共50条信息
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\(({ })\)
如图,点\(P\)为平行四边形\(ABCD\) 的边\(BC\)的中点,记\(\overrightarrow{AB}=a,\overrightarrow{BC}=b\),则( )
已知四边形\(ABCD\)是菱形,点\(P\)在对角线\(AC\)上\((\)不包括端点\()\),则\(\overrightarrow{AP}=(\) \()\)
已知\(| \overset{→}{OA} |=1\),\(| \overset{→}{OB} |=m\),\(∠AOB= \dfrac{3}{4} π\),点\(C\)在\(∠AOB\)内且\( \overset{→}{OA}· \overset{→}{OC} =0\),若\( \overset{→}{OC}=2λ \overset{→}{OA}+λ \overset{→}{OB} (λ\neq 0)\),则\(m=\)( )
已知\(\Delta ABC\)中,\(D\)是\(BC\)的中点,则\(3 \overrightarrow{AB}+2 \overrightarrow{BC}+ \overrightarrow{CA} =\)( )
已知\(\left| \overrightarrow{OA}\right|=\left| \overrightarrow{a}\right|=3,\left| \overrightarrow{OB}\right|=\left| \overrightarrow{b}\right|=3, ∠\)\(AOB\)\(=90^{\circ}\),则\(\left| \overrightarrow{a}+ \overrightarrow{b}\right| =\)________.
下列等式错误的是( )
如图,在四边形\(ABCD\)中,\(\overrightarrow{{DC}}{=}\dfrac{1}{3}\overrightarrow{{AB}}{,}E\)为\(BC\)的中点,且\(\overrightarrow{{AE}}{=}x\overrightarrow{{AB}}{+}y\overrightarrow{{AD}}\),则\(3x{-}2y{=}\) ______ .
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