Appendix A: Functions and Instructions 159
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^3ùx^2+aùx^2+a^3+a,x)
¸
aø(añ
+ 1)ø(x + ë
i
)ø(x +
i
)
cFactor(x^2+3,x)
¸
(x
+ ‡3ø
i
)ø(x + ë‡3ø
i
)
cFactor(x^2+a,x)
¸
(x
+ ‡aøë
i
)ø(x + ‡aø
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^3ì6xì3)
¸
x
5
+ 4øx
4
+ 5øx
3
ì6øxì3
cFactor(ans(1),x)
¸
(x
ì.965)ø(x +.612)ø(x + 2.13)ø
(x
+ 1.11 ì 1.07ø
i
)ø
(x + 1.11 + 1.07ø
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 ¸
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