(In reply to solution
Your solution doesnt match what I found using Geometers Sketchpad, but I found your error.
x + (R-2T)/x is a minimum when x = sqrt(R-2t), not x+y as you stated.
x + y then simplifies to 2*sqrt(R-2t).
An interesting result, which I hadnt noticed is that this means x and y are precisely equal.
Posted by Jer
on 2010-10-14 15:15:37