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已知△ABC中,=,=,•<0,S△ABC=,||=3,||=5,则与的夹角为(...
已知△ABC中,
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=
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,
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=
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,
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•
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<0,S
△ABC=
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,|
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|=3,|
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|=5,则
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与
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的夹角为( )
A.30°
B.60°
C.120°
D.150°
考点分析:
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