1? In triangle ABC, the angle BAC = 90 AD is the height on the side of BC, and E is the moving point on the side of BC, which is different from B? C coincidence, EF vertical AB, EC vertical AC.

(1) proves that EG/AD=CG/CD.

(2) connect FD and DG. Please judge whether FD and DG are vertical.

(3) When AB=AC, is the triangle FDG an isosceles triangle?

2? In triangle ABC, the angle ACB = 90° CD is the height on the side of AB, de is perpendicular to AC, and the extension line of the middle line AG of triangle ADE intersects BC and F.

(1) Prove that f is the midpoint of BC.

(2) If CF=FG, verify that FG=( 1/3)AF.

(3) Under the condition of (2), if AC=6 times the root number 2, find the length of DE.