"Donald Wilgus" wrote in message
m...
John,

Well, because he used a just "plane geometry" in his unique derivation.
No calculus, etc. I had heard that there might be a problem in the
approach
that he used. Before I really got into it, I wanted to know if there
really
was a problem.

Cheers,
Don W

Sorry, thought you were going somewhere else with this.

I'm going to engage in some hand waving here because I don't seem to be able
to find the references I want. (As such, I will happily stand corrected if
someone knows better)

I believe that any purely geometric treatment of the problem must,
necessarily, be just an approximation. The error associated with the
approximation can be made to be as small as we like, but when we start to do
this we are getting close to the realm were The Calculus steps into the
picture.