本題考查向量的數(shù)量積運算。因為
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,所以
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,即
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。
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
在等腰
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中,
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,
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,則
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( )
A.(-3,-1) | B.(-3,1) | C. | D.(3,1) |
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
已知向量
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,向量
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,若
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,則實數(shù)

的值是(�。�
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分12分)在平面直角坐標(biāo)系
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中,已知點
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),
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,其中
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.
(1)若
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,求證:
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;
(2)若
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,求

的值.
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分14分)
已知向量
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向量
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向量
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滿足
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(1)求證:
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(2)若
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與
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共線,求實數(shù)

的值.
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科目:高中數(shù)學(xué)
來源:不詳
題型:填空題
設(shè)向量
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=(2,-1),向量
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與
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共線且
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與
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同向,

的模為
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,則
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=
。
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