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在△ABC中,,记,△ABC的面积为,且满足.
(1)求的取值范围;
(2)求函数的最大值和最小值.
(1)(2)

试题分析:(1)由,得
,∴
的取值范围为。              6分
(2)注意到=
=                  8分
,∴
故当,即时,;            10分
故当,即时,。              12分
点评:本题主要涉及到向量的数量积三角形面积的计算及三角函数性质,求最值时要注意自变量角的取值范围
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