Question

数学空间几何证明题 ,

Answer 1

1.∵BD⊥AA1,BD⊥AC

AA1∩AC=面AA1C1C

∴BD⊥面AA1C1C

又BD∈面A1BD

∴面A1BD⊥面AA1C1C

2.∵O是BD中点,M是A1B中点

∴MO是△A1BD的中位线

∴MO∥A1D

又A1D∥面BCC1B1

∴MO∥面BCC1B1