＝12
|????|－?AD????AE2????1·AE ＝1
2×(2)2－1×2×cos45°＝0. ∴??????D????1M⊥AE.∴D1M⊥AE.
??????∵?????DM·????AB＝(1????????12AE－AD1)·AB ＝1?????????????????2
AE·AB－AD1·AB ＝1
2×2×2×cos45°－1×2×cos60°＝0，??????∴D????1M⊥AB，∴D1M⊥AB.
又AE∩AB＝A，AE、AB?平面ABCE， ∴D1M⊥平面ABCE. ∵D1M?平面D1AE， ∴平面D1AE⊥平面ABCE. 6