∵BF is contained in the plane ABFD.

∴ Aircraft Company PEF⊥ Aircraft Company

(2) Let the intersection point P be the PO⊥EF of point O, and it can be known from (1) that the plane PEF⊥ plane ABFD, then the PO⊥ plane ABFD is connected to do∴.

Authors: PF⊥PD, PF⊥BF and BF∨ad.

∴PF⊥AD, PF⊥ Aircraft PDE∴PF⊥PE

Let the side length of square ABCD be 2, then PF= 1, ED= 1, PD=EF=2∴PE=√3.

If PF×PE=EF×PO, then PO=√3/2.

In Rt△POD, sin

The sine value of the angle between DP and ABFD plane is 3/4.