Texas Instruments TI-89, TI-92

Chapter 11: Differential Equation Graphing 177

11DIFFEQ.DOC TI-89/TI-92 Plus: Differential Equation (English) Susan Gullord Revised: 02/23/01 11:04 AM Printed: 02/23/01 2:15 PM Page 177 of 26

Steps

TI-89

Keystrokes

›

TI-92 Plus

Keystrokes Display

6. Return to the Y= Editor and

enter an initial condition:

yi1=10

¥#

¸10

¥#

¸10

7. Return to the Graph screen.

Initial conditions entered in the

Y= Editor always occur at t0. The

graph begins at the initial condition

and plots to the right. Then it plots to

the left.

¥% ¥%

8. Return to the Y= Editor and

change yi1 to enter two initial

conditions as a list:

yi1={10,20}

¥#C

¸2[

10b202\

¥#C

¸2[

10b202\

9. Return to the Graph screen. ¥% ¥%

10. To select an initial condition

interactively, press:

TI-89: 2Š

TI-92 Plus: Š

When prompted, enter t=40 and

y1=45.

When selecting an initial condition

interactively, you can specify a value

for t other than the t0 value entered in

the Y= Editor or Window Editor.

Instead of entering t and y1 after

pressing TI-89:

2Š

TI-92 Plus:

, you can move the

cursor to a point on the screen and

then press

You can use

…

to trace curves for

initial conditions specified in the Y=

Editor. However, you cannot trace the

curve for an initial condition selected

interactively.

2Š

40¸

45¸

40¸

45¸

The initial condition is

marked with a circle.