Calculator User Manual

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
©
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:
©
: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
©
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
3,4
ë
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
]
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:
©
:
¦
Get
1
0 points from t
h
e Grap
h
Screen
:For i,
1
,
1
0
: Input
: xc
!
XLIST
[
i
]
: yc
!
YLIST
[
i
]
:En
d
For
©
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:
©
:For i,1,9,1
: "Enter x" & string(i)
!
str1
: Input str1,#(right(str1,2))
:EndFor
©