用等体积法∵E为DD1的中点∴点D1到平面EAC的距离等于D到平面EAC的距离设D到平面EAC的距离为h取AC中点为O,∵正方体棱长为a∴AC=√2a,OD=√2/2a,DE=a/2∵EA=EC,∴EO⊥AC∴OE=√(DE²+OD²)=√3/2a∴SΔACE=1/2...