(1) As shown in the figure, take the AC midpoint f, connect BF, and then connect BF ⊥ AC. Take A as the coordinate origin, the straight line passing through A and parallel to FB as the X axis, AC as the Y axis, and AP as the Z axis to establish a spatial rectangular coordinate system, as shown in the figure.

Then a (0 0,0,0), b (3, 1 0), c (0 0,2,0), p (0 0,0,2), e (0, 1, 1).

∴pb=(3, 1,-2),ae=(0, 1, 1)

Let the angle formed by AE and PB be θ, then cosθ=|PB? AE|PB|？ |AE||= 14

That is, the cosine of the angle formed by the straight line AE and PB is 14.