Texas Instruments TI-89 Voyage 200, User Manual

Page: 369 / 1008

Sequence Graphing 369
Example: Oscillation Example: Oscillation Example: Oscillation Example: Oscillation
This example shows how the initial value can affect a sequence.
1. On the Y= Editor (
8 #
), use the same sequence defined in the divergence
example: u1(n) = 3.2u1(n
N
1)
N
.8(u1(n
N
1))
2
. Set initial value ui1 = 0.5.
2. Set
Axes = TIME
.
3. On the Window Editor (
8 $
), set the Window variables.
5. On the Y= Editor, set
Axes = WEB
and
Build Web = AUTO
.
7. Regraph the sequence.
The web plot shows how quickly the
sequence diverges to large negative
values.
nmin=1
nmax=100
plotstrt=1
plotstep=1 xmin=0
xmax=100
xscl=10 ymin=0
ymax=5
yscl=1
4. Graph the sequence (
8 %
).
Note:
Compare this graph with the
divergence example. This is the same
sequence with a different initial value.
y=3.2x N .8x
2
u(n
N
1)
u(n
y=x
u(n)
n