Texas Instruments TI-86 - Manual (Page 153)

Chapter 10: Differential Equation Graphing
141
10DIFFEQ.DOC TI-86, Chap 10, US English Bob Fedorisko Revised: 02/13/01 2:28 PM Printed: 02/13/01 3:02 PM Page 141 of 20 10DIFFEQ.DOC TI-86, Chap 10, US English Bob Fedorisko Revised: 02/13/01 2:28 PM Printed: 02/13/01 3:02 PM Page 141 of 20 10DIFFEQ.DOC TI-86, Chap 10, US English Bob Fedorisko Revised: 02/13/01 2:28 PM Printed: 02/13/01 3:02 PM Page 141 of 20
Graphing in DirFld Format
ᕡ Display the mode screen and set DifEq
graphing mode.
- m # # #
# " " " b
ᕢ Display the format screen and set DirFld
graphing format.
6 / & #
# # # # " b
ᕣ Display the equation editor and store the
transformed system of differential
equations for y''=
Ly to the equation editor,
substituting Q1 for y and Q2 for y'.
& ' 2 # a ' 1
ᕤ Display the initial conditions editor and enter
the initial conditions if you want a specific
solution. To enter a list of initial conditions,
use
{ and } from the LIST menu.
- g - ”
&
1 P 2 P 5 '
# & -~ P 4
P 5 ` 75 '
ᕥ Display the axes editor and enter the two
equation variables for which you want to
solve. You must omit the prime mark (
' ).
ᕦ Accept or change fldRes (resolution).
- h & 1 #
& 2
ᕧ Select ZSTD from the GRAPH ZOOM menu
to set the standard window variable values
and display the graph.
ᕨ Clear the GRAPH menu from the screen.
. / ( )
:
In DifEq graphing mode, t is
the independent variable and
Q'
n is the dependent variable,
where n ‚ 1 and  9.
In the example, the default
window variable values are
set initially.
When DirFld field format is
selected, x=Q1, y=Q2,
dTime=0
, and fldRes=15 are
the default axes settings.
Since t is not part of the
equation, dTime is ignored.