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+\documentclass[12pt]{article}
+\pagestyle{empty}
+
+\begin{document}
+
+\begin{eqnarray*}
+\phi\left(r\right) & = &  D_0 \left[ e^{- 2 \alpha (r - r_0)} - 2 e^{- \alpha (r - r_0)} \right] \qquad r < r_c \\
+E\left(r\right) & = & \phi\left(r\right)  - \phi\left(R_c\right) - \left(r - R_c\right) \left.\frac{d\phi}{d r} \right|_{r=R_c}       \qquad r < R_c 
+\end{eqnarray*}                           
+
+\end{document}
+
+