TI -86 用户手册

19APPS.DOC   TI-86, Chap 19, US English   Bob Fedorisko   Revised: 02/13/01 2:41 PM   Printed: 02/13/01 3:05 PM   Page 259 of 18

19APPS.DOC   TI-86, Chap 19, US English   Bob Fedorisko   Revised: 02/13/01 2:41 PM   Printed: 02/13/01 3:05 PM   Page 259 of 18

�   Select 

 from the 

GRAPH

 menu to plot the graph of the

two populations over time.

�   To see the direction field of the phase-plane solution, select

 from the 

GRAPH

 screen, and then set 

 field

format.

�   Select 

 from the 

GRAPH

 menu and delete the values for

 and 

.

�   Select 

 from the 

GRAPH

 menu to display the direction

field of the phase-plane solution.

�   To see a family of specific phase-plane solutions on top of the

direction field, select 

 from the 

GRAPH

 menu, and then

enter lists for 

 and 

 as shown.

쐅 Select 

 from the 

GRAPH

 menu to display the graph with

the trace cursor.

쐈 Press 

 to see how many foxes and how many rabbits are alive at

. (Round the values of 

 (foxes) and 

 (rabbits) to whole

numbers.) How many foxes and rabbits are alive at 

? at 

?

On what value of 

 and 

 do the phase-plane orbits seem to

converge? What is the significance of this value?