Fact2 is not true

since there may be a point on the line AB

         o                 o

o                 o                  o

         o                 o

A, left most point; B, right most point.

The central point C is not on unit circle A, nor on unit circle B. 

所有跟帖： 

• Since AB<>1, for any point C, either AC = 1, or BC =1. -wxcfan123- ♂ (0 bytes) () 08/13/2011 postreply 13:41:20

• or ABC is not triangle -15少- ♂ (0 bytes) () 08/13/2011 postreply 13:47:49

• For arbirary three points, at least one distance of a pair is 1. -wxcfan123- ♂ (67 bytes) () 08/13/2011 postreply 13:53:22

• It this is true, you can put any number points on one line. -wxcfan123- ♂ (0 bytes) () 08/13/2011 postreply 13:56:48

• sorry, i misunderstand the question -15少- ♂ (0 bytes) () 08/13/2011 postreply 14:09:50