Calculator 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=

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'