问题 填空题
已知平面内四点O,A,B,C满足2
OA
+
OC
=3
OB
,则
BC
|
AB
|
=______.
答案

∵2

OA
+
OC
=3
OB

OC
-
OB
=2(
OB
-
OA

OC
-
OB
=
BC
OB
-
OA
=
AB

BC
=2
AB

可得向量

BC
与向量
AB
方向相同,且
BC
模是
AB
模的2倍

BC
|
AB
|
=2.

故答案为:2

单项选择题 A型题
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