(20 15, Hubei, 20, 13) In the nine chapters of arithmetic, a quadrilateral with a rectangular bottom and a side perpendicular to the bottom is called Ma Yang, and a tetrahedron with four right triangles is called turtle. As shown in the figure, in Mayang P-ABCD, side PD⊥ bottom ABCD, PD=CD, and point E is the midpoint of PC, connecting de, BD and BE.
(1) Proof: DE⊥ Plane PBC. Try to judge whether the tetrahedron EBCD is a turtle. If yes, write the right angle of each face (only write the conclusion); If not, please explain the reasons;
(2) Remember that the volume of Mayang P-ABCD is V 1, and the volume of tetrahedral EBCD is V2, and find the value of V 1/V2.