共50条信息
在\(\triangle ABC\)中,\(2a\cos A+b\cos C+c\cos B=0\),则角\(A\)的大小为( )
若\(\cos (\dfrac{\pi }{8}-\alpha )=\dfrac{1}{6}\),则\(\cos (\dfrac{3\pi }{4}+2\alpha )\)的值为 \((\) \()\)
在三角形\(ABC\)中,若\(A\)为钝角,则\(\tan B\tan C\)的值为( )
函数\(y=3\tan (2x+\pi )\)是\((\) \()\)
若\(\cos \left( \dfrac{\pi }{8}-\alpha \right)=\dfrac{1}{6}\),则\(\cos \left( \dfrac{3\pi }{4}+2\alpha \right)=\)( )
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