20 12 Shenyang senior high school entrance examination mathematics 25 questions 4 detailed explanation.
(1) Bring in a point to find the parameters m, n, (2) Draw a parabola, which can be proved by combining ∠ OEF = 45, (3) Draw and combine) When △EOF is an isosceles triangle, the two waists are equal, and the distance formula between two points can find the coordinates of E, (4) Set the coordinates of the point, and according to the conditional sequence.