Texas Instruments PLUS TI-89 - Manual (Page 520)

Appendix A: Functions and Instructions 503
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 503 of 132
SinReg MATH/Statistics/Regressions menu
SinReg list1 , list2 [ , [ iterations ] , [ period ] [, list3 , list4 ] ]
Calculates the sinusoidal regression and
updates all the system statistics variables.
All the lists must have equal dimensions
except for
list4 .
list1 represents xlist.
list2 represents ylist.
list3 represents category codes.
list4 represents category include list.
iterations specifies the maximum number of
times (1 through 16) a solution will be
attempted. If omitted, 8 is used. Typically,
larger values result in better accuracy but
longer execution times, and vice versa.
period specifies an estimated period. If
omitted, the difference between values in
list1 should be equal and in sequential order.
If you specify period , the differences between
x values can be unequal.
Note: list1 through list3 must be a variable
name or c1–c99 (columns in the last data
variable shown in the Data/Matrix Editor).
list4 does not have to be a variable name and
cannot be c1–c99.
The output of SinReg is always in radians,
regardless of the angle mode setting.
In function graphing mode:
seq(x,x,1,361,30)! L1 ¸
{1 31 61 …}
{5.5,8,11,13.5,16.5,19,19.5,17,
14.5,12.5,8.5,6.5,5.5}! L2 ¸
{5.5 8 11 …}
SinReg L1,L2 ¸ Done
ShowStat ¸
¸
regeq(x)! y1(x) ¸
Done
NewPlot 1,1,L1,L2 ¸ Done
¥ %
„ 9
solve() MATH/Algebra menu
solve( equation , var ) ⇒ Boolean expression
solve( inequality , var ) ⇒
Boolean expression
Returns candidate real solutions of an equation
or an inequality for
var . The goal is to return
candidates for all solutions. However, there
might be equations or inequalities for which the
number of solutions is infinite.
solve(aù x^2+bù x+c=0,x) ¸
x =
bс -4ш aш c-b
2ø a
or x =
ë ( bс -4ш aш c+b)
2ø a
Solution candidates might not be real finite
solutions for some combinations of values for
undefined variables. ans(1)| a=1 and b=1 and c=1
¸
Error: Non-real result
For the AUTO setting of the Exact/Approx mode,
the goal is to produce exact solutions when
they are concise, and supplemented by iterative
searches with approximate arithmetic when
exact solutions are impractical.
solve((xì a)e^(x)=ë xù (xì a),x)
¸
x = a or x =ë.567...
Due to default cancellation of the greatest
common divisor from the numerator and
denominator of ratios, solutions might be
solutions only in the limit from one or both
sides. (x+1)(xì 1)/(xì 1)+xм 3 ¸
2ш xм 2
solve(entry(1)=0,x) ¸ x = 1
entry(2)|ans(1) ¸ undef
limit(entry(3),x,1) ¸ 0
For inequalities of types ‚, , <, or >, explicit
solutions are unlikely unless the inequality is
linear and contains only
var .
solve(5xì 2 ‚ 2x,x) ¸ x ‚ 2/3