It is known that the triangle ABC is an equilateral triangle, EC is perpendicular to the plane ABC, BD is perpendicular to the plane ABC, and EC and DB are on the same side of the plane ABC It is known that the triangle ABC is an equilateral triangle, EC is perpendicular to plane ABC, BD is perpendicular to plane ABC, and EC and DB are on the same side of plane ABC, M is the midpoint of EA, CE = 2bd. It is proved that: (1) plane BDM is perpendicular to plane ECA; (2) plane DEA is perpendicular to plane ECA

It is known that the triangle ABC is an equilateral triangle, EC is perpendicular to the plane ABC, BD is perpendicular to the plane ABC, and EC and DB are on the same side of the plane ABC It is known that the triangle ABC is an equilateral triangle, EC is perpendicular to plane ABC, BD is perpendicular to plane ABC, and EC and DB are on the same side of plane ABC, M is the midpoint of EA, CE = 2bd. It is proved that: (1) plane BDM is perpendicular to plane ECA; (2) plane DEA is perpendicular to plane ECA

AC midpoint n, connecting Mn, BN, Mn is the median line of △ AEC, Mn / / EC, BD ⊥ plane ABC, EC ⊥ plane ABC, Mn ⊥ plane ABC, Mn / / BD, Mn = BD, D, B, N, m are in the same plane, BN ⊥ AC, BN ⊥ Mn, BN ⊥ plane AEC, BN ∈ plane bnmd, plane BDM ⊥ plane ECA.DM//BN , DM ⊥ face AEC, face DEA ⊥ AEC