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如图,已知平行六面体ABCD—A1B1C1D1的底面?ABCD是菱形,且∠C1CB=∠C1CD=∠BCD.
(1)求证: C1C⊥BD
(2)当的值为多少时,能使A1C⊥平面C1BD?请给出证明.
(1)求证:CC1⊥BD;
(2)当的值为多少时,能使A1C⊥平面C1BD?并加以证明.