在△ABC中,角A、B、C的对边分别为a,b,c.角A,B,C成等差数列.
(Ⅰ)求cosB的值;
(Ⅱ)边a,b,c成等比数列,求sinAsinC的值.
考点分析:
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设△ABC的内角A,B,C所对边的长分别为a,b,c,则下列命题正确的是
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④若(a+b)c=2ab,则C>
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.
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已知直线l
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已知函数f(x)=cos
2(
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设△ABC的内角A,B,C,所对的边分别是a,b,c.若(a+b-c)(a+b+c)=ab,则角C=
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在△ABC中,
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,则△ABC一定是( )
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B.直角三角形
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D.等腰直角三角形
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