优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知\(\cos α=- \dfrac {4}{5}\),\(α\)为第三象限角.
              \((1)\)求\(\sin α\),\(\tan α\)的值; 
              \((2)\)求\(\sin (α+ \dfrac {π}{4})\),\(\tan 2α\)的值.
            • 2.
              \((1)\)已知\(\tan α=-2\),计算:\( \dfrac {3\sin α+2\cos α}{5\cos \alpha -\sin \alpha }\)
              \((2)\)已知\(\sin α= \dfrac {2 \sqrt {5}}{5}\),求\(\tan (α+π)+ \dfrac {\sin ( \dfrac {5π}{2}+α)}{\cos ( \dfrac {5π}{2}-\alpha )}\)的值.
            • 3.
              \((1)\)已知\(\tan β= \dfrac {1}{2}\),求\(\sin ^{2}β-3\sin β\cos β+4\cos ^{2}β\)的值.
              \((2)\)求函数定义域:\(y= \sqrt {-2\cos ^{2}x+3\cos x-1}+\lg (36-x^{2})\).
            • 4.
              已知\(\sin θ+\cos θ= \dfrac {4}{3}\),\(θ∈(0, \dfrac {π}{4})\),则\(\sin θ-\cos θ\)的值为\((\)  \()\)
              A.\( \dfrac { \sqrt {2}}{3}\)
              B.\(- \dfrac { \sqrt {2}}{3}\)
              C.\( \dfrac {1}{3}\)
              D.\(- \dfrac {1}{3}\)
            • 5.
              已知\(\sin α=- \dfrac {2 \sqrt {5}}{5}\),且\(\tan α < 0\)
              \((1)\)求\(\tan α\)的值;
              \((2)\)求\( \dfrac {2\sin (α+π)+\cos (2π-α)}{\cos (\alpha - \dfrac {π}{2})-\sin ( \dfrac {3π}{2}+\alpha )}\)的值.
            • 6.
              已知点\(G\)是\(\triangle ABC\)的重心,且\(AG⊥BG\),\( \dfrac {1}{\tan A}+ \dfrac {1}{\tan B}= \dfrac {λ}{\tan C}\),则实数\(λ\)的值为\((\)  \()\)
              A.\( \dfrac {1}{3}\)
              B.\( \dfrac {1}{2}\)
              C.\(3\)
              D.\(2\)
            • 7.
              已知锐角三角形的两个内角\(A\),\(B\)满足\(\tan A- \dfrac {1}{\sin 2A}=\tan B\),则有\((\)  \()\)
              A.\(\sin 2A-\cos B=0\)
              B.\(\sin 2A+\cos B=0\)
              C.\(\sin 2A+\sin B=0\)
              D.\(\sin 2A-\sin B=0\)
            • 8.
              已知角\(θ\)为第四象限角,且\(\tan θ=- \dfrac {3}{4}\),则\(\sin θ+\cos θ=(\)  \()\)
              A.\( \dfrac {1}{5}\)
              B.\( \dfrac {7}{5}\)
              C.\(- \dfrac {1}{5}\)
              D.\(- \dfrac {7}{5}\)
            • 9.
              已知\(\sin α-\cos α= \sqrt {2}\),\(α∈(0,π)\),则\(\tan α\)的值是\((\)  \()\)
              A.\(-1\)
              B.\(- \dfrac { \sqrt {2}}{2}\)
              C.\( \dfrac { \sqrt {2}}{2}\)
              D.\(1\)
            • 10.
              已知\(α∈(0, \dfrac {π}{2})\),且\(f(a)=\cos α\cdot \sqrt { \dfrac {1-\sin α}{1+\sin \alpha }}+\sin α\cdot \sqrt { \dfrac {1-\cos α}{1+\cos \alpha }}\).
              \((1)\)化简\(f(a)\);  
              \((2)\)若\(f(a)= \dfrac {3}{5}\),求\( \dfrac {\sin α}{1+\cos \alpha }+ \dfrac {\cos α}{1+\sin \alpha }\)的值.
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