1 AB1‖DC1,AD1‖BC1∴面AB1D1‖面BDC1.OC1∈面BDC1.∴.C1O‖面AB1D1
2,设P为ABB1A1中心.∴CB⊥ABB1A1.∴AB1⊥BC.又AB1⊥A1B.∴AB1⊥面A1BC.AB1⊥A1C
同理.B1D1⊥面A1C1C.B1D1⊥A1C.A1C⊥面AB1D1
已知正方形ABCD—A1B1C1D1,O是底面ABCD对角线的交点.
已知正方形ABCD—A1B1C1D1,O是底面ABCD对角线的交点.
求证1.C1O‖面AB1D1
2.A1C⊥面AB1D1
求证1.C1O‖面AB1D1
2.A1C⊥面AB1D1
数学人气:456 ℃时间:2020-04-07 06:20:57
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