Texas Instruments Titanium TI-89, Руководство пользователя

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Appendix A: Functions and Instructions 769
cFactor( expression1,var )
returns
expression1
factored
with respect to variable
var
.
expression1
is factored as much as possible toward
factors that are linear in
var
, with perhaps non-real
constants, even if it introduces irrational constants
or subexpressions that are irrational in other
variables.
The factors and their terms are sorted with
var
as
the main variable. Similar powers of
var
are
collected in each factor. Include
var
if factorization is
needed with respect to only that variable and you
are willing to accept irrational expressions in any
other variables to increase factorization with respect
to
var
. There might be some incidental factoring with
respect to other variables.
cFactor(a^3
ù
x^2+a
ù
x^2+a^3+a,x)
¸
a
ø
(a
ñ
+ 1 )
ø
(x +
ë i
)
ø
(x +
i
)
cFactor(x^2+3,x)
¸
(x +
‡
3
ø
i )
ø
(x +
ë ‡
3
ø
i )
cFactor(x^2+a,x) ¸
(x +
‡
a
øë
i )
ø
(x +
‡
a
ø
i )
For the
AUTO
setting of the
Exact/Approx
mode,
including
var
also permits approximation with
floating-point coefficients where irrational
coefficients cannot be explicitly expressed concisely
in terms of the built-in functions. Even when there is
only one variable, including
var
might yield more
complete factorization.
Note: See also
factor()
.
cFactor(x^5+4x^4+5x^3 ì 6x ì 3)
¸
x
5
+ 4
ø
x
4
+ 5
ø
x
3 ì
6
ø
x
ì
3
cFactor(ans(1),x)
¸
(x
ì
.965)
ø
(x +.612)
ø
(x + 2.13)
ø
(x + 1.11
ì
1.07
ø i
)
ø
(x + 1.11 + 1.07 ø i )
char()
MATH/String menu
char( integer )
⇒
character
Returns a character string containing the character
numbered
integer
from the
TI-89 Titanium/Voyage™ 200 character set. See
Appendix B for a complete listing of character
codes. The valid range for
integer
is 0–255.
char(38)
¸
"&"
char(65)
¸
"A"
checkTmr()
CATALOG
checkTmr( starttime )
⇒
integer
Returns an integer representing the number of
seconds that have elapsed since a timer was
started.
starttime
is an integer returned from the
startTmr()
function.
You can also use a list or matrix of
starttime
integers.
Valid
starttime
integers must fall between 0 and the
current time of the clock. You can run multiple
timers simultaneously.
Note: See also
startTmr()
and
timeCnv()
.
startTmr()
¸
148083315
checkTmr(148083315) 34
startTmr()
!
Timer1
©
startTmr()
!
Timer2
©
checkTmr(Timer1)
!
Timer1Value
©
checkTmr(Timer2)
!
Timer2Value
Circle
CATALOG
Circle
x
,
y
,
r
[ ,
drawMode
]
Draws a circle with its center at window coordinates
(
x
,
y
) and with a radius of
r
.
x
,
y
, and
r
must be real values.
If
drawMode
= 1, draws the circle (default).
If
drawMode
= 0, turns off the circle.
If
drawMode
= -1, inverts pixels along the circle.
Note : Regraphing erases all drawn items. See also
PxlCrcl
.
In a
ZoomSqr
viewing window:
ZoomSqr:Circle 1,2,3
¸
ClockOff
CATALOG
ClockOff
Turns the clock
OFF
.