\magnification=\magstep1

$$
{ {1}\over{{\rm E}_f } } -  { {1}\over{{\rm E}_i}} \quad = \quad
     {{1}\over{ {\rm m_e c^2} }} \thinspace (1 - \cos \theta) 
$$
   

$$
{\rm E}_f \quad \sim \quad {\rm E}_i \thinspace \left( {{2}\over{1 - v/c}} \right) 
$$

$$
{\rm Lorentz\ factor\ } \gamma \quad = \quad 
                     {{1} \over { \sqrt{ {1 - {{v^2}\over{c^2}}}} } }
$$

\bye

