# Matlab program help

• MATLAB
Gold Member

## Homework Statement

Write a matlab program to compute f'(0) for f(x)=e^x and h=1;0.1;0.01....1E-9 using the forward and central difference formula. What is the optimal h?

## The Attempt at a Solution

I have no clue how to write programs in matlab, if anyone can help me get started I would REALLY appreciate it.

## Answers and Replies

you mean a matlab script right?

Anyway my advice is to write a function as have h as the input, and f' as the output..
in the function, you will just write the formula as a function of h.
as for which value is optimum, well it's related to how close it is to the real value...

Last edited:
chroot
Staff Emeritus
Science Advisor
Gold Member
Well, for staters, do you know the two expressions for the derivative that are mentioned in the assignment?

In other words, do you know how to express the derivative as each of these two kinds of differences?

- Warren

Gold Member
no, i dont know what the formulas are

chroot
Staff Emeritus
Science Advisor
Gold Member
Then your first step must be looking up the definition of a derivative in your textbook.

- Warren

Gold Member
i know what a derivative is, i dont know how to program in matlab.

$$f'(x)=\lim_{h{\rightarrow}0}\frac{f(x+h)-f(x)}{h}$$

Do you know how to program at all ?
in any language?

It's not the answer, but you may might to read such a page as: http://mathworld.wolfram.com/FiniteDifference.html

btw: regarding the last post -- being a good programmer is not a prerequisite of a question like this  