共50条信息
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\((\) \()\)
如图,在矩形\(ABCD\)中,\(AB=2\),\(BC= \sqrt{3} \),\(E\)是\(CD\)的中点,那么\( \overrightarrow{AE}· \overrightarrow{DC}= (\) \()\)
已知\(\overrightarrow{a}\cdot \overrightarrow{b}=12\),\(\left| \overrightarrow{a} \right|{=3,}\left| \overrightarrow{b} \right|{=5}\) ,则\(\overrightarrow{b}\)在\(\overrightarrow{a}\)方向上的投影为 .
设向量\( \overset{⇀}{a} \)、\( \overset{⇀}{b} \)满\( \overset{⇀}{a} ⋅ \overset{⇀}{b} =-8\),且向量\( \overset{⇀}{a} \)在向量\( \overset{⇀}{b} \)方向上的投影为\(-3 \sqrt{2} \),则\(| \overset{⇀}{b} |=\)
已知向量\( \overset{→}{a} \),\( \overset{→}{b} \)满足\(| \overset{→}{a}|=| \overset{→}{b}|=2 \),\( \overset{→}{a} \)与\( \overset{→}{b} \)的夹角为\(60^{\circ}\),则\( \overset{→}{b} \)在\( \overset{→}{a} \)上的投影是
已知\(|\)\(a\)\(|=4\),\(a\)与\(b\)的夹角为\( \dfrac{π}{6}\),则\(a\)在\(b\)方向上的投影为_____ ____.
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