Formula for Relativistic Composition of Velocities

Velocity of A
with respect to C
= Velocity of A
with respect to B
+ Velocity of B
with respect to C
__________________________________
reduction factor

where

reduction factor =

    1 + (Velocity of A with respect to B/c)   x  (Velocity of B with respect to C/c)

 

Here's how the reduction factors for boosting light are computed. Take the simple case of composing 0.1c with c. the reduction factor is

1 + (0.1c/c)x(c/c) = 1 + (0.1)x(1) = 1.1

The other cases in the main text are computed correspondingly.