配套习题- 余弦定理的证明 -【青果学院】

1/3单选题

难度：

1.在△ABC中，b=4，c=7，A=60°，则

的值是（）

A	6
B
C
D

正确答案：Qg==

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

2/3单选题

难度：

2.在△ABC中，AB=5，AC=3，BC=7，则∠BAC=（）

A
B
C
D

正确答案：QQ==

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

3/3单选题

难度：

3.在△ABC中，

，则A=（）

A	60°
B	45°
C	120°
D	30°

正确答案：Qw==

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