What functions are best for approximating the Least Square Method?

[aldrinkleys]

Which families of functions should I use to approximate it?

I tried f(x) = a + bx + cx^2 + dx^3 + ex^4 + fx^5 + gx^6

a,b,c,d,e,f,g $$\in$$ R

And I got this:

but that curve ignores the hole between 50 and 80.
and this is important for me and f(x) is too long...



Can anyone help me?

 

[edgepflow]

That fit is probably optimal if you want to fit all the data at the same time. You could break the data into two fits for better accuracy, however.

 

[aldrinkleys]

ah, I solved my problem =)I used Harmonic analysis