优优班--学霸训练营 > 知识点挑题
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            • 1.

              已知向量\(a=(-2,1)\),\(b=(-1,3)\),则

              A.\(a⊥(a-b)\)
              B.\(a/\!/(a-b)\)
              C.\(a/\!/b\)
              D.\(a⊥b\)
            • 2.

              已知平面向量\(\overrightarrow{a}=(1,2) \overrightarrow{b}=(-3,2) \),若\(k \overrightarrow{a}+ \overrightarrow{b} \)与\(\overrightarrow{a}-3 \overrightarrow{b} \)垂直,则实数\(k\)值为

              A.\(-\dfrac{1}{3} \)
              B.\(\dfrac{11}{9} \)
              C.\(11\)
              D.\(19\)
            • 3.

              向量\(\overrightarrow{a}=(1,x+1),\overrightarrow{b}=(1-x,2),\overrightarrow{a}\bot \overrightarrow{b},\)则\(\left( \overrightarrow{a}+\overrightarrow{b} \right)\cdot \left( \overrightarrow{a}-\overrightarrow{b} \right)=\)______.

            • 4.

              已知向量\(\overrightarrow{a}{=}(1{,}m){,}\overrightarrow{b}{=}(3{,-}2)\),且\((\overrightarrow{a}{+}\overrightarrow{b}){⊥}\overrightarrow{b}\),则\(m{=}({  })\)

              A.\({-}8\)
              B.\({-}6\)
              C.\(8\)
              D.\(6\)
            • 5.

              从集合\(\{2,3,4,5\}\)中随机抽取一个数\(a\),从集合\(\{1,3,5\}\)中随机抽取一个数\(b\),则向量\(m=(a,b)\)与向量\(n=(1,-1)\)垂直的概率为________.

            • 6.

              已知平面向量\(a=\left(1,2\right) \),\(b=\left(-3,2\right) \),若\(ka+b\)与\(a\)垂直,则实数\(k\)值为\((\)   \()\)

              A.\(-\dfrac{1}{5}\)
              B.\(\dfrac{11}{9}\)
              C.\(11\)
              D.\(19\)
            • 7.

              已知向量\(a\),\(b\),其中\(a=(1,\sqrt{3})\),且\(a⊥(a-3b)\),则\(b\)在\(a\)上的投影为\((\)    \()\)

              A.\(\dfrac{4}{3}\)
              B.\(-\dfrac{4}{3}\)
              C.\(\dfrac{2}{3}\)
              D.\(-\dfrac{2}{3}\)
            • 8.

              已知平面向量\(\overrightarrow{a}\),\(\overrightarrow{b}\)是非零向量,\(|\overrightarrow{a}|=2\),\(\overrightarrow{a}\bot \left( \overrightarrow{a}+2\overrightarrow{b} \right)\),则向量\(\overrightarrow{b}\)在向量\(\overrightarrow{a}\)方向上的投影为\((\)    \()\)

              A.\(1\)
              B.\(-1\)
              C.\(2\)
              D.\(-2\)
            • 9.

              已知\(\overrightarrow{AB}\)与\(\overrightarrow{AC}\)的夹角为\(90^{\circ}\),\(\overrightarrow{|AB|}=2\),\(\overrightarrow{AC}=1\),\(\overrightarrow{AM}=\lambda \overrightarrow{AB}+\mu \overrightarrow{AC}(λ,μ∈R)\),且\(\overrightarrow{AM}\cdot \overrightarrow{BC}=0\),则\(\dfrac{\lambda }{\mu }\)的值为________.

            • 10. 已知平面上三个向量\(\overrightarrow{a}{,}\overrightarrow{b}{,}\overrightarrow{c}\),其中\(\overrightarrow{a}{=}(1{,}2)\).
              \((1)\)若\({|}\overrightarrow{c}{|=}3\sqrt{5}\),且\(\overrightarrow{a}{/\!/}\overrightarrow{c}\),求\(\overrightarrow{c}\)的坐标;
              \((2)\)若\({|}\overrightarrow{b}{|=}3\sqrt{5}\),且\((4\overrightarrow{a}{-}\overrightarrow{b}){⊥}(2\overrightarrow{a}{+}\overrightarrow{b})\),求\(\overrightarrow{a}\)与\(\overrightarrow{b}\)夹角\(\theta\)的余弦值.
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