优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知在\(\triangle ABC\)中,\(D\)为边\(BC\)上的点,且\(BD=3DC\),点\(E\)为\(AD\)的中点,\( \overrightarrow{BE}=m \overrightarrow{AB}+n \overrightarrow{AC}\),则\(m+n=\) ______ .
            • 2.
              已知\(D\),\(E\)分别是\(\triangle ABC\)边\(AB\),\(AC\)的中点,\(M\)是线段\(DE\)上的一动点\((\)不包含\(D\),\(E\)两点\()\),且满足\( \overrightarrow{AM}=α \overrightarrow{AB}+β \overrightarrow{AC}\),则\( \dfrac {1}{\alpha }+ \dfrac {2}{\beta }\)的最小值为\((\)  \()\)
              A.\(4 \sqrt {2}\)
              B.\(8\)
              C.\(6-4 \sqrt {2}\)
              D.\(6+4 \sqrt {2}\)
            • 3.
              若直线\(x+ky=0(k\neq 0)\)与函数\(f(x)= \dfrac {(2^{x}-1)(1-2\sin ^{2}x)}{2^{x}+1}\)图象交于不同的两点\(A\),\(B\),且点\(C(9,3)\),若点\(D(m,n)\)满足\( \overrightarrow{DA}+ \overrightarrow{DB}= \overrightarrow{CD}\),则\(m+n(\)  \()\)
              A.\(k\)
              B.\(2\)
              C.\(4\)
              D.\(6\)
            • 4.
              已知\(G\)是\(\triangle ABC\)的重心,过点\(G\)作直线\(MN\)与\(AB\),\(AC\)交于点\(M\),\(N\),且\( \overrightarrow{AM}=x \overrightarrow{AB}\),\( \overrightarrow{AN}=y \overrightarrow{AC}\),\((x,y > 0)\),则\(3x+y\)的最小值是\((\)  \()\)
              A.\( \dfrac {8}{3}\)
              B.\( \dfrac {7}{2}\)
              C.\( \dfrac {5}{2}\)
              D.\( \dfrac {4}{3}+ \dfrac {2}{3} \sqrt {3}\)
            • 5.
              平行四边形\(ABCD\)中,\(AB=3\),\(AD=2\),\(∠BAD=120^{\circ}\),\(P\)是平行四边形\(ABCD\)内一点,且\(AP=1\),如\( \overrightarrow{AP}=x \overrightarrow{AB}+y \overrightarrow{AD}\),则\(3x+2y\)的最大值为\((\)  \()\)
              A.\(1\)
              B.\(2\)
              C.\(3\)
              D.\(4\)
            • 6.
              平行四边形\(ABCD\)中,\(M\)是\(BC\)的中点,若\( \overrightarrow{AC}=λ \overrightarrow{AM}+μ \overrightarrow{BD}\),则\(λ+μ=(\)  \()\)
              A.\( \dfrac {9}{4}\)
              B.\(2\)
              C.\( \dfrac {15}{8}\)
              D.\( \dfrac {5}{3}\)
            • 7.
              已知\(l\)是\(\triangle ABC\)的内心,\(AC=2\),\(BC=3\),\(AB=4\),若\( \overrightarrow{AI}=x \overrightarrow{AB}+y \overrightarrow{AC}\),则\(x+y=\) ______ .
            • 8.
              在正方形\(ABCD\)中,\(M\)、\(N\)分别是\(BC\)、\(CD\)的中点,若\( \overrightarrow{AC}=λ \overrightarrow{AM}+μ \overrightarrow{AN}\),则\(λ+μ=\) ______ .
            • 9.
              已知\(O\)是正方形\(ABCD\)的中心\(.\)若\( \overrightarrow{DO}=λ \overrightarrow{AB}+μ \overrightarrow{AC}\),其中\(λ\),\(μ∈R\),则\( \dfrac {λ}{\mu }=(\)  \()\)
              A.\(- \dfrac {1}{2}\)
              B.\(-2\)
              C.\(- \sqrt {2}\)
              D.\( \sqrt {2}\)
            • 10.
              已知\(O\)为\(\triangle ABC\)内一点,且有\( \overrightarrow{OA}+2 \overrightarrow{OB}+3 \overrightarrow{OC}= \overrightarrow{0}\),记\(\triangle ABC\),\(\triangle BCO\),\(\triangle ACO\)的面积分别为\(S_{1}\),\(S_{2}\),\(S_{3}\),则\(S_{1}\):\(S_{2}\):\(S_{3}\)等于\((\)  \()\)
              A.\(3\):\(2\):\(1\)
              B.\(3\):\(1\):\(2\)
              C.\(6\):\(1\):\(2\)
              D.\(6\):\(2\):\(1\)
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