Texas Instruments TITANIUM TI-89 - Manual (Page 912)

912 Appendix A: Functions and Instructions
| (“with”) Í key
expression | Boolean expression1 [ and Boolean
expression2 ] ... [ and Boolean expressionN ]
The “with” (|) symbol serves as a binary operator.
The operand to the left of | is an expression. The
operand to the right of | specifies one or more
relations that are intended to affect the
simplification of the expression. Multiple relations
after | must be joined by a logical “and”.
The “with” operator provides three basic types of
functionality: substitutions, interval constraints,
and exclusions.
x+1| x=3 ¸ 4
x+y| x=sin(y) ¸ sin(y) + y
x+y| sin(y)=x
¸
x + y
Substitutions are in the form of an equality, such
as
x=3 or y=sin(x) . To be most effective, the left
side should be a simple variable. expression |
variable = value will substitute value for every
occurrence of variable in expression .
x^3ì 2x+7! f(x) ¸ Done
f(x)| x=‡(3) ¸ ‡ 3 + 7
(sin(x))^2+2sin(x)ì 6| sin(x)=d ¸
dñ +2dì 6
Interval constraints take the form of one or more
inequalities joined by logical “and” operators.
Interval constraints also permit simplification that
otherwise might be invalid or not computable. solve(x^2ì 1=0,x)|x>0 and x<2 ¸
x = 1
‡ (x)ù ‡(1/x)|x>0 ¸ 1
‡ (x)ù ‡(1/x) ¸
1
x ø x
Exclusions use the “not equals” (/= or ƒ)
relational operator to exclude a specific value
from consideration. They are used primarily to
exclude an exact solution when using
cSolve() ,
cZeros() , fMax() , fMin() , solve() , zeros() , etc.
solve(x^2ì 1=0,x)| xƒ1 ¸ x = ë 1
! (store) § key
expression ! var
list ! var
matrix ! var
expression ! fun_name(parameter1,...)
list ! fun_name(parameter1,...)
matrix ! fun_name(parameter1,...)
If variable var does not exist, creates var and
initializes it to expression , list , or matrix .
If var already exists and if it is not locked or
protected, replaces its contents with expression ,
list , or matrix .
Hint: If you plan to do symbolic computations
using undefined variables, avoid storing anything
into commonly used, one-letter variables such as
a, b, c, x, y, z, etc.
p /4! myvar ¸
p
4
2cos(x)! Y1(x) ¸ Done
{1,2,3,4}! Lst5 ¸ {1 2 3 4}
[1,2,3;4,5,6]! MatG ¸
[
1 2 3
4 5 6
]
"Hello"! str1 ¸ "Hello"
¦ (comment) Program Editor/Control menu or ¥ d key
¦ [ text ]
¦ processes text as a comment line, which can be
used to annotate program instructions.
¦ can be at the beginning or anywhere in the
line. Everything to the right of ¦, to the end of
the line, is the comment.
Program segment:
©
:¦ Get 10 points from the Graph
screen
:For i,1,10 ¦ This loops 10 times
©