(1)∵∠ACE=90°,AB⊥BD,ED⊥BD,
∴∠ACB+∠ECD=90°,∠ACB+∠BAC=90°,∠B=∠D=90°,
∴∠BAC=∠ECD,
∴△ABC∽△CDE,
∴
=AB BC
,CD ED
∵tan∠ACB=
=2,AB=4,ED=3,AB BC
∴
=2,即BC=2,CD=6,CD ED
则BD=BC+CD=2+6=8;
(2)∵△ABC∽△CDE,
∴
=AC CE
=AB CD
=4 6
,2 3
则tan∠AEC=
=AC CE
.2 3