Difference Quotient - TI 89 or TI 92

Introduction
This program estimates the value of a derivative at a point using the difference quotient $f^\prime(A)\approx{f(A+H)-f(A)\over H}$

If you have not used one of the programs posted on this website before, you should read through the information in the Intro to Programming section first.

If you have a TI Connectivity Cable, you can download the program main.diffq.89p

The Program

:diffq( ) {This will already appear if you named the program diffq}

:Prgm {This will already appear}

:ClrIO {ClrIO is in the CATALOG menu}

:Lbl p {Lbl is in the CATALOG menu}

:Local a,h {Local is in the F4 menu}

:Input "a=", a {Input is in the F3 menu} { " is on the 1 button}
:Input "h=", h

:(y1(a+h) - y1(a))/h $\to$ d {y1 is the Y button followed by a 1} { $\to$ is STO}

:Disp "estimate", d {Disp is in F3 menu}

:Goto p {Goto is in CATALOG menu}

:EndPrgm {This will already appear}

Running the Program

You will need to enter a function f(x) into y1 before running the program. To test the program try the following:

f(x) = x³, a=2, h=0.01.

The answer should be 12.0601

:diffq( )	{This will already appear if you named the program diffq}
:Prgm	{This will already appear}
:ClrIO	{ClrIO is in the CATALOG menu}
:Lbl p	{Lbl is in the CATALOG menu}
:Local a,h	{Local is in the F4 menu}
:Input "a=", a	{Input is in the F3 menu} { " is on the 1 button}
:Input "h=", h
:(y1(a+h) - y1(a))/h $\to$ d	{y1 is the Y button followed by a 1} { $\to$ is STO}
:Disp "estimate", d	{Disp is in F3 menu}
:Goto p	{Goto is in CATALOG menu}
:EndPrgm	{This will already appear}