优优班--学霸训练营 > 知识点挑题
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            • 1.

              已知向量\(a=\left(2, \dfrac{x}{2},x\right),b=\left(x,1,2\right) \),其中\(x > 0 \),若\(a/\!/b \),则\(x=\)          

            • 2.

              已知两个向量\(\overrightarrow{a}=(2,-1,3)\),\(\overrightarrow{b}=(4,m,n)\),且\(\overrightarrow{a}\parallel \overrightarrow{b}\),则\(m+n\)的值为\((\)    \()\)

              A.\(1\)
              B.\(2\)
              C.\(4\)
              D.\(8\)
            • 3.
              已知\( \overrightarrow{a}=(1,2,-2)\),则与\( \overrightarrow{a}\)共线的单位向量坐标为 ______ .
            • 4.
              已知\( \overrightarrow{a}=(1,0,2)\),\( \overrightarrow{b}=(-1,1,0)\),\( \overrightarrow{c}=(-1,y,2)\),若\( \overrightarrow{a}\),\( \overrightarrow{b}\),\( \overrightarrow{c}\)三向量共面,则实数\(y\)的值为\((\)  \()\)
              A.\(-2\)
              B.\(-1\)
              C.\(0\)
              D.\(2\)
            • 5.

              与向量\( \overset{⇀}{a} =(1,-3,2)\)平行的一个向量的坐标是\((\)  \()\)

              A.\(\left( \dfrac{1}{3},1,1\right) \)
              B.\((-1,-3,2)\)
              C.\((\) \( \sqrt{2} \) ,\(-3\),\(-2 \sqrt{2} )\)
              D.\((- \dfrac{1}{2} \) , \( \dfrac{3}{2} \) ,\(-1)\)
            • 6.

              已知向量\(a=(3,-1,2),b=(x,y,-4)\),且\(a/\!/b\),则\(x+y=(\) \()\)

              A.\(88\)
              B.\(4\)
              C.\(-4\)
              D.\(-8\)
            • 7. 已知点\(A(3,4,0)\)和向量\( \overrightarrow{a}=(1,-2,1)\),点\(B(0,m,n)\)在\(yOz\)平面上,使向量\( \overrightarrow{AB}/\!/ \overrightarrow{a}\),则点\(B\)的坐标为\((\)  \()\)
              A.\((0,-10,3)\)
              B.\((0,10,-3)\)
              C.\((0,-2,3)\)
              D.\((0,2,-3)\)
            • 8. 已知\( \overrightarrow{a}=(λ+1,0,2λ), \overrightarrow{b}=(6,0,2), \overrightarrow{a}/\!/ \overrightarrow{b} \),则\(λ \)的值为(    )
              A.\(\dfrac{1}{5}\)
              B.\(5\)
              C.\(-\dfrac{1}{5}\)
              D.\(-5\)
            • 9.

              与向量\((-3,-4,5)\)共线的单位向量是(    )。


              A. \(\left( \dfrac{3 \sqrt{2}}{10}, \dfrac{2 \sqrt{2}}{5},- \dfrac{ \sqrt{2}}{2}\right)和\left(- \dfrac{3 \sqrt{2}}{10},- \dfrac{2 \sqrt{2}}{5}, \dfrac{ \sqrt{2}}{2}\right) \)
              B.\((\dfrac{3\sqrt{2}}{10},\dfrac{2\sqrt{2}}{5},-\dfrac{\sqrt{2}}{2})\)
              C. \(\left( \dfrac{3 \sqrt{2}}{10}, \dfrac{2 \sqrt{2}}{5}, \dfrac{ \sqrt{2}}{2}\right)和\left(- \dfrac{3 \sqrt{2}}{10},- \dfrac{2 \sqrt{2}}{5},- \dfrac{ \sqrt{2}}{2}\right) \)
              D.\((-\dfrac{3\sqrt{2}}{10},-\dfrac{2\sqrt{2}}{5},\dfrac{\sqrt{2}}{2})\)
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