Find coefficient for the best second-order polynomial that fits my data, using least-square fitting

I want to fit my data x= [1,06e-06 1,33e-05 6,23e-05 0,00017 0,00047 0,00100] with a generic second order polynomial y= a*x^2 + b*x + c, using least-square fitting.

I need the coefficient "a" of the polynomial that allows me to have the best fitting with my data.

[Andrei Bobrov]

Where data of y?

[Torsten]

If you have no y-data, what do you want to fit ?

Answer 1

[Bjorn Gustavsson]

Try:

help polyfit

HTH