This topic is the finale of quadratic function, which I find very difficult. There are many knowledge points about images and properties of quadratic function, undetermined coefficient method, graphic area, Pythagorean theorem, so it is even more difficult to discuss them in categories. The answer is/exercise/math /799755/? The exam, we can discuss it. I'm actually a little dizzy, and I don't quite understand it. I hope you can adopt it.

The two sides OA and OC of the right-angled trapezoid ABCO are on the positive semi-axis of the coordinate axis BC//x, OA=OC=4, and the parabola with the straight line x= 1 as the symmetry axis passes through three points A, B and C. 。

(2) It is known that the analytical formula of the straight line L is y=x+m, and it intersects with the X axis at point G, taking point P on one side of the trapezoid ABCO.

(1) when m=0, as shown in figure 1, point p is the intersection of parabola symmetry axis and BC, and the area of triangle OPH is found;

(2) When m=-3, take the intersection point P as the vertical line between the X axis and the straight line L, and the vertical foot as points E and F. Is there such a point P, and the triangle with the vertices of P, E, F, E and F is an isosceles triangle? If it exists, find the coordinates of point P; If it doesn't exist,