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数学
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△ABC中,角A,B,C所对的边分别为a,b,c,若C=
π
3
,3a=2c=6,则b的值为( )
A.
3
B.
2
C.
6
-1
D. 1+
6
人气:477 ℃ 时间:2019-11-02 02:15:59
解答
∵a=2,c=3,∠C=60°,
∴根据余弦定理得:c
2
=a
2
+b
2
-2ab•cosC
9=4+b
2
-2b,
则b=
1+
6
.
故选D.
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