I don't know which math forum to put this in but perhaps someone here could help out. I want to figure out the mathematics behind the Lorentz Transformation so I can understand it better. I've got a copy of Einstein's Relativity which was reprinted by Three Rivers Press a few years ago. In the Appendix there's a section on the Lorentz Transformation and I've hit a wall in figuring out the steps between the equations. On page 133 they have the following equation sets; (5) x' = ax - bct ct' = act - bx (6) v = bc/a On page 134 it gave an example where if a snapshot was taken from K'(t'=0) and t was removed from equations (5) where; x' = ax - bc 0 = ac - bx and taking into account expression (6), the following equation was derived; x' = a(1-(v^2/c^2))x Where did the (1-(v^2/c^2)) come from?