问题
选择题
若△ABC所在平面内一点P满足
|
答案
∵
=BC
-AC AB
又∵
=AP 1 2
+AB 1 2
-AC 1 6 BC
=1 2
+AB 1 2
-AC
(1 6
-AC
)AB
=1 3
+AB 2 3 AC
又∵
+1 3
=12 3
故P点一定在BC边上,
故选A
若△ABC所在平面内一点P满足
|
∵
=BC
-AC AB
又∵
=AP 1 2
+AB 1 2
-AC 1 6 BC
=1 2
+AB 1 2
-AC
(1 6
-AC
)AB
=1 3
+AB 2 3 AC
又∵
+1 3
=12 3
故P点一定在BC边上,
故选A