Texas Instruments PLUS TI-89 - Manual (Page 474)

Appendix A: Functions and Instructions 457
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 457 of 132
If Boolean expression1 Then
block1
ElseIf Boolean expression2 Then
block2
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ElseIf Boolean expressionN Then
blockN
EndIf
Allows for program branching. If Boolean
expression1 evaluates to true, executes block1 .
If Boolean expression1 evaluates to false,
evaluates Boolean expression2 , etc.
Program segment:
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:If choice=1 Then
: Goto option1
: ElseIf choice=2 Then
: Goto option2
: ElseIf choice=3 Then
: Goto option3
: ElseIf choice=4 Then
: Disp "Exiting Program"
: Return
:EndIf
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imag() MATH/Complex menu
imag( expression1 ) ⇒ expression
imag( expression1 ) returns the imaginary part
of the argument.
Note: All undefined variables are treated as
real variables. See also real() .
imag(1+2i) ¸ 2
imag(z) ¸ 0
imag(x+iy) ¸ y
imag( list1 ) ⇒ list
Returns a list of the imaginary parts of the
elements.
imag({л 3,4л i,i}) ¸ {0 ë 1 1}
imag( matrix1 ) ⇒ matrix
Returns a matrix of the imaginary parts of the
elements.
imag([a,b;ic,id ]) ¸ [
0 0
c d
]
Input CATALOG
Input
Pauses the program, displays the current
Graph screen, and lets you update variables
xc
and yc (also rc and qc for polar coordinate
mode) by positioning the graph cursor.
When you press ¸, the program resumes.
Program segment:
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:¦ Get 10 points from the Graph
Screen
:For i,1,10
: Input
: xc! XLIST[i]
: yc! YLIST[i]
:EndFor
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Input [ promptString ,] var
Input [ promptString ], var pauses the program,
displays promptString on the Program I/O
screen, waits for you to enter an expression,
and stores the expression in variable
var .
If you omit promptString , “?” is displayed as a
prompt.
Program segment:
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:For i,1,9,1
: "Enter x" & string(i)! str1
: Input str1,#(right(str1,2))
:EndFor
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