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Forum URL: http://www.cut-the-knot.org/cgi-bin/dcforum/forumctk.cgi
Forum Name: Guest book
Topic ID: 271
#0, 4 travelers
Posted by miguelb on Jul-27-03 at 01:27 AM
Dear Mr. Alexander Bogomolny:

First of all, I'd wish to congratulate you for this very good website.
My name is Miguel. I am from Porto Alegre, Brasil.
I have found another solution for the 4 travelers problem. It's in the attached zipped Word file.

Sincerely,


#1, RE: 4 travelers
Posted by alexb on Jul-27-03 at 01:36 AM
In response to message #0
LAST EDITED ON Jul-27-03 AT 02:18 PM (EST)
 
Thank you. At first sight, your doc file is incomplete. Except for (1), all other formulas are missing. I shall probably able to reconstruct the proof. Still it would be nice to have a complete submission.

#2, RE: 4 travelers
Posted by Vladimir on Jul-27-03 at 02:17 PM
In response to message #1
I have no problem viewing the attached document, including all equations, using WinZip 8.0 and Microsoft Word 2000.

Very nice proof.


#3, RE: 4 travelers
Posted by alexb on Jul-27-03 at 02:32 PM
In response to message #2
LAST EDITED ON Jul-27-03 AT 02:32 PM (EST)
 
>I have no problem viewing the attached document, including
>all equations, using WinZip 8.0 and Microsoft Word 2000.

It's all it took. Now, since I also use Word 2000, I went back to the document to check. All the formulas were present. I am mystified.

>Very nice proof.

The wording, though, must be corrected. We read (with a slight modification)

For (4) to be true for any values of V1 and V2, ...

But (4) need not be true for any values of the velocities, but only for some specific, albeit unknown, ones.

However, if we proceed with the substitutions that follow that sentence, we indeed prove (4), for the unknown velocities.

Very nice and simple.