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Electronic Graphing

STAIR

screenshot

A program for Texas Instruments graphing calculators
by Henri Picciotto

See the corresponding worksheets (TI-82/83/84 and TI-89).

More recent version, based on a GeoGebra applet: Stairs.

The activity is based on "STAIR", a simple program I wrote for the TI calculators. (Thanks to Dennis Dougherty for debugging the TI-83/84 version.)

Familiarize yourself with the program by doing the activity yourself. Note that Part II requires students to already know how to use the STAT EDIT screen to enter the coordinates of individual points and (2nd) STAT PLOT graph them as "fat dots".

Preferably, download the program (TI-82/83/84, TI-89, or TI-92.) and use the TI link to get them into your calculator. If you do not have the TI link, enter the programs by hand, using the appropriate version below. Replace "->" with the "Store" arrow, "<=" with the "less than or equal" symbol, and ">=" with the "greater than or equal" symbol.

TI-82/83/84 version:

(Thanks to Dennis Dougherty for debugging this.)

Disp "STARTING POINT"
Input "X?",C:C->M
Input "Y?",D:D->N
Input "RISE? ",B
Input "RUN? ",A
While C>=Xmin and C<=Xmax and D>=Ymin and D<=Ymax
Line(C,D,C,D+B)
Line(C,D+B,C+A,D+B)
C+A->C:D+B->D
End
Line(C,D,M,N)

TI-89 version:

()
Prgm

Local usermode
getMode("all")->usermode
setGraph("Axes","ON")
setMode("Split Screen","FULL")
15.8->xmin:15.8->xmax
7.6->ymin:7.6->ymax
1->xscl
1->yscl

 -- subroutines --

Local dostair,clean

Define dostair()=Prgm

 Dialog
  Title "STAIR"
  Text " Starting point"
   Request "x",v
   Request "y",w
  Text " Slope"
   Request "Run",c
   Request "Rise",d
 EndDlog
 expr(v)->x
  x->m
 expr(w)->y
  y->n
 expr(c)->a
 expr(d)->b

 While x>=xmin and x<=xmax and y>=ymin and y<=ymax
  If a=0 and b=0:Exit
  Line x,y,x,y+b
  Line x,y+b,x+a,y+b
  x+a->x:y+b->y
 EndWhile
 Line x,y,m,n

 Pause 

EndPrgm

Define clean()=Prgm
 ClrDraw
 DispG
 1->ch
EndPrgm

 -- main program --

Loop
 PopUp {"Stair","Erase","Quit"},ch
 If ch=1 Then:dostair()
  ElseIf ch=2 Then:clean()
  ElseIf ch=3 Then:setMode(usermode):Exit
 EndIf
EndLoop

EndPrgm

TI-92 version:

()
Prgm

setGraph("Axes","ON")
setMode("SplitScreen","FULL")
-23.8->xmin:23.8->xmax
-10.2->ymin:10.2->ymax
1->xscl
1->yscl

© -- subroutines --

Local dostair,clean

Define dostair()=Prgm

 Dialog
  Title "STAIR"
  Text " Starting point"
   Request "x",v
   Request "y",w
  Text " Slope"
   Request "Run",c
   Request "Rise",d
 EndDlog
 
 expr(v)->x
  x->m
 expr(w)->y
  y->n
 expr(c)->a
 expr(d)->b

 While x>=xmin and x<=xmax and y>=ymin and y<=ymax
  If a=0 and b=0:Exit
  Line x,y,x,y+b
  Line x,y+b,x+a,y+b
  x+a->x:y+b->y
 EndWhile
 Line x,y,m,n

 Pause 

EndPrgm

Define clean()=Prgm
 ClrDraw
 DispG
 1->ch
EndPrgm

© -- main program --

Loop
 PopUp {"Stair","Erase","Quit"},ch
 If ch=1 Then:dostair()
  ElseIf ch=2 Then:clean()
  ElseIf ch=3 Then:Exit
 EndIf
EndLoop

setMode("Split 1 App","Home")
DelVar a,b,m,n,x,y,ch

EndPrgm

Visit Henri Picciotto's Math Education Page. Send me e-mail .