Texas Instruments TITANIUM TI-89 - Manual (Page 369)

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(nN1) N .8(u1(nN1))
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