Texas Instruments Titanium TI-89 User Manual

Differential Equation Graphing 429
If you select ZoomSqr („ 5), you can see that the phase-plane orbit is actually a circle.
However,
ZoomSqr will change your Window variables.
6. In the Y= Editor, press:
@2 ‰and make sure
Axes = CUSTOM with y1 and y2 as the
axes.
Important: Fields=DIRFLD cannot plot a
time axis. An
Invalid Axes error occurs if
Axes=TIME or if t is set as a CUSTOM axis.
7. In the Window Editor (8$), set
the Window variables.
t0=0
tmax=10
tstep=.1
tplot=0
xmin=
L2
xmax=2
xscl=1
ymin=L2
ymax=2
yscl=1
ncurves=0
diftol=.001
fldres=14
dtime=0
8. Display the Graph screen (8%).
x axis = y1 = y
y axis = y2 = y'

Texas Instruments Titanium TI-89 Specifications

General

Display Type	LCD
Display Resolution	160 x 100 pixels
Memory	188 KB RAM, 2.7 MB Flash ROM
Type	Graphing Calculator
Display	Monochrome
Processor	Motorola 68000
Processor Speed	12 MHz
Power Source	4 AAA batteries
Connectivity	USB
Programming	TI-BASIC, Assembly
Operating System	AMS (Advanced Mathematics Software)