Texas Instruments PLUS TI-89 - Manual (Page 586)

Appendix B: Reference Information 569
8992APPB DOC TI-89/TI-92 Plus:8992appb doc (English) Susan Gullord Revised: 02/23/01 1:54 PM Printed: 02/23/01 2:24 PM Page 569 of 34
The indirection operator (#) converts a string to a variable or
function name. For example,
#(“x”&”y”&”z”) creates the variable name
xyz . Indirection also allows the creation and modification of
variables from inside a program. For example, if 10 ! r and “r” ! s1 , then
#s1=10 .
Post operators are operators that come directly after an argument,
such as 5!, 25%, or 60ó15' 45". Arguments followed by a post operator
are evaluated at the fourth priority level. For example, in the
expression
4^3! , 3! is evaluated first. The result, 6 , then becomes the
exponent of 4 to yield 4096 .
Exponentiation (^) and element-by-element exponentiation (.^) are
evaluated from right to left. For example, the expression
2^3^2 is
evaluated the same as 2^(3^2) to produce 512 . This is different from
(2^3)^2 , which is 64 .
To enter a negative number, press · followed by the number. Post
operations and exponentiation are performed before negation. For
example, the result of
ë x 2 is a negative number, and л 9 2 = л 81 . Use
parentheses to square a negative number such as ( ë 9) 2 to produce
81 . Note also that negative 5 ( ë 5) is different from minus 5 ( ì 5) , and
ë 3! evaluates as ë (3!) .
The argument following the “with” (|) operator provides a set of
constraints that affect the evaluation of the argument preceding the
“with” operator.
Indirection
Post Operators
Exponentiation
Negation
Constraint (|)