Texas Instruments TI-86 - Manual (Page 265)

Chapter 19: Applications
253
19APPS.DOC TI-86, Chap 19, US English Bob Fedorisko Revised: 02/13/01 2:41 PM Printed: 02/13/01 3:05 PM Page 253 of 18 19APPS.DOC TI-86, Chap 19, US English Bob Fedorisko Revised: 02/13/01 2:41 PM Printed: 02/13/01 3:05 PM Page 253 of 18
Next, use the list editor and a degree-three polynomial regression to find an analytic formula in
terms of
x for the characteristic polynomial y1=det(A N x ¹ ident 3) . Create two lists that you can
use to find the analytic formula.
ᕦ In the list editor, create elements for xStat by entering the
expression seq(N,N, L 10,21) in the xStat entry line. seq is on the
MATH MISC menu.
ᕧ Create elements for yStat by attaching the formula "y1(xStat)" to
yStat in the entry line. The expression is evaluated when you
press b or exit the list editor.
ᕨ On the home screen, select Plot1( from the CATALOG and
execute Plot1(2,xStat,yStat,1) to turn on Plot1 as an xyLine plot
using the lists xStat and yStat .
ᕩ Select GRAPH from the GRAPH menu to display Plot1 and y1 on
the graph screen.
µ On the home screen, select P3Reg from the STAT CALC menu.
Execute P3Reg xStat,yStat,y2 to find the explicit characteristic
polynomial in terms of x and store it to y2 .
The cubic regression coefficients stored in the result list PRegC
suggest that a= L1, b=0, c=14, and d=L24. So the characteristic
polynomial seems to be Cp(x)= Lx 3 +14x N24.
To clear the menus from the
graph screen, press
: .