 $${ \lim _{\varepsilon \searrow 0}}\frac{{ \rho ^\varepsilon _0}}{{ \varepsilon}} = \frac{|A|}{\alpha},\;\;{ \lim _{\varepsilon \searrow 0}}\frac{r - { \rho ^\varepsilon _0}}{{ \varepsilon}} = \frac{|A|}{0\alpha}