Bob Cain wrote in message ...

Hi, Bob,

Just a minor correction.

Please notice the difference between what I wrote and what
Zigoteau wrote. His approach, a first order approximation
using a M-T power series, yields (using common symbols and
frames of reference):

Vp(d,t) = Vd(t - (d - Sd(t-d/c))/(c - Vd(t-d/c)))

Mine, which involves no approximation, yields:

Vp(d,t) = Vd(t - (d - Sd(t-d/c))/c)

I am sorry, Bob, but the second equation does involve an approximation.

Cheers,

Zigoteau.