Parabolic regression problem

how do you find a b and c in parabolic regression? like in this expression: y= -0.20x^2 + 1.94x + 2.78, how do you get 0.20 1.94 and 2.78??

Answer 1

[bym]

A = [ones(size(x)), x, x.^2];
abc = A\y;

[Dwyane Wade]

do you know how to get it in real linear algebra? I mean manually? Without using matlab. I kinda need to know how to...

[Jan]

@Francis: The method to do this manually is exactly the same as proecsm's solution. You have top solve the same system of equations, but manually.

[Dwyane Wade]

what does ones and size mean then?

[Jan]

@Francis: Please read the Getting Started chapters in the documentation for such basic questions. "help size" and "help ones" are helpful also, as for all other MATLAB commands.