Index: sparse_sample/damkjer_sparse_sample.tex
===================================================================
--- sparse_sample/damkjer_sparse_sample.tex	(revision 0)
+++ sparse_sample/damkjer_sparse_sample.tex	(revision 1)
@@ -75,4 +75,12 @@
 \subsection{Normal Estimation}
 Perform normal estimation by planar fit to point data.
+
+\begin{align}
+\textbf{x}_{i} = \left(\begin{array}{ccc}x_{i}&y_{i}&z_{i}\end{array}\right)^{T}
+\end{align}
+\begin{align}
+\overline{\textbf{x}} = \dfrac{1}{n}\sum_{i=1}^{n}{\textbf{x}_i}
+\end{align}
+
 
 \cite{Dey:2005}