Texas Instruments PLUS TI-89 - Manual (Page 437)

420 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 420 of 132
Circle CATALOG
Circle x , y , r [, drawMode ]
Draws a circle with its center at window
coordinates (
x , y ) and with a radius of r .
x , y , and r must be real values.
If drawMode = 1, draws the circle (default).
If drawMode = 0, turns off the circle.
If drawMode = -1, inverts pixels along the
circle.
Note : Regraphing erases all drawn items. See
also PxlCrcl .
In a ZoomSqr viewing window:
ZoomSqr:Circle 1,2,3 ¸
ClrDraw CATALOG
ClrDraw
Clears the Graph screen and resets the Smart
Graph feature so that the next time the Graph
screen is displayed, the graph will be
redrawn.
While viewing the Graph screen, you can
clear all drawn items (such as lines and
points) by pressing † (
ReGraph ) or pressing:
TI-89: 2 ˆ
TI-92 Plus: ˆ
and selecting 1:ClrDraw .
ClrErr CATALOG
ClrErr
Clears the error status. It sets errornum to
zero and clears the internal error context
variables.
The Else clause of the Try...EndTry in the
program should use ClrErr or PassErr . If the
error is to be processed or ignored, use
ClrErr . If what to do with the error is not
known, use PassErr to send it to the next
error handler. If there are no more pending
Try...EndTry error handlers, the error dialog
box will be displayed as normal.
Note: See also PassErr and Try .
Program listing:
:clearerr()
:Prgm
:PlotsOff:FnOff:ZoomStd
:For i,0,238
:
@xù i+xmin! xcord
: Try
: PtOn xcord,ln(xcord)
: Else
: If errornum=800 or
errornum=260 Then
: ClrErr ¦ clear the error
: Else
: PassErr ¦
pass on any other
error
: EndIf
: EndTry
:EndFor
:EndPrgm
ClrGraph CATALOG
ClrGraph
Clears any functions or expressions that
were graphed with the
Graph command or
were created with the Table command. (See
Graph or Table .)
Any previously selected Y= functions will be
graphed the next time that the graph is
displayed.