问题
填空题
在△ABC中,A=90°,AB=6,且
|
答案
在△ABC中,∵A=90°,AB=6,且
=2CD
,DB
∴
•AB
=AD
•(AB
+AC
)CD
=
•(AB
+AC 2 3
)CB
=
•[AB
+AC
(2 3
-AB
)]AC
=
•(AB 1 3
+AC 2 3
)AB
=1 3
•AB
+AC 2 3
2AB
=
×0+1 3
•|2 3
|2AB
=
×622 3
=24.
故答案为:24.