Texas Instruments Titanium TI-89, Руководство пользователя

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Appendix A: Functions and Instructions 885
|
(“with”)
@ Í
key
H
2 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^3
ì
2x+7
!
f(x)
¸
Done
f(x)| x=
‡
(3)
¸ ‡
3 + 7
(sin(x))^2+2sin(x)
ì
6| sin(x)=d
¸
d
ñ
+2d
ì
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^2 ì 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^2
ì
1=0,x)| x
ƒ
1
¸
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"