题目内容
【题目】(本小题满分12分)
在中,内角
对边的边长分别是
,已知
,
.
(Ⅰ)若的面积等于
,求
;
(Ⅱ)若,求
的面积.
【答案】(Ⅰ),
,(Ⅱ)
【解析】
(Ⅰ)由余弦定理及已知条件得,,
又因为的面积等于
,所以
,得
.··········································4分
联立方程组解得
,
.··················································6分
(Ⅱ)由题意得,
即,······························································8分
当时,
,
,
,
,
当时,得
,由正弦定理得
,
联立方程组解得
,
.
所以的面积
.······················································12分
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