问题
填空题
若向量
|
答案
=AC
+AB BC
∵
•AC
=7n
∴(
+AB
)•BC
=7n
∴
•AB
+n
•BC
=7n
∵
=(3,-1),AB
=(2,1)n
∴
•AB
=5n
∴
•n
=7-5=2BC
故答案为:2
若向量
|
=AC
+AB BC
∵
•AC
=7n
∴(
+AB
)•BC
=7n
∴
•AB
+n
•BC
=7n
∵
=(3,-1),AB
=(2,1)n
∴
•AB
=5n
∴
•n
=7-5=2BC
故答案为:2