共50条信息
已知向量\(a=(1,m)\),\(b=(3,-2)\),且\(\left(a+b\right)⊥b \),则\(m=\)( )
已知向量\(\overset{\to }{{BA}}\,\)\(=(\)\(\dfrac{1}{2}\),\(\dfrac{\sqrt{3}}{2}\)\()\),\(\overset{\to }{{BC}}\,\)\(=(\)\(\dfrac{\sqrt{3}}{2}\),\(\dfrac{1}{2}\)\()\),则\(∠ABC=\)( )
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