Texas Instruments PLUS TI-89 - Manual (Page 476)

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(л 1.234) ¸ л 1.
iPart({3/2,л 2.3,7.003}) ¸
{1 л 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) ¸ false
Function to find the next prime after a
specified number:
Define nextPrim(n)=Func:Loop:
n+1! n:if isPrime(n):return n:
EndLoop:EndFunc ¸ 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:
©
:Lbl lbl1
:InputStr "Enter password",
str1
:If str1
ƒpassword
: Goto lbl1
:Disp "Welcome to ..."
©