Texas Instruments TITANIUM TI-89 - Manual (Page 889)

Appendix A: Functions and Instructions 889
tExpand() MATH\Algebra\Trig menu
tExpand( expression1 )
⇒ ⇒ ⇒ ⇒ expression
Returns an expression in which sines and cosines
of integer-multiple angles, angle sums, and angle
differences are expanded. Because of the identity
(sin(x))
2 +(cos(x)) 2 =1, there are many possible
equivalent results. Consequently, a result might
differ from a result shown in other publications.
Sometimes tExpand() will accomplish your goals
when the default trigonometric simplification
does not.
tExpand() tends to reverse
transformations done by tCollect() . Sometimes
applying tCollect() to a result from tExpand() ,
or vice versa, in two separate steps simplifies an
expression.
Note: Degree-mode scaling by p/180 interferes
with the ability of tExpand() to recognize
expandable forms. For best results, tExpand()
should be used in Radian mode.
tExpand(sin(3f)) ¸
4ø sin(f)ø (cos(f))с м sin(f)
tExpand(cos(aì b)) ¸
cos(a)ø cos(b)+sin(a)ø sin(b)
Text CATALOG
Text promptString
Displays the character string promptString dialog
box.
If used as part of a Dialog...EndDlog block ,
promptString is displayed inside that dialog box. If
used as a standalone instruction, Text creates a
dialog box to display the string.
Text "Have a nice day." ¸
Done
Then See If, page 830.
timeCnv() CATALOG
timeCnv( seconds ) ⇒ ⇒ ⇒ ⇒ list
Converts seconds to units of time that can be
more easily understood for evaluation. The list is
in {
days,hours,minutes,seconds } format.
Note: See also checkTmr() and startTmr() .
timeCnv(152442117)
{1764 9 1 57}
Title CATALOG
Title titleString , [ Lbl ]
Creates the title of a pull-down menu or dialog
box when used inside a
Toolbar or Custom
construct, or a Dialog...EndDlog block.
Note: Lbl is only valid in the Toolbar construct.
When present, it allows the menu choice to
branch to a specified label inside the program.
Program segment:
©
:Dialog
:Title "This is a dialog box"
:Request "Your name",Str1
:Dropdown "Month you were born",
seq(string(i),i,1,12),Var1
:EndDlog
©