对于向量a,b,c,有().。 ()-|||-A )若 overrightarrow (a)cdot overrightarrow (b)=0, 则a,b中至少有一个零向量;-|||-B) (overrightarrow (a)+overrightarrow (b))cdot overrightarrow (c)=(overrightarrow (b)cdot overrightarrow (c))+(overrightarrow (a)cdot overrightarrow (c)) ;-|||-C) (overrightarrow (a)cdot overrightarrow (b))cdot overrightarrow (c)=overrightarrow (a)cdot (overrightarrow (b)cdot overrightarrow (c));-|||-D), (overrightarrow (a)cdot overrightarrow (b))(overrightarrow (a)cdot overrightarrow (b))=0.

16.设a,b是共线的单位向量,则 overrightarrow (a)cdot overrightarrow (b)=()-|||-

已知向量overrightarrow(a)=（0，1），overrightarrow(b)=（2，x），若overrightarrow(b)⊥（overrigh

3.已知向量overrightarrow(a)=(0,1),overrightarrow(b)=(2,x)，若overrightarrow(b)bot(b-4a

向量overrightarrow(a)、overrightarrow(b)、overrightarrow(c)两两垂直，且|overrightarrow(a)|

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

设overrightarrow(a)=（-1，1，2），overrightarrow(b)=（2，-2，-4），则向量|overrightarrow(a)×ov

(3)设 overrightarrow (a)=(-1,1,2) , overrightarrow (b)=(3,0,4) ,则向量a在向量b上的投影为(-||

若 overrightarrow (a)cdot overrightarrow (b)=0, 则k的值-|||-为 __-|||-(2)在 Delta ABC

在平面直角坐标系xOy中．已知向量overrightarrow(a)、overrightarrow(b)，|overrightarrow(a)|=|overri

10证明:若 overrightarrow (a)times overrightarrow (b)+overrightarrow (b)times overri