Set the standard form y of parabolic equation? =2px, put it into point (2 2,2), and you get 4 = 2p×2, so p= 1, and the equation is y? =2x

A and b are perpendicular to the line l, and the vertical feet are A 1 and B 1.

Defined by parabola, AF=AA 1, BF=BB 1,

So AB=AF+BF=AA 1+BB 1,

So the distance from the midpoint of AB to the straight line L is (the midpoint of the right trapezoid) (AA 1+BB 1)/2=AB/2,

It can be concluded that the circle with AB as the straight line is just tangent to L.

Say you are from Guigang. . This test paper is too familiar to me.