Texas Instruments TITANIUM TI-89 User Manual

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106

2. Display and clear the

Y= Editor

. Then

define the 1st-order differential equation:

y1'(t)=.001y1…(100Ny1)

Press

p to enter the … shown above. Do

not use implied multiplication between the
variable and parentheses. If you do, it is
treated as a function call.

Leave the initial condition

yi1

blank.

Note:

With y1' selected, the device will

graph the

solution curve, not the

derivative y1'.

Press

8 # , 8 ¸ ¸ .001 Y1

p c 100 | Y1 d ¸

3. Display the

GRAPH FORMATS

dialog box.

Then set

Axes = ON

Labels = ON

Solution

Method = RK

, and

Fields = SLPFLD

Note:

To graph one differential equation,

Fields must be set to

SLPFLD

FLDOFF

Fields=DIRFLD

, an error occurs when

you graph.

Press

8 Í D D B 2 D D B 2 D B 1

D B 1 ¸

Steps and keystrokes

Display