# minimum number of points needed to define a unique 2 degree curve

as the title says to find minimum number of points needed to define a unique 2 degree. i did it by thinking that in general equation of 2 degree $Ax^2 + By^2 + 2Gx + 2Fy + 2Hxy + C$ there are 6 variables and there so minimum 6 points are needed to define a 2 degree curve. is my approach correct ? if not please tell how to solve this problem. thanks

• If it is a circle you need only 3 points, so the minimum must be equal or smaller than 3 – user261263 Oct 14 '15 at 16:10