优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知\(\sin θ= \dfrac {1}{3}\),\(θ∈( \dfrac {π}{2},π)\),则\(\tan θ=(\)  \()\)
              A.\(-2\)
              B.\(- \sqrt {2}\)
              C.\(- \dfrac { \sqrt {2}}{4}\)
              D.\(- \dfrac { \sqrt {2}}{8}\)
            • 2.
              若\(\cos α=- \dfrac {4}{5}\),且\(α\)为第二象限角,则\(\tan α=(\)  \()\)
              A.\(- \dfrac {4}{3}\)
              B.\(- \dfrac {3}{4}\)
              C.\( \dfrac {4}{3}\)
              D.\( \dfrac {3}{4}\)
            • 3.
              已知\(\tan α=2\).
              \((1)\)求\(\tan (α- \dfrac {π}{4})\)的值;
              \((2)\)求\( \dfrac {\sin 2α}{\sin ^{2}\alpha +\sin \alpha \cos \alpha -\cos 2\alpha -1}\).
            • 4.
              如果\(\cos α= \dfrac {1}{5}\),且\(α\)是第四象限的角,那么\(\cos (α+ \dfrac {π}{2})=\)______.
            • 5.
              若\(α\)为第二象限的角,且\(\tan α=- \dfrac {5}{12}\),则\(\cos α=(\)  \()\)
              A.\( \dfrac {5}{13}\)
              B.\(- \dfrac {5}{13}\)
              C.\( \dfrac {12}{13}\)
              D.\(- \dfrac {12}{13}\)
            • 6.
              若\(θ\)是\(\triangle ABC\)的一个内角,且\(\sin θ\cos θ=- \dfrac {1}{8}\),则\(\cos θ-\sin θ\)的值为\((\)  \()\)
              A.\(- \dfrac { \sqrt {3}}{2}\)
              B.\( \dfrac { \sqrt {3}}{2}\)
              C.\(- \dfrac { \sqrt {5}}{2}\)
              D.\( \dfrac { \sqrt {5}}{2}\)
            • 7.
              若\(\tan α=2\),则\( \dfrac {\sin α-\cos α}{\sin \alpha +\cos \alpha }\)的值为 ______ .
            • 8.
              若\(\sin α < 0\)且\(\tan α > 0\),则\(α\)是\((\)  \()\)
              A.第一象限角
              B.第二象限角
              C.第三象限角
              D.第四象限角
            • 9.
              已知\(\sin α+\cos α=- \dfrac {1}{3}\),则\(\sin 2α=(\)  \()\)
              A.\( \dfrac {1}{2}\)
              B.\(- \dfrac {1}{2}\)
              C.\( \dfrac {8}{9}\)
              D.\(- \dfrac {8}{9}\)
            • 10.
              \((1)\)已知\(\cos b=- \dfrac {3}{5}\),且\(b\)为第二象限角,求\(\sin b\)的值.
              \((2)\)已知\(\tan α=2\),计算\( \dfrac {4\sin α-2\cos α}{5\cos \alpha +3\sin \alpha }\) 的值.
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