设向量
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,
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,
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,函数
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.
(1)求函数

的最小正周期;
(2)在锐角
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中,角
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、
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、
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所对的边分别为
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、
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、
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,
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,

,

,求

的值.
(1)

;(2)3.
试题分析:(1)根据已知条件,求
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,在根据两角和的正弦公式、二倍角公式把

化为
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的形式,由公式
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求得函数的最小正周期;(2)由(1)中
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结合
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求得
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的值,根据

求得

的值,因为

,则有
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求

,最后根据正弦定理求

.
试题解析:(1)
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
4分
所以,函数

的

6分
(2)


,



12分
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
在

处取得最大值,且

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
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
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
,

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
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
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
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
.

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
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
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
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已知向量

.
(1)若

,且

,求角

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(2)若

,且

,求

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