优优班--学霸训练营 > 知识点挑题
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            • 1.

              称\(d(a,b)=|a-b|\)为两个向量\(a\),\(b\)间的“距离”\(.\)若向量\(a\),\(b\)满足:\(①|b|=1\);\(②a\neq b\);\(③\)对任意的\(t∈R\),恒有\(d(a,tb)\geqslant d(a,b)\),则(    )

              A.\(a⊥b\) 
              B.\(b⊥(a-b)\)

              C.\(a⊥(a-b)\) 
              D.\((a+b)⊥(a-b)\)
            • 2.

              两个大小相等的共点力\(F_{1}\),\(F_{2}\),当它们夹角为\(120^{\circ}\)时,合力大小为\(3\sqrt{2}N\),则当它们夹角为\(90^{\circ}\)时,合力大小为

              A.\(3\sqrt{2}N\)
              B.\(6N\)
              C.\(\dfrac{3\sqrt{6}}{2}N\)
              D.\(3\sqrt{6}N\)
            • 3.

              如图\(2\),“六芒星”是由两个全等正三角形组成,中心重合于点\(O\),且三组对边分别平行\(.\)点\(A\),\(B\)是“六芒星”\((\)如图\(1)\)的两个顶点,动点\(P\)在“六芒星”上\((\)内部以及边界\()\),若\(\overrightarrow{OP}=x\overrightarrow{OA}+y\overrightarrow{OB}\),则\(x+y\)的取值范围是

              A.\([-4,4]\)
              B.\(\left[- \sqrt{21}, \sqrt{21}\right] \)
              C.\([-5,5]\)
              D.\([-6,6]\)
            • 4.

              在\(\vartriangle ABC\)中,\(N\)为线段\(AC\)上靠近\(A\)的三等分点,点\(P\)在\(BN\)上且\(\overrightarrow{AP}{=}(m+\dfrac{2}{11})\overrightarrow{AB}+\dfrac{2}{11}\overrightarrow{BC}\),则实数\(m\)的值为\((\)    \()\)

              A.\(\dfrac{1}{2}\)
              B.\(\dfrac{5}{11}\)
              C.\(\dfrac{9}{11}\)
              D.\(1\)
            • 5.

              已知\(D\),\(E\),\(F\)分别是\({\triangle }{ABC}\)的边\(AB\),\(BC\),\(CA\)的中点,则下列等式中不正确的是\(({  })\)

              A.\(\overrightarrow{{FD}}{+}\overrightarrow{{DA}}{=}\overrightarrow{{FA}}\)
              B.\(\overrightarrow{{FD}}{+}\overrightarrow{{DE}}{+}\overrightarrow{{EF}}{=}\overrightarrow{0}\)
              C.\(\overrightarrow{{DE}}{+}\overrightarrow{{DA}}{=}\overrightarrow{{EC}}\)
              D.\(\overrightarrow{{DA}}{+}\overrightarrow{{DE}}{=}\overrightarrow{{FD}}\)
            • 6.

              已知\(A\),\(B\)是圆\(O:x^{2}+y^{2}=16\)上的两个动点,且\(|AB|=4\),\(\overrightarrow{OC}=\dfrac{{5}}{{3}}\overrightarrow{OA}-\dfrac{{2}}{{3}}\overrightarrow{OB}\),若\(M\)是线段\(AB\)的中点,则\(\overrightarrow{OC}\cdot \overrightarrow{OM}=\)

              A.\({8}+{4}\sqrt{{3}}\)
              B.\({8}-{4}\sqrt{{3}}\)
              C.\(12\)
              D.\(4\)
            • 7.

              已知四边形\(ABCD\)是菱形,点\(P\)在对角线\(AC\)上\((\)不包括端点\()\),则\(\overrightarrow{AP}=(\)  \()\)

              A.\(λ(\overrightarrow{AB}+\overrightarrow{AD})\),\(λ∈(0,1)\)

              B.\(λ(\overrightarrow{AB}+\overrightarrow{BC})\),\(λ∈(0, \dfrac{ \sqrt{2}}{2})\)

              C.\(λ(\overrightarrow{AB}-\overrightarrow{AD})\),\(λ∈(0,1)\)

              D.\(λ(\overrightarrow{AB}-\overrightarrow{BC})\),\(λ∈(0, \dfrac{ \sqrt{2}}{2})\)
            • 8.

              在正六边形\(ABCDEF\)中,若\(\overset{⇀}{AB}= \overset{⇀}{a} \),\(\overset{⇀}{AE}= \overset{⇀}{b} \),则\(\overset{⇀}{BC}= \)              \(.(\)用\(\overset{⇀}{a} \),\(\overset{⇀}{b} \)表示\()\)

            • 9.
              已知在\(\triangle ABC\)中,\(AB=1\),\(BC= \sqrt {6}\),\(AC=2\),点\(O\)为\(\triangle ABC\)的外心,若\( \overrightarrow{AO}=s \overrightarrow{AB}+t \overrightarrow{AC}\),则有序实数对\((s,t)\)为\((\)  \()\)
              A.\(( \dfrac {4}{5}, \dfrac {3}{5})\)
              B.\(( \dfrac {3}{5}, \dfrac {4}{5})\)
              C.\((- \dfrac {4}{5}, \dfrac {3}{5})\)
              D.\((- \dfrac {3}{5}, \dfrac {4}{5})\)
            • 10. 在平行四边形\(ABCD\)中,\(∠BAD=60^{\circ}\),\(AD=2AB\),若\(P\)是平面\(ABCD\)内一点,且满足\((x,y∈R)\),则当点\(P\)在以\(A\)为圆心,为半径的圆上时,实数\(x\),\(y\)应满足关系式为\((\)  \()\)
              A.\(4x^{2}+y^{2}+2xy=1\)
              B.\(4x^{2}+y^{2}-2xy=1\)
              C.\(x^{2}+4y^{2}-2xy=1\)
              D.\(x^{2}+4y^{2}+2xy=1\)
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