Texas Instruments TI-89 - Page 463

446 Appendix A: Functions and Instructions
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 446 of 132
expand(expression1,
[
var
]
)
also distributes
logarithms and fractional powers regardless
of
var
. For increased distribution of
logarithms and fractional powers, inequality
constraints might be necessary to guarantee
that some factors are nonnegative.
expand(expression1,
[
var
]
)
also distributes
absolute values,
sign()
, and exponentials,
regardless of
var
.
Note:
See also
tExpand()
for trigonometric
angle-sum and multiple-angle expansion.
ln(2x
ù
y)+‡(2x
ù
y)
¸
ln(2
ø
x
ø
y) +
‡
(2
ø
x
ø
y)
expand(ans(1))
¸
ln(x
ø
y) +
‡
2
ø
‡
(x
ø
y) + ln(2)
expand(ans(1))|y>=0
¸
ln(x) +
‡
2
ø
‡
x
ø
‡
y + ln(y) + ln(2)
sign(x
ù
y)+abs(x
ù
y)+
e
^(2x+y)
¸
e
2
ø
x+y
+ sign(x
ø
y) + |x
ø
y|
expand(ans(1))
¸
sign(x)
ø
sign(y) + |x|
ø
|y|+ (
e
x
)
2
ø
e
y
expr()
MATH/String menu
expr(string)
⇒
expression
Returns the character string contained in
string
as an expression and immediately
executes it.
expr("1+2+x^2+x")
¸
x
ñ
+ x + 3
expr("expand((1+x)^2)")
¸
x
ñ
+ 2
ø
x +
1
"Define cube(x)=x^3"
!
funcstr
¸
"Define cube(x)=x^3"
expr(funcstr)
¸
Done
cube(2)
¸
8
ExpReg
MATH/Statistics/Regressions menu
ExpReg list1, list2
[
, [
list3
] [,
list4, list5
]
]
Calculates the exponential regression and
updates all the system statistics variables.
All the lists must have equal dimensions
except for
list5
.
list1
represents xlist.
list2
represents ylist.
list3
represents frequency.
list4
represents category codes.
list5
represents category include list.
Note:
list1
through
list4
must be a variable
name or c1–c99 (columns in the last data
variable shown in the Data/Matrix Editor).
list5
does not have to be a variable name and
cannot be c1–c99.
In function graphing mode:
{1,2,3,4,5,6,7,8}
!
L1
¸
{1 2
...
}
{1
,2,2,2,3,4,5,7
}
!
L2
¸
{1 2
...
}
ExpReg L
1
,L2
¸
Done
S
h
owStat
¸
¸
Regeq(x)"y1(x)
¸
Done
NewP
l
ot
1
,
1
,L
1
,L2
¸
Done
¥%