优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知平面向量\( \overrightarrow{a}=(1,1), \overrightarrow{b}=(1,-1)\),则向量\( \dfrac {1}{2} \overrightarrow{a}- \dfrac {3}{2} \overrightarrow{b}=(\)  \()\)
              A.\((-2,-1)\)
              B.\((-1,2)\)
              C.\((-1,0)\)
              D.\((-2,1)\)
            • 2.
              已知平面上三点\(A(2,-4)\),\(B(0,6)\),\(C(-8,10)\),则\( \dfrac {1}{2} \overrightarrow{AC}- \dfrac {1}{4} \overrightarrow{BC}\)的坐标是 ______ .
            • 3.
              \(\triangle ABC\)所在平面上一点\(P\)满足\( \overrightarrow{PA}+ \overrightarrow{PB}+ \overrightarrow{PC}= \overrightarrow{AB}\),则\(\triangle PAB\)的面积与\(\triangle ABC\)的面积比为\((\)  \()\)
              A.\(2\):\(3\)
              B.\(1\):\(3\)
              C.\(1\):\(4\)
              D.\(1\):\(6\)
            • 4.
              已知向量\( \overrightarrow{a}\),\( \overrightarrow{b}\)满足\(| \overrightarrow{a}+ \overrightarrow{b}|=| \overrightarrow{a}- \overrightarrow{b}|=5\),则\(| \overrightarrow{a}|+| \overrightarrow{b}|\)的取值范围是\((\)  \()\)
              A.\([0,5]\)
              B.\([5,5 \sqrt {2}]\)
              C.\([5 \sqrt {2},7]\)
              D.\([5,10]\)
            • 5.
              已知向量\( \overrightarrow{a}\),\( \overrightarrow{b}\)满足条件\(| \overrightarrow{a}|=2\),\(| \overrightarrow{b}|=3\),\( \overrightarrow{a}\)与\( \overrightarrow{b}\)的夹角为\(60^{\circ}\),则\(| \overrightarrow{a}- \overrightarrow{b}|=\) ______ .
            • 6.
              边长为\(8\)的等边\(\triangle ABC\)所在平面内一点\(O\),满足\( \overrightarrow{OA}-2 \overrightarrow{OB}-3 \overrightarrow{OC}= \overrightarrow{0}\),若\(| \overrightarrow{OP}|= \sqrt {19}\),则\(|PA|\)的最大值为\((\)  \()\)
              A.\(6 \sqrt {3}\)
              B.\(2 \sqrt {19}\)
              C.\(3 \sqrt {19}\)
              D.\(4 \sqrt {19}\)
            • 7.
              已知\(\triangle ABC\)满足\( \overrightarrow{AB}^{2}= \overrightarrow{AB}\cdot \overrightarrow{AC}+ \overrightarrow{BA}\cdot \overrightarrow{BC}+ \overrightarrow{CA}\cdot \overrightarrow{CB}\),则\(\triangle ABC\)是\((\)  \()\)
              A.等边三角形
              B.锐角三角形
              C.直角三角形
              D.钝角三角形
            • 8.
              已知向量\( \overrightarrow{α}\),\( \overrightarrow{β}\),\( \overrightarrow{γ}\)满足\(| \overrightarrow{α}|=1\),\(| \overrightarrow{α}- \overrightarrow{β}|=| \overrightarrow{β}|\),\(( \overrightarrow{α}- \overrightarrow{γ})\cdot ( \overrightarrow{β}- \overrightarrow{γ})=0.\)若对每一确定的\( \overrightarrow{β}\),\(| \overrightarrow{γ|}\)的最大值和最小值分别为\(m\),\(n\),则对任意\( \overrightarrow{β}\),\(m-n\)的最小值是\((\)  \()\)
              A.\( \dfrac {1}{2}\)
              B.\( \dfrac {1}{4}\)
              C.\( \dfrac {3}{4}\)
              D.\(1\)
            • 9.
              向量\( \overrightarrow{e_{1}}=(1,2)\),\( \overrightarrow{e_{2}}=(3,4)\),且\(x\),\(y∈R\),\(x \overrightarrow{e_{1}}+y \overrightarrow{e_{2}}=(5,6)\),则\(x-y=(\)  \()\)
              A.\(3\)
              B.\(-3\)
              C.\(1\)
              D.\(-1\)
            • 10.
              已知点\(P\)是\(\triangle ABC\)所在平面内一点,满足\( \overrightarrow{PA}+ \overrightarrow{PB}+ \overrightarrow{PC}= \overrightarrow{0}\),从\(\triangle ABC\)内任取一点\(Q\),则点\(Q\)在\(\triangle PBC\)内部的概率为\((\)  \()\)
              A.\( \dfrac {1}{4}\)​
              B.\( \dfrac {1}{3}\)
              C.\( \dfrac {1}{2}\)
              D.\( \dfrac {2}{3}\)
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