Texas Instruments TI-89 Voyage 200, User Manual

Page: 438 / 1008

Differential Equation Graphing 438
8. Return to the Y= Editor. Press:
,
9
— or —
@ 8
Í
Set
Fields = DIRFLD
.
Note:
In this example,
DIRFLD
is used for
two related differential equations that do
not represent a 2nd-order equation.
9. Press:
@ 2
‰
Confirm that the axes are set as shown.
10. In the Y= Editor, clear the initial conditions
for
yi1
and
yi2
.
11. Return to the Graph screen, which
displays only the direction field.
12. To graph a family of solutions, return to
the Y= Editor and enter the initial
conditions shown below.
yi1={2,6,7}
and
yi2={5,12,18}
Note:
Use a list to specify more than one
initial condition.