已知(overrightarrow{OA)= overrightarrow(i)+ 3overrightarrow(k)}，(overrightarrow{OB)= overrightarrow(j)+ 3overrightarrow(k)}，则(triangle OAB)的面积为( )

[题目]已知 overrightarrow (OA)=i+3k, overrightarrow (OB)=overrightarrow (j)+3k 求 Del

overrightarrow (a)=overrightarrow (i)-2overrightarrow (j)+3overrightarrow (k) 在y

8.已知 overrightarrow (OA)=i+3k, overrightarrow (OB)=j+3k, 求 Delta ABO 的面积.

[题目]向量 overrightarrow (a)=-overrightarrow (i)+2overrightarrow (j)+overrightarrow

一质点的运动方程为overrightarrow (r)(t)=3overrightarrow (i)-7toverrightarrow (j)+2(t)^3ov

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

已知|overrightarrow(a)•overrightarrow(b)|=3，|overrightarrow(a)×overrightarrow(b)|=

若矢量 overrightarrow (a)+3overrightarrow (b) 垂直于 overrightarrow (a)-5overrightarro

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

已知质点的运动方程为=5(t)^2overrightarrow (i)+3toverrightarrow (j)+4overrightarrow (k)，则=5