Texas Instruments PLUS TI-89 - Manual (Page 451)

434 Appendix A: Functions and Instructions
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 434 of 132
Define progName ( arg1Name, arg2Name, ... ) = Prgm
block
EndPrgm
Creates progName as a program or
subprogram, but cannot return a result using
Return . Can execute a block of multiple
statements.
block can be either a single statement or a
series of statements separated with the “:”
character.
block also can include expressions
and instructions (such as If , Then , Else , and
For ) without restrictions.
Note: It is usually easier to author and edit a
program block in the Program Editor rather
than on the entry line.
Define listinpt()=prgm:Local
n,i,str1,num:InputStr "Enter
name of list",str1:Input "No.
of elements",n:For
i,1,n,1:Input "element
"&string(i),num:
num! #str1[i]:EndFor:EndPrgm
¸
Done
listinpt() ¸Enter name of list
DelFold CATALOG
DelFold folderName1 [, folderName2 ] [, folderName3 ] ...
Deletes user-defined folders with the names
folderName1 , folderName2, etc. An error
message is displayed if the folders contain
any variables.
Note: You cannot delete the main folder.
NewFold games ¸ Done
(creates the folder games )
DelFold games ¸ Done
(deletes the folder games )
DelVar CATALOG
DelVar var1 [, var2 ] [, var3 ] ...
Deletes the specified variables from memory.
2! a ¸ 2
(a+2)^2 ¸ 16
DelVar a ¸ Done
(a+2)^2 ¸ (a + 2)ñ
deSolve() MATH/Calculus menu
deSolve( 1stOr2ndOrderOde , independentVar ,
dependentVar ) ⇒
a general solution
Returns an equation that explicitly or
implicitly specifies a general solution to the
1st- or 2nd-order ordinary differential
equation (ODE). In the ODE:
•
Use a prime symbol ( ' , press 2 È ) to
denote the 1st derivative of the dependent
variable with respect to the independent
variable.
•
Use two prime symbols to denote the
corresponding second derivative.
The ' symbol is used for derivatives within
deSolve() only. In other cases, use d ( ) .
The general solution of a 1st-order equation
contains an arbitrary constant of the form
@k, where k is an integer suffix from 1
through 255. The suffix resets to 1 when you
use
ClrHome or ƒ 8: Clear Home . The
solution of a 2nd-order equation contains two
such constants.
Note: To type a prime symbol ( ' ), press
2 È .
deSolve(y''+2y'+y=x^2,x,y) ¸
y=(@1шx+@2)шe ë x +xс м 4шx+6
right(ans(1))! temp ¸
(@1шx+@2)шe ë x +xс м 4шx+6
d (temp,x,2)+2ùd(temp,x)+tempìx^2
¸ 0
DelVar temp ¸ Done