1. The problem statement, all variables and given/known data For a particle traveling near the speed of light, find the first non-vanishing term in the expansion of the relative difference between the speed of the particle and the speed of light, (c-v)/c, in the limit of very large momentum p>>mc. Hint: Use (mc/p) as a small parameter for your expansion. 3. The attempt at a solution I know the answer is (1/2)(mc/p)^2, but I'm not sure where this answer comes from. I understand the basic idea of expansions, however, I'm not sure as to what "in the limit of very large momentum" means. Can someone guide me through this problem?