(理)已知向量a=(3,5,-1),b=(2,2,3),c=(4,-1,-3),则向量2a-3b+4c的坐标为(  )A.(16,0,-23)B.(28,0,-

(理)已知向量a=(3,5,-1),b=(2,2,3),c=(4,-1,-3),则向量2a-3b+4c的坐标为(  )A.(16,0,-23)B.(28,0,-

题型:不详难度:来源:
(理)已知向量


a
=(3,5,-1),


b
=(2,2,3),


c
=(4,-1,-3),则向量2


a
-3


b
+4


c
的坐标为(  )
A.(16,0,-23)B.(28,0,-23)C.(16,-4,-1)D.(0,0,9)
答案
因为向量


a
=(3,5,-1),


b
=(2,2,3),


c
=(4,-1,-3),
所以向量2


a
-3


b
+4


c
=2(3,5,-1)-3(2,2,3)+4(4,-1,-3)=(16,0,-23).
故选A.
举一反三
已知A=(2,-4,-1),B=(-1,5,1),C=(3,-4,1),若


a
=


CA


b
=


CB
,则


a
+


b
对应的点为(  )
A.(5,-9,2)B.(-5,9,-2)C.(5,9,-2)D.(5,-9,-2)
题型:不详难度:| 查看答案
若A(2,-4,-1),B(-1,5,1),C(3,-4,1),则


CA


CB
=(  )
A.-11B.3C.4D.15
题型:不详难度:| 查看答案
已知


OA
=(1,2,3),


OB
=(2,1,2),


OC
=(1,1,2),点M在直线OC上运动,当


MA


MB
取最小值时,点M的坐标为______.
题型:不详难度:| 查看答案
已知向量


a
=(1-t,2t-1,0),


b
=(2,t,t)
,则|


a
-


b
|
的最小值是(  )
A.


2
B.


3
C.3D.2
题型:不详难度:| 查看答案
已知


a
=(2,3,5),


b
=(3,x,y),若


a


b
,则(  )
A.x=
9
2
,y=
15
2
B.x=9,y=15
C.x=
9
2
,y=15
D.x=-9,y=-15
题型:不详难度:| 查看答案
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