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在△ABC中,,記,△ABC的面積為,且滿足.
(1)求的取值范圍;
(2)求函數(shù)的最大值和最小值.
(1)(2)

試題分析:(1)由,得
,∴。
的取值范圍為。              6分
(2)注意到=
=                  8分
,∴。
故當(dāng),即時,;            10分
故當(dāng),即時,。              12分
點評:本題主要涉及到向量的數(shù)量積三角形面積的計算及三角函數(shù)性質(zhì),求最值時要注意自變量角的取值范圍
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