共50条信息
如图,在长方体\(ABCD-A\)\(1\)\(B\)\(1\)\(C\)\(1\)\(D\)\(1\)中,\(O\)为\(AC\)的中点,设\(E\)是棱\(DD_{1}\)上的点,且\(\overrightarrow{DE}= \dfrac{2}{3}\overrightarrow{DD_{1}}\),若\(\overrightarrow{EO}=x\overrightarrow{AB}+y\overrightarrow{AD}+z\overrightarrow{AA_{1}}\),试求\(x\),\(y\),\(z\)的值.
已知向量\(a=(0,-1,1)\),\(b=(4,1,0)\),\(|λa+b|= \sqrt{29}\)且\(λ > 0\),则实数\(λ=\)________.
已知三棱锥\(O-ABC\),点\(M\),\(N\)分别为\(AB\),\(OC\)的中点,且\(\overrightarrow{OA}=a\),\(\overrightarrow{OB}=b\),\(\overrightarrow{OC}=c\),用\(a\),\(b\),\(c\)表示\(\overrightarrow{MN}\),则\(\overrightarrow{MN}\)等于\((\) \()\)
在平行六面体\(ABCD—A_{1}B_{1}C_{1}D_{1}\)中,\(M\)为\(AC\)与\(BD\)的交点,若\(\overrightarrow{{{A}_{1}}{{B}_{1}}}=a\),\(\overrightarrow{{{A}_{1}}{{D}_{1}}}=b\),\(\overrightarrow{{{A}_{1}}A}=c\),则下列向量中与\(\overrightarrow{{{B}_{1}}M}\)相等的向量是
设有四边形\(ABCD\),\(O\)为空间任意一点,且\(\overrightarrow{AO}+\overrightarrow{OB}=\overrightarrow{DO}+\overrightarrow{OC}\),则四边形\(ABCD\)是( )
设 \(OABC\) 是四面体,\({G}_{1} \) 是\(∆ABC \) 的重心,\(G\) 是\(O{G}_{1} \) 上一点,且\(OG=3G{G}_{1} \),若\( \overrightarrow{OG}=x \overrightarrow{OA}+y \overrightarrow{OB}+z \overrightarrow{OC} \),则\(\left(x,y,z\right) \) 为
已知\(S\)是\(\triangle ABC\)所在平面外一点,\(D\)是\(SC\)的中点,若\(\overrightarrow{BD}=x\overrightarrow{AB}+y\overrightarrow{AC}+z\overrightarrow{AS}\),则\(x+y+z=\)__________.
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