Texas TI-86 用户手册

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 140 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 140 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 140 of 20

�   Display the axes editor and enter the

equation variable for which you want to
solve. (Do not set 

.)

�   Accept or change 

 (resolution).

) & 

�   Display the graph. With the default

window variable values set, the slope
fields for this graph are not very
illustrative.

- i

�   Change the window variables 

, 

,

, and 

.

�   Select 

 from the 

GRAPH

 menu to re-

plot the graph and activate the trace cursor.
Trace the solution. The trace cursor
coordinates for 

 and 

 are displayed.

' # # # # 

# 

 # # 

 # 

/ )

" and !

On the TI

-86, to enter a second-order or higher (up to ninth-order) differential equation, you

must transform it to a system of first-order differential equations. For example, to enter the
second-order differential equation y''= 

y, you must transform it to two first-order

differential equations, as shown in the chart below.

Differentiate...

 Define the variables as...

 And then substitute:

=y'

=y

 (since 

=y'=

)

=y''

=y'

In 

 field format, 

 is

always true; 

 and

 are the default

axes settings.