Texas Instruments PLUS TI-89 - Manual (Page 194)

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
³
TI-89
Keystrokes
›
TI-92 Plus
Keystrokes Display
6. Return to the Y= Editor and
enter an initial condition:
yi1=10
¥ #
¸ 1 0
¸ ¥ #
¸ 1 0
¸
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 [
1 0 b 2 0 2 \
¸ ¥ # C
¸ 2 [
1 0 b 2 0 2 \
¸
9. Return to the Graph screen. ¥ % ¥ %
10. To select an initial condition
interactively, press:
TI - 89 : 2 Š
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: 2 Š
TI - 92 Plus: Š , 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.
2 Š
4 0 ¸
4 5 ¸ Š
4 0 ¸
4 5 ¸
The initial condition is
marked with a circle.