(2) Vertex: The vertex of the parabola is known as (h, k), and the analytical formula is (a, h, k are all constants, a≠0).

(3) Intersection point: it is known that the parabola intersects the X axis at point A (0)B (0), and the analytical formula is y=a(x- )(x- )(a≠0).

(1) Given three points on a parabola, it can be set as a general formula.

(2) The vertex, symmetry axis or extreme value of a parabola is known and can be set as the vertex.

(3) Given two intersections of parabola and X axis, they can be set as intersections or general formulas.

(1) If the image of quadratic function y=ax2 passes through point P(2 16), then the analytic expression of quadratic function is _ _ _ _ _ _ _.

(2) If the vertex of parabola y=ax2+bx+c is A(2 1) and passes through point B (1, 0), then the resolution function of parabola is _ _ _ _ _.

(3) If the image of a parabola with quadratic coefficient of-1 is as shown in the figure, the resolution function of the parabola is _ _ _ _ _ _ _ _.

1. Ask the students if they know the three types of quadratic resolution function, and then start to introduce the analytical formulas in turn, write down the analytical formulas and definitions of each type, and then start to talk about the general formula in detail.

(1) Ask what the quadratic term coefficient, linear term coefficient and constant term in the general formula are, and explain what they are called quadratic term, linear term and constant term respectively.

(2) Input vertices. Draw a picture, mark the vertices, and guide the students to find that the value of H in the vertices is the value of the axis of symmetry X, and the value of K is the extreme value. Introduce what an opening is and why its directionality is related to A; This paper introduces the use of collocation method from general formula to vertex and deduces it in detail. According to the deduction result y = a(x+)+ and the comparison y=a(x-h) +k, students can understand that the symmetry axis is x=- =-h and the extreme value is y=k=. The point is the point, so they must recite it.

(3) Enter the intersection point. Explain two common test questions: ① find the analytical formula of known intersection; ② Find the intersection point from the known analytical formula. Finding the analytical formula is to use the intersection point, and finding the intersection point is to connect the root formulas of the quadratic equation of one variable that we have learned before. X=

3. Summarize three common examination methods, and then enter the example link to deepen your impression by doing questions and explaining.

Considering the acceptance of students, don't talk about three knowledge points in one breath and introduce them too much. But to introduce a point and make an example right away. You can't put all the knowledge points together, all the examples together.

Well-prepared and rich in content, but the teaching rhythm is not well grasped.

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