Texas Instruments PLUS TI-89 - Manual (Page 450)

Appendix A: Functions and Instructions 433
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 433 of 132
0b binaryNumber
0h hexadecimalNumber
Without a prefix, integer1 is treated as
decimal. The result is displayed in decimal,
regardless of the
Base mode.
Define CATALOG
Define funcName ( arg1Name, arg2Name, ... ) =
expression
Creates funcName as a user-defined function.
You then can use funcName () , just as you use
built-in functions . The function evaluates
expression using the supplied arguments and
returns the result.
funcName cannot be the name of a system
variable or built-in function.
The argument names are placeholders; you
should not use those same names as
arguments when you use the function.
Note: This form of Define is equivalent to
executing the expression:
expression ! funcName ( arg1Name,arg2Name ).
This command also can be used to define
simple variables; for example,
Define a=3 .
Define g(x,y)=2xì 3y ¸ Done
g(1,2) ¸ ë 4
1! a:2! b:g(a,b) ¸ ë 4
Define h(x)=when(x<2,2x -3,
ë 2x+3) ¸ Done
h(л 3) ¸ л 9
h(4) ¸ ë 5
Define eigenvl(a)=
cZeros(det(identity(dim(a)
[1])
-xù a),x) ¸ Done
eigenvl([л 1,2;4,3]) ¸
{
2ш 3 - 1
11
л (2ш 3 + 1)
11
}
Define funcName ( arg1Name, arg2Name, ... ) = Func
block
EndFunc
Is identical to the previous form of Define ,
except that in this form, the user-defined
function
funcName () can execute a block of
multiple statements.
block can be either a single statement or a
series of statements separated with the “:”
character.
block also can include expressions
and instructions (such as If , Then , Else , and
For ). This allows the function funcName () to
use the Return instruction to return a specific
result.
Note: It is usually easier to author and edit
this form of Function in the program editor
rather than on the entry line.
Define g(x,y)=Func:If x>y Then
:Return x:Else:Return y:EndIf
:EndFunc ¸
Done
g(3,ë 7) ¸ 3
A binary number can have up to
32 digits. A hexadecimal number
can have up to 8.
Zero, not the letter O, followed by b or h.