回复：update

聪明的猫，应该会反向去追老鼠. So is a 聪明的鼠.
As you wrote, rat can always reach and run along a small circle r=5v in opposite to cat. let say cat is at (50,0), and rat is at (-5v,0). Then we can imagine that there is no benefit for cat to run reversely, when rat run toward any point P (at the big circle) with x less than -5v. (just because 聪明的猫，应该会反向去追老鼠. So is a 聪明的鼠.)

Now the key is to find the minimum v. I just found some mistakes in my fomula. It should be
v=10*((Squre root((PI+A)^2+(cosA)^2-1)-cosA)/((PI+A)^2-1)

I didn't how you find v>1 and v

所有跟帖： 

• 是我低估了老鼠的智商，对不起。以及v><1的解释 -koushi321- ♀ (1557 bytes) () 10/24/2008 postreply 08:53:39

• 最后一段没有贴全的在这里 -koushi321- ♀ (438 bytes) () 10/24/2008 postreply 09:02:36

• 还不行，再贴一次：最后一段没有贴全的在这里 -koushi321- ♀ (444 bytes) () 10/24/2008 postreply 09:05:37