题目
题型：不详难度：来源：
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①向量
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答案
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且向量
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②2|
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而由|
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故②正确．
③|2
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等价于 4|
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而 2|
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④|2
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等价于 4|
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故答案为 3．
核心考点
试题【若非零不共线向量a、.b满足|a-.b|=|.b|，则下列结论正确的个数是______．①向量a、.b的夹角恒为锐角； ②2|.b|2＞a•.b； ③|2.】；主要考察你对平面向量数量积的意义等知识点的理解。[详细]
举一反三
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题型：
|sinθ，如果|
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•
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×
|=______．
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