已知overrightarrow (i)=(2,3,-1) , overrightarrow (i)=(2,3,-1)，overrightarrow (i)=(2,3,-1)，则overrightarrow (i)=(2,3,-1)等于（）

已知晶体原胞基矢为:overrightarrow ({a)_(1)}=dfrac (a)(2)overrightarrow (i)+dfrac (sqrt {3

设向量 overrightarrow (a)=(1,2,3) 、 overrightarrow (b)=(2,0,1), 则向量 overrightarrow

按第一行展开,行列式i j k-|||-1 2 3 =3overrightarrow (i)-3overrightarrow (j)-3overrightarr

设overrightarrow(a)=（1，-1，2），overrightarrow(b)=（3，-2，-1），则overrightarrow(a)×overr

已知(overrightarrow{OA)= overrightarrow(i)+ 3overrightarrow(k)}，(overrightarrow{OB

已知overrightarrow (E)=(overrightarrow (e)(x)_(1)+overrightarrow (e)({e)_(2))exp[

若向量 overrightarrow(AB)=(-1,2), overrightarrow(BC)=(3,-2), 则 overrightarrow(AC) 等

设 overrightarrow(a) = 3, 5, -2，overrightarrow(b) = 2, 1, 4，且已知 lambda overri

已知|overrightarrow(a)|=2，|overrightarrow(b)|=sqrt(3)，overrightarrow(a)与overrighta

已知overrightarrow(a)=(2,1,-1), overrightarrow(b)=(1,-1,2), 则overrightarrow(a)time