问题
填空题
已知△ABC是边长为1的等边三角形，P为边BC上一点，满足
|
答案
∵
=2PC
，∴BP
=BP 1 3
．BC
∴
•AB
=AP
•(AB
+AB
)=BP
2+AB
•AB 1 3
=1+BC
|1 3
| |AB
|cos120°=1+BC
×1×1×(-1 3
)=1 2
．5 6
故答案为
．5 6
搜题请搜索小程序“爱下问搜题”
已知△ABC是边长为1的等边三角形，P为边BC上一点，满足
|
∵
=2PC
，∴BP
=BP 1 3
．BC
∴
•AB
=AP
•(AB
+AB
)=BP
2+AB
•AB 1 3
=1+BC
|1 3
| |AB
|cos120°=1+BC
×1×1×(-1 3
)=1 2
．5 6
故答案为
．5 6