Texas Instruments TI-89 Titanium Short User Manual page 210

Local
CATALOG
var1 var2
Local [,
Declares the specified
Those variables exist only during evaluation of a
program or function and are deleted when the
program or function finishes execution.
Note: Local variables save memory because they
only exist temporarily. Also, they do not disturb
any existing global variable values. Local
variables must be used for
temporarily saving values in a multi-line function
since modifications on global variables are not
allowed in a function.
Lock
CATALOG
var1 var2
Lock [,
Locks the specified variables. This prevents you
from accidentally deleting or changing the
variable without first using the unlock instruction
on that variable.
In the example to the right, the variable L1 is
locked and cannot be deleted or modified.
Note: The variables can be unlocked using the
Unlock
log()
CATALOG
expression1
log(
) ⇒
list1
log(
Returns the base-10 logarithm of the argument.
For a list, returns the base-10 logs of the
elements.
squareMatrix1
log(
Returns the matrix base-10 logarithm of
squareMatrix1
the base-10 logarithm of each element. For
information about the calculation method, refer
to
cos()
squareMatrix1
always contains floating-point numbers.
204
var3 ...
] [, ]
as local variables.
vars
loops and for
For
] ...
command.
) ⇒
expression
list
) ⇒
squareMatrix
not
. This is the same as calculating
.
must be diagonalizable. The result
Program listing:
:prgmname()
:Prgm
:Local x,y
:Input "Enter x",x
:Input "Enter y",y
:Disp xù y
:EndPrgm
x y
Note: and do not exist after the program
executes.
{1,2,3,4}! L1 ¸
Lock L1 ¸
DelVar L1 ¸
Error: Variable is locked or protected
log(2.0) ¸
If complex format mode is
log({ë 3,1.2,5}) ¸
Error: Non-real result
If complex format mode is
log({ë 3,1.2,5}) ¸
ln(3)
{
+
ln(10) ln(10)
In Radian angle mode and Rectangular
complex format mode:
log([1,5,3;4,2,1;6,ë 2,1]) ¸

.795...+.753...øi

.194...ì.315...øi

ë.115...ì.904...øi .488...+.777...øi ...
Appendix A: Functions and Instructions
{1,2,3,4}
Done
.301
:
REAL
:
RECTANGULAR
p ln(5)
øi .079...
ln(10)
.003...ì.647...øi ...
.462...+.270øi
...
}


...
