Texas Instruments TI-89 Titanium - Page 203

Appendix A: Functions and Instructions 197
If Boolean expression Then
block1
Else
block2
EndIf
If Boolean expression evaluates to true, executes
block1 and then skips block2 .
If
Boolean expression evaluates to false, skips
block1 but executes block2 .
block1 and block2 can be a single statement.
Program segment:
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:If x<0 Then
: Disp "x is negative"
: Else
: Disp "x is positive or
zero"
:EndIf
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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+2 i ) ¸ 2
imag(z)
¸ 0
imag(x+
i y) ¸ y
imag( list1 ) ⇒ list
Returns a list of the imaginary parts of the
elements.
imag({ë 3,4ë i , i }) ¸ {0 ë 1 1}
imag( matrix1 ) ⇒ matrix
Returns a matrix of the imaginary parts of the
elements.
imag([a,b; i c, i d]) ¸ [
0 0
c d
]
Indirection See #(), page 273.
Input CATALOG
Input
Pauses the program, displays the current Graph
screen, and lets you update variables
xc and yc
(also rc and q c 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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