The determined functional relationships are: undetermined coefficient method.

There are three common forms of analytic functions:

1) general formula: y = ax 2+bx+c (a ≠ 0)

2) Vertex type: y = a (x-h) 2+k (a ≠ 0),

Where the vertex is (h, k)

3) Zero formula: y=a(x-x 1)(x-x2)(a≠0),

Where y=0, and the root of the equation is x 1, x2.

2. When using the knowledge of quadratic function to solve simple practical problems, pay more attention to the combination of function images and numbers and shapes.

Quadratic function (quadratic

The basic expression of the function is y=ax? +bx+c(a≠0). The highest degree of a quadratic function must be quadratic.

The image of a quadratic function is a parabola, and its symmetry axis is parallel or coincident with the Y axis.

Quadratic function expression y=ax? The definition of +bx+c (and a≠0) is quadratic polynomial (or monomial).

If the value of y is equal to zero, a quadratic equation can be obtained. The solution of this equation is called the root of the equation or the zero of the function.