Least Squares Parabola

Dragan

Super Moderator
#2
Hi all

I have been trying to find the values of the coefficients for the least squares parabola:

y = a + bx + cx^2

I have taken partial derivatives wrt a, b, c and now have three equations, but I don't know what to do next...any suggestions? Have you solved this before?

thank you very much!!

I can help with LaTeX in exchange for help thank you very much

Your system of normal equations should look like the following:

\(\Sigma y=an+b\Sigma x+c\Sigma x^{2}\)

\(\Sigma xy=a\Sigma x+b\Sigma x^{2}+c\Sigma x^{3}\)

\(\Sigma x^{2}y=a\Sigma x^{2}+b\Sigma x^{3}+c\Sigma x^{4}\)
 

Dason

Ambassador to the humans
#3
It's a system of three equations with three unknowns (a, b, c). Everything else is taken as a known fixed value. If I told you to solve for a, b, c given the following equations could you do it?

1 = 3a + 4b - 2c
2 = 7a - 13b + 8c
92 = a + b - c