The analytical formula is polynomial, and the analytical formula of quadratic function is y = a * x 2+b * x+c a, where b and c are undetermined coefficients, and A≠0.

The two formulas are y = a (x-x 1) (x-x2) a and x 1, where x2 is the undetermined coefficient and A≠0.

It can be seen from the two formulas that the intersection of the function and the Y axis, or the two solutions of Y=0, are X 1, X2.

The vertex is y = a (x-x 1) 2+b a, x 1, where b is the coefficient to be determined, and A≠0.

It can be seen directly from the vertex that the vertex is (X 1, b).

These three formulas can be converted to each other.