Texas Instruments Titanium TI-89, User Manual

Page: 792 / 977

Appendix A: Functions and Instructions 789
DrawParm
CATALOG
DrawParm expression1 , expression2
[ , tmin ] [ , tmax ] [ , tstep ]
Draws the parametric equations
expression1
and
expression2
, using
t
as the independent variable.
Defaults for
tmin
,
tmax
, and
tstep
are the current
settings for the Window variables
tmin
,
tmax
, and
tstep
. Specifying values does not alter the window
settings. If the current graphing mode is not
parametric, these three arguments are required.
Note : Regraphing erases all drawn items.
In function graphing mode and
ZoomStd
window:
DrawParm
t
ù
cos(t),t
ù
sin(t),0,10,.1
¸
DrawPol
CATALOG
DrawPol expression [ ,
q
min ] [ ,
q
max ] [ ,
q
step ]
Draws the polar graph of
expression
, using
q
as the
independent variable.
Defaults for
q
min
,
q
max
, and
q
step
are the current
settings for the Window variables
q
min
,
q
max
, and
q
step
. Specifying values does not alter the window
settings. If the current graphing mode is not polar,
these three arguments are required.
Note : Regraphing erases all drawn items.
In function graphing mode and
ZoomStd
window:
DrawPol 5 ù cos(3 ù q ),0,3.5,.1
¸
DrawSlp
CATALOG
DrawSlp x1 , y1 , slope
Displays the graph and draws a line using the
formula
y
ì
y1=slope
ø
(x
ì
x1)
.
Note : Regraphing erases all drawn items.
In function graphing mode and
ZoomStd
window:
DrawSlp 2,3, ë 2 ¸
DropDown
CATALOG
DropDown
titleString
, {
item1String
,
item2String
, ...},
varName
Displays a drop-down menu with the name
titleString
and containing the items
1:
item1String
,
2:
item2String
,
and so forth.
DropDown
must be within a
Dialog...EndDlog
block.
If
varName
already exists and has a value within the
range of items, the referenced item is displayed as
the default selection. Otherwise, the menu’s first
item is the default selection.
When you select an item from the menu, the
corresponding number of the item is stored in the
variable
varName
. (If necessary,
DropDown
creates
varName
.)
See
Dialog
program listing example.