"Is there a point on the parabola that makes its distance to a fixed straight line equal to a fixed constant?" Firstly, with the help of the analytical formula of parabola, the coordinates of the moving point are expressed by a letter, and then the equation is established by using the distance formula from the point to the straight line. The abscissa of the moving point can be obtained by solving this equation, and then the ordinate of the moving point on the parabola can be obtained by using the analytical formula of the parabola.

Precautions:

Simply put, a function with the shape of "y=ax2+bx+c(a≠0)" is a quadratic function, but junior high school students still have great problems in understanding the simple definition in the process of doing the problem.

From the basic form of quadratic function to the learning process of function image, it is difficult for junior high school students to understand the function of image, and they will not use the intuition of image to solve problems in the process of doing problems, and they cannot quickly grasp some basic information of quadratic function according to the image of quadratic function.