001)