问题
填空题
已知:A(1,2,1),B(-1,3,4),C(1,1,1),
|
答案
设P(x,y,z)
∵A(1,2,1),B(-1,3,4,)
∴
=(x-1,y-2,z-1),AP
=(-1-x,3-y,4-z)PB
∵
=2AP PB
∴P(-
,1 3
,3)8 3
则|PC|=
=(1+
)2+(1-1 3
)2+(1-3)28 3 77 3
故答案为:77 3
已知:A(1,2,1),B(-1,3,4),C(1,1,1),
|
设P(x,y,z)
∵A(1,2,1),B(-1,3,4,)
∴
=(x-1,y-2,z-1),AP
=(-1-x,3-y,4-z)PB
∵
=2AP PB
∴P(-
,1 3
,3)8 3
则|PC|=
=(1+
)2+(1-1 3
)2+(1-3)28 3 77 3
故答案为:77 3