Texas Instruments TI-89 User Manual - Page 889
tExpand, timeCnv, Title
UPC - 033317196326
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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. tExpand(sin(3f)) ¸ 4ø sin(f)ø (cos(f))ñ ì sin(f) tExpand(cos(aì b)) ¸ cos(a)ø cos(b)+sin(a)ø sin(b) 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. Text CATALOG Text promptString Text "Have a nice day." ¸ Displays the character string promptString dialog Done 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. 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 :Request :Dropdown :EndDlog © "This is a dialog box" "Your name",Str1 "Month you were born", seq(string(i),i,1,12),Var1 Appendix A: Functions and Instructions 889