Deriving input-output relationship

1. Jul 11, 2007

jayki

hi frenz

i want to how to derive mathematical relation between dependent(output) and independent(input) variables when i know the relation between them at few samples.
cud someone help me out?

2. Jul 11, 2007

olgranpappy

do you know anything about the functional form? even roughly how it should look? if not then there is no way to extrapolate from a few points to every point.

3. Jul 11, 2007

jayki

as i told , i know the relation between them at few samples. but i want to generalise as a mathematical relation between them

4. Jul 11, 2007

robphy

As olgranpappy says, you can't in general... without at least having a guess to the general form. Given a finite number of samples, you can fit it to a polynomial of sufficiently high degree. However, that polynomial is probably not what you are looking for.

http://en.wikipedia.org/wiki/Curve_fitting
In addition, note the diagrams in
http://slack.net/~ant/bl-synth/3.nyquist.html

5. Jul 12, 2007

jayki

thanks for ur response dear frenz............but let me clear my question again. I have a vector(x) and a vector(y) with the value of x at few points and corresponding value of y. I want to generalize the relation between them with that given samples.