共50条信息
已知\(\overrightarrow{a}{=}\left( {-}2{,}1{,}3 \right)\),\(\overrightarrow{b}{=}\left( {-}1{,}2{,}1 \right)\),若\(\overrightarrow{a}{⊥}\left( \overrightarrow{a}{-}\lambda\overrightarrow{b} \right)\),则实数\(\lambda\) 的值为 \((\) \()\)
设向量\(a=(3,5,-4)\),\(b=(2,1,8)\).
\((1)\)计算\(2a+3b\),\(3a-2b\),\(a·b;\)
\((2)\)当\(λa+μb\)与\(z\)轴垂直时,求\(λ\),\(μ\)的关系式.
在正方体中\(ABCD-A_{1}B_{1}C_{1}D_{1}\),若\(G\)点是\(\triangle BA_{1}D\)的重心,且\(\overrightarrow{AG}=x\overrightarrow{AD}+y\overrightarrow{AB}+z\overrightarrow{C{{C}_{1}}}\),则\(x+y+z\)的值为
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