Finite Differences

• May 28th 2011, 04:21 PM
masoug
Finite Differences
Hi,
I am in an Algebra II course where we talk about function fitting with polynomials. We use a method called finite differences to find the degree polynomial that fits the given data (x and y values).

What makes finite differences tick? Why does it work?

Thanks!

-Masoug
• May 28th 2011, 10:06 PM
CaptainBlack
Quote:

Originally Posted by masoug
Hi,
I am in an Algebra II course where we talk about function fitting with polynomials. We use a method called finite differences to find the degree polynomial that fits the given data (x and y values).

What makes finite differences tick? Why does it work?

Thanks!

-Masoug

What makes it work is that the differences of a polynomial of degree n are the values of a polynomial of degree n-1, so if you keep taking the differences of differences you get polynomials of decreasing degree, eventually arriving at a polynomial of degree 0 which is a constant. The number of differences you need to take to arrive at a constant is the degree of the original polynomial.

CB