ĐẶT AB A AC B AD C               ,                ,  , GỌI G LÀ TRỌNG TÂM CỦA TAM GIÁC BCD

Câu 17: Cho tứ diện ABCD. Đặt

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AB a AC b AD c

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

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

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

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gọi G là trọng tâm của tam giác BCD.

Trong các đẳng thức sau, đẳng thức nào đúng?

A.

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AG b c d

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  

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B.

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^AG

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¹

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^{b c d}

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^{ }

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C.

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^AG

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^{b c d}

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^{ }

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D.

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^AG

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^{b c d}

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^{ }

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