Texas Instruments Titanium TI-89, User Manual

Page: 854 / 977

Appendix A: Functions and Instructions 851
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(a
ù
x^2+b
ù
x+c=0,x)
¸
x =
b
ñ -
4
ø
a
ø
c-b
2
ø
a
or x =
ë
( b ñ - 4 ø a ø c+b)
2 ø 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((x
ì
a)
e
^(x)=
ë
x
ù
(x
ì
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)(x
ì
1)/(x
ì
1)+x
ì
3
¸
2
ø
x
ì
2
solve(entry(1)=0,x) ¸ x = 1
entry(2)|ans(1) ¸ undef
limit(entry(3),x,1)
¸
0
For inequalities of types
‚
,
c
, <, or >, explicit solutions
are unlikely unless the inequality is linear and contains
only
var
.
solve(5x ì 2 ‚ 2x,x) ¸ x ‚ 2/3
For the
EXACT
setting of the
Exact/Approx
mode,
portions that cannot be solved are returned as an
implicit equation or inequality.
exact(solve((x
ì
a)
e
^(x)=
ë
x
ù
(x ì a),x)) ¸
e
x
+ x = 0 or x = a