优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知向量\( \overrightarrow{m}=( \sqrt {3}\sin \dfrac {x}{4},1)\),\( \overrightarrow{n}=(\cos \dfrac {x}{4},\cos ^{2} \dfrac {x}{4})\),记\(f(x)= \overrightarrow{m}\cdot \overrightarrow{n}\).
              \((\)Ⅰ\()\)求\(f(x)\)的单调递减区间;
              \((\)Ⅱ\()\)若\(f(a)= \dfrac {3}{2}\),求 \(\cos ( \dfrac {2π}{3}-a)\)的值;
              \((\)Ⅲ\()\)将函数\(y=f(x)\)的图象向右平移\( \dfrac {2π}{3}\)个单位得到\(y=g(x)\)的图象,若函数\(y=g(x)-k\)在\([0, \dfrac {7π}{3}]\)上有零点,求实数\(k\)的取值范围.
            • 2.
              化简:\(\sin 40^{\circ}(\tan 10^{\circ}- \sqrt {3})=\)______.
            • 3.
              设向量\( \overrightarrow{α}=( \sqrt {3}\sin 2x,\cos x+\sin x)\),\( \overrightarrow{β}=(1,\cos x-\sin x)\),其中\(x∈R\),函数\(f(x)= \overrightarrow{α}⋅ \overrightarrow{β}\).
              \((1)\)求\(f(x)\)的最小正周期;
              \((2)\)若\(f(θ)=1\),其中\(0 < θ < \dfrac {π}{2}\),求\(\cos (θ- \dfrac {π}{6})\)的值.
            • 4.

              已知函数\(f(x)=A\sin (ωx+φ)(x∈R,A > 0,ω > 0,0 < φ < \dfrac{π}{2}) \)图象如图,\(P\)是图象的最高点,\(Q\)为图象与\(x\)轴的交点,\(O\)为原点\(.\)且\(\left| \overrightarrow{{OQ}} \right|{=}\dfrac{8}{3}\),\(\left| \overrightarrow{{OP}} \right|{=}\dfrac{\sqrt{13}}{3}\),\(\left| \overrightarrow{{PQ}} \right|{=}\sqrt{5}\).


              \((1)\)求函数\(y=f(x)\)的解析式;

              \((2)\)将函数\(y=f(x)\)图象向右平移\(\dfrac{4}{3}\)个单位后得到函数\(y=g(x)\)的图象,当\(x∈[0,2]\)时,求函数\(h(x)=f(x)·g(x)\)的最小值及其对应的\(x\)的值.

            • 5.
              设向量\( \overrightarrow{m}=(\sin x,-1)\),\( \overrightarrow{n}=( \sqrt {3}\cos x,- \dfrac {1}{2})\),函数\(f(x)=( \overrightarrow{m}+ \overrightarrow{n})⋅ \overrightarrow{m}\).
              \((1)\)求函数\(f(x)\)的单调递增区间;
              \((2)\)当\(x∈(0, \dfrac {π}{2})\)时,求函数\(f(x)\)的值域.
            • 6.

              设\(a=\dfrac{1}{2}\cos 2{}^\circ -\dfrac{\sqrt{3}}{2}\sin 2{}^\circ \),\(b=\dfrac{2\tan 15{}^\circ }{1+{{\tan }^{2}}15{}^\circ }\),\(c=\sqrt{\dfrac{1-\cos 50{}^\circ }{2}}\),则有\((\)   \()\)

              A.\(c < a < b\)
              B.\(a < b < c\)
              C.\(b < c < a\)
              D.\(a < c < b\)
            • 7.

              求函数\(f\left(x\right)=2{\sin }^{2}x+2 \sqrt{3}\sin x·\cos x+1\left(x∈R\right) \)的值域,最小正周期及单调递增区间.

            • 8.

              已知向量\(\overrightarrow{a}=(\sqrt{3}\sin x,\cos x),\ \ \overrightarrow{b}=(\cos x,\cos x)\) ,函数\(f(x)=2\overrightarrow{a}\cdot \overrightarrow{b}-1\)

              \((1)\)求\(f(x)\)的单调递增区间;   

              \((2)\)当\(x\in [\dfrac{\pi }{6},{ }\dfrac{\pi }{{2}}]\)时,若\(f(x)=1,\)求\(x\)的值。

            • 9.

              已知\(\overrightarrow{a}=(\sin x,-\dfrac{1}{2})\),\(\overrightarrow{b}=(\sqrt{3}\cos x+\sin x,1)\),函数\(f(x)=\overrightarrow{a}\cdot \overrightarrow{b}\),\(\triangle ABC\)的内角\(A\),\(B\),\(C\)所对的边长分别为\(a\),\(b\),\(c\).

              \((1)\)若\(f(\dfrac{B+C}{2})=1\),\(a=\sqrt{3}\),\(b=1\),求\(\triangle ABC\)的面积\(S\);

              \((2)\)若\(0 < \alpha < \dfrac{\pi }{4}\),\(f(a)=\dfrac{3}{5}\),求\(\cos 2α\)的值.

            • 10.

              设\({a}=\dfrac{1}{2}\cos {{8}^{0}}-\dfrac{\sqrt{3}}{2}\sin {{8}^{0}},b=\dfrac{2\tan {{13}^{0}}}{1-{{\tan }^{2}}{{13}^{0}}},c=\sqrt{\dfrac{1-\cos {{52}^{0}}}{2}}\),则\(a\),\(b\),\(c\)的大小关系为       \(.\)  

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