优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知\(\triangle ABC\)的内角\(A\),\(B\),\(C\)所对的边分别为\(a\),\(b\),\(c\),若\(B=2A\),\(a=1\),\(b= \sqrt {3}\),则\(c=\) ______ .
            • 2.
              在\(\triangle ABC\)中,若\(∠B= \dfrac {π}{4}\),\(b= \sqrt {2}a\),则\(∠C=\) ______ .
            • 3.
              在\(\triangle ABC\)中,\(a\),\(b\),\(c\)分别是角\(A\),\(B\),\(C\)的对边,且满足\( \dfrac {2a-b}{c}= \dfrac {\cos B}{\cos C}\),
              \((1)\)求角\(C\)的大小;
              \((2)\)设函数\(f(x)=2\sin x\cos x\cos C+2\sin ^{2}x\sin C- \dfrac { \sqrt {3}}{2}\),求函数\(f(x)\)在区间\([0, \dfrac {π}{2}]\)上的值域.
            • 4.
              在\(\triangle ABC\)中,角\(A\),\(B\),\(C\)的对边分别是\(a\),\(b\),\(c\),已知\(b=2,c=2 \sqrt {2}\),且\(C= \dfrac {π}{4}\),则\(\triangle ABC\)的面积为\((\)  \()\)
              A.\( \sqrt {3}+1\)
              B.\( \sqrt {3}-1\)
              C.\(4\)
              D.\(2\)
            • 5.
              若在\(\triangle ABC\)中,\( \dfrac {\sin B}{b}= \dfrac {\cos A}{a}= \dfrac {\cos C}{c}\),则\(\triangle ABC\)是 ______ 三角形.
            • 6.
              在\(\triangle ABC\)中,\(a^{2}\tan B=b^{2}\tan A\),则\(\triangle ABC\)是\((\)  \()\)
              A.等腰三角形
              B.直角三角形
              C.等腰三角形
              D.等腰或直角三角形
            • 7.
              在\(\triangle ABC\)中,角\(A\),\(B\),\(C\)所对应的边分别是\(a\),\(b\),\(c\),若\(\sin C+\sin A(\sin B-\cos B)=0\),\(a=2,c= \sqrt {2}\),则\(B=(\)  \()\)
              A.\( \dfrac {π}{12}\)
              B.\( \dfrac {π}{6}\)
              C.\( \dfrac {π}{4}\)
              D.\( \dfrac {π}{3}\)
            • 8.
              在\(\triangle ABC\)中,角\(A\),\(B\),\(C\)的对边分别为\(a\),\(b\),\(c\),已知\(A=2B\).
              \((1)\)求证:\(a^{2}=b(b+c)\);
              \((2)\)若\(\triangle ABC\)的面积为\( \dfrac {1}{4}a^{2}\),求\(B\)的大小.
            • 9.
              \(\triangle ABC\)的三个内角\(A\),\(B\),\(C\)所对的边分别为\(a\),\(b\),\(c\),且满足\( \dfrac {\sin B-\sin A}{\sin B-\sin C}= \dfrac {c}{a+b}\),则\(A=(\)  \()\)
              A.\( \dfrac {π}{6}\)
              B.\( \dfrac {π}{3}\)
              C.\( \dfrac {2π}{3}\)
              D.\( \dfrac {π}{3}\)或\( \dfrac {2π}{3}\)
            • 10.
              已知\(a\),\(b\),\(c\)分别为\(\triangle ABC\)三个内角\(A\),\(B\),\(C\)的对边,且\(a\cos C+ \sqrt {3}a\sin C-b-c=0\).
              \((1)\)求\(A\);
              \((2)\)若\(AD\)为\(BC\)边上的中线,\(\cos B= \dfrac {1}{7}\),\(AD= \dfrac { \sqrt {129}}{2}\),求\(\triangle ABC\)的面积.
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