问题
选择题
若O为平面内任一点,且满足(
|
答案
∵(
+OB
-2OC
)•(OA
-AB
)AC
=[(
-OB
)+(OA
-OC
)]•(OA
-AB
)AC
=(
+AB
)•(AC
-AB
)AC
=|
|2-|AB
|2=0,即|AC
|=|AB
|,AC
∴△ABC一定是等腰三角形.
故选A
若O为平面内任一点,且满足(
|
∵(
+OB
-2OC
)•(OA
-AB
)AC
=[(
-OB
)+(OA
-OC
)]•(OA
-AB
)AC
=(
+AB
)•(AC
-AB
)AC
=|
|2-|AB
|2=0,即|AC
|=|AB
|,AC
∴△ABC一定是等腰三角形.
故选A