Difference Quotient - HP 48

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.

The Program

<<"A" ":A:" INPUT

OBJ 'X' STO

"H" ":H:" INPUT

OBJ 'H' STO

FUNC EVAL 'B' STO

X H + 'X' STO

FUNC EVAL 'C' STO

C B - H / 'D' STO

D "ESTIMATE" TAG

{A B C D H X} PURGE >>

ENTER 'DQ' STO {This stores the program under variable name DQ}

Running the Program

You will need to enter a function f(x) into a variable called FUNC before running the program. Follow the instructions in

<<"A" ":A:" INPUT
OBJ 'X' STO
"H" ":H:" INPUT
OBJ 'H' STO
FUNC EVAL 'B' STO
X H + 'X' STO
FUNC EVAL 'C' STO
C B - H / 'D' STO
D "ESTIMATE" TAG
{A B C D H X} PURGE >>

ENTER 'DQ' STO	{This stores the program under variable name DQ}