Texas Instruments TI-89 - Page 505

488 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 488 of 132
rand()
MATH/Probability menu
rand([
n
])
⇒
expression
n
is an integer
ƒ
zero.
With no parameter, returns the next random
number between 0 and 1 in the sequence.
When an argument is positive, returns a
random integer in the interval [1,
n
].
When an argument is negative, returns a
random integer in the interval [
ë
n
,
ë
1].
RandSeed 1147
¸
Done
rand()
¸
.158
...
ran
d(
6
)
¸
5
ran
d(
ë
1
00
)
¸
ë
49
randMat()
MATH/Probability menu
randMat(
numRows
,
numColumns
)
⇒
matrix
Returns a matrix of integers between -9 and 9
of the specified dimension.
Both arguments must simplify to integers.
RandSeed 1147
¸
Done
randMat(3,3)
¸






8
ë
3 6
ë
2 3
ë
6
0 4
ë
6
Note: The values in this matrix will
change each time you press
¸
.
randNorm
()
MATH/Probability menu
randNorm(
mean
,
sd
)
⇒
expression
Returns a decimal number from the specific
normal distribution. It could be any real
number but will be heavily concentrated in
the interval [
mean
-3
ù
sd
,
mean
+3
ù
sd
].
RandSeed 1147
¸
Done
randNorm(0,1)
¸
.492
...
randNorm(3,4.5)
¸ ì
3.543
...
randPoly
()
MATH/Probability menu
randPoly(
var
,
order
)
⇒
expression
Returns a polynomial in
var
of the specified
order. The coefficients are random integers
in the range
ë
9 through 9. The leading
coefficient will not be zero.
order
must be 0–99.
RandSeed 1147
¸
Done
ran
d
Po
l
y
(
x,5
)
¸
ë
2
ø
x
5
+3
ø
x
4
ì
6
ø
x
3
+4
ø
x
ì
6
RandSeed
MATH/Probability menu
RandSeed
number
If
number
= 0, sets the seeds to the factory
defaults for the random-number generator. If
number
ƒ
0, it is used to generate two seeds,
which are stored in system variables
seed1
and
seed2
.
RandSeed 1147
¸
Done
rand()
¸
.158
...
RclGDB
CATALOG
RclGDB
GDBvar
Restores all the settings stored in the Graph
database variable
GDBvar
.
For a listing of the settings, see
StoGDB
.
Note: It is necessary to have something
saved in
GDBvar
before you can restore it.
RclGDB GDBvar
¸
Done
(Sets the random-number seed.)