
\magnification=\magstep2

$$
f(m)  \quad = \quad {{1}\over{2}} 
            \left( 
               1 - {
                     { \alpha (m - m_{\rm lim}) } \over 
                     { \sqrt { 1 + \alpha^2 (m - m_{\rm lim})^2 } }
                   }
            \right)
$$


\bye
