Texas Instruments TI-89 Titanium - Page 179

Appendix A: Functions and Instructions 173
4Dec MATH/Base menu
integer1 4Dec ⇒ integer
Converts integer1 to a decimal (base 10) number.
A binary or hexadecimal entry must always have
a 0b or 0h prefix, respectively.
0b10011 4Dec ¸ 19
0h1F
4Dec ¸ 31
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(ë 3)
¸ ë 9
h(4)
¸ ë 5
Define eigenvl(a)=
cZeros(det(identity(dim(a)
[1])-xù a),x)
¸ Done
eigenvl([ë 1,2;4,3])
¸
{
2ø 3 - 1
11
ë (2ø
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.