Graphing Phase Plots - Texas Instruments TI-82 STATS Manual Book

Graphing Phase Plots

Graphing with uv,
vw, and uw
Example:
Predator-Prey
Model
The phase-plot axes settings
between two sequences. To select a phase-plot axes setting,
press y [
FORMAT
, and then press Í.
uw
Axes Setting
uv
vw
uw
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 wolves and rabbits, with initial populations of
200 rabbits (
u(nMin)
These are the variables (given values are in parentheses):
R = number of rabbits
M = rabbit population growth rate without wolves
K = rabbit population death rate with wolves
W = number of wolves
G = wolf population growth rate with rabbits
D = wolf population death rate without rabbits
= time (in months)
n
R = R (1+MNKW
n nN1
W = W (1+GR
n nN1
1. Press o in
Seq
Define the sequences and initial values for R
shown below. Enter the sequence R
sequence W as
n
, , and
uv vw
], press ~ until the cursor is on
x-axis
u(n)
v(n)
u(n)
) and 50 wolves (
v(nMin)
)
nN1
ND)
nN1
mode to display the sequence
.
v(n)
Sequence Graphing 6–13
show relationships
uw
, , or
uv vw
y-axis
v(n)
w(n)
w(n)
).
(.0002)
editor.
Y=
and W as
n n
as and enter the
u(n)
n
(.05)
(.001)
(.03)