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Thread Subject: Help needed wih simple diff function

Subject: Help needed wih simple diff function

From: A

Date: 29 Apr, 2008 14:23:04

Message: 1 of 1

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Hi to all!

I really need some help with a m-file I'm working on. I know
some math but I'm a total noob with matlab.

I need to write an m-file that does the following operations
to a given function.
-given function = f
-given dot = x
-given spacing = dx

The function that would do all of the operations is named as
fun.

1. The fun function will calculate the derivative of any
given function f in any given dot x.

2. The fun will also calculate the differential of the given
function f in the given dot x, both a estimate and the
accurate value with the given spacing dx.

3. This is tough one. The function fun will calculate the
equation of the tangent for the given function f with the
given dot x.

Here's what I've done so far:

function out = fun(f,x,dx)

out = diff(f,x); %The derivative of the function.

out = (diff(f,x)*dx %The estimated value of the differential.

Problems I have with the m-file:
-How is i possible to get multiple out's from one m-file?
-How can I substitute the x with the given value of the x?

All tips are very welcome. Cheers!

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