Calculator User Manual

Appendix A: Functions and Instructions 459
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 459 of 132
iPart()
MATH/Number menu
iPart(
number
)
⇒
integer
iPart(
list1
)
⇒
list
iPart(
matrix1
)
⇒
matrix
Returns the integer part of the argument.
For lists and matrices, returns the integer
part of each element.
The argument can be a real or a complex
number.
iPart(
ë
1.234)
¸ ë
1.
iPart({3/2,
ë
2.3,7.003})
¸
{1
ë
2. 7.
}
isPrime()
MATH/Test menu
isPrime(
number
)
⇒
Boolean constant expression
Returns true or false to indicate if
number
is a
whole number
‚
2 that is evenly divisible only
by itself and 1.
If
number
exceeds about 306 digits and has no
factors

1021,
isPrime(
number
)
displays an
error message.
If you merely want to determine if
number
is
prime, use
isPrime()
instead of
factor()
. It is
much faster, particularly if
number
is not
prime and has a second-largest factor that
exceeds about five digits.
IsPrime(5)
¸
true
IsPrime
(
6
)
¸
fa
l
se
Function to find the next prime after a
specified number:
Define nextPrim(n)=Func:Loop:
n+
1
!
n:if isPrime
(
n
)
:return n:
En
d
Loop:En
d
Func
¸
Done
nextPrim(7)
¸
11
Item
CATALOG
Item
itemNameString
Item
itemNameString
,
label
Valid only within a
Custom...EndCustm
or
ToolBar...EndTBar
block. Sets up a drop-down
menu element to let you paste text to the
cursor position (
Custom
) or branch to a label
(
ToolBar
).
Note: Branching to a label is not allowed
within a
Custom
block.
See
Custom
example.
Lbl
CATALOG
Lbl
labelName
Defines a label with the name
labelName
in
the program.
You can use a
Goto
labelName
instruction to
transfer program control to the instruction
immediately following the label.
labelName
must meet the same naming
requirements as a variable name.
Program segment:
©
:L
bl
lbl1
:InputStr "Enter passwor
d
",
str
1
:If str1ƒpassword
: Goto
lbl1
:Disp "We
l
come to ..."
©