题目
题型:不详难度:来源:
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(1)
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(2)|3
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(3)3
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答案
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1 |
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(2)|3
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3 |
(3)∵(3
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则cosθ=
(3
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|3
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9 | ||
3
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2 |
π |
6 |
核心考点
试题【已知向量a,b满足|a|=2,|b|=3,a与b的夹角为120°.求(1)a•b; (2)|3a+b|; (3)3a+b与a的夹角.】;主要考察你对平面向量模和夹角的坐标表示等知识点的理解。[详细]
举一反三
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A.
| B.
| C.
| D.
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(1)求向量
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(2)求向量
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3 |
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(1)当x=
π |
3 |
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(2)若x∈[
π |
3 |
π |
2 |
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①向量
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A.1个 | B.2个 | C.3个 | D.4个 |