Texas Instruments TI-83 Manual page 23

Program SEC
This program first draws a graph of the function y = f (x) and a tangent line at an inputed point. The
program then graphs a secant line and successive secant lines for values of h approaching zero. One then
sees in the viewing rectangle the secant lines approaching the tangent line.
:ClrDraw
:Disp "X"
:Input X
:Disp "N"
:Input N
:X → A
:Y → B
1
:Xmax X → W
:NDeriv(Y , X, X) → M
1
:Xmax→ C
:B + W M → D
:Line(A,B,C,D)
:DispGraph
:Pause
:1 → H
:1 → J
:Lbl 1
:A + HW → X
:Y → D
1
:(D B)/(HW ) → M
:B + W M → D
:Line(A,B,C,D)
:Pause
:.7H → H
:J + 1 → J
:If J < N + .5
:Goto 1
Programs. The programs for the TI-82 are the same as for the TI-83, but are included here for completeness.
2nd DRAW 1 ENTER
PGRM £ 3 ALPHA " X,T,θ ALPHA " ENTER
PGRM £ 1 X,T,θ ENTER
PGRM £ 3 ALPHA " N ALPHA " ENTER
PGRM £ 1 N ENTER
X,T,θ STO£ A ENTER
2nd Y-VARS 1 1 STO£ B ENTER
VARS 1 2 X,T,θ STO£ W ENTER
MATH 8 2nd Y-VARS 1 1 ,
STO£ M ENTER
VARS 1 2 STO£ C ENTER
B + W M STO£ D ENTER
2nd DRAW 2 A ,
PGRM £ 4 ENTER
PRGM 8 ENTER
1 STO£ H ENTER
1 STO£ J ENTER
PRGM 9 1 ENTER
A + H W STO£ X,T,θ ENTER
2nd Y-VARS 1 1 STO£ D ENTER
( D B ) ÷ ( H W ) STO£ M ENTER
B + W M STO£ D ENTER
2nd DRAW 2 A ,
PRGM 8 ENTER
. 7 H STO£ H
J + 1 STO£ J ENTER
PRGM 1 J 2nd MATH 5 N + .
PRGM 0 1 ENTER
52
,
X,T,θ
B , C ,
D ) ENTER
B , C ,
D ) ENTER
5 ENTER
X,T,θ )