diff --git a/doc/src/Eqs/compute_shape_parameters.tex b/doc/src/Eqs/compute_shape_parameters.tex
new file mode 100644
index 0000000000..af7a6777f6
--- /dev/null
+++ b/doc/src/Eqs/compute_shape_parameters.tex
@@ -0,0 +1,12 @@
+\documentstyle[12pt]{article}
+
+\begin{document}
+
+\begin{eqnarray*}
+ c = l_z - 0.5(l_y+l_x) \\
+ b = l_y - l_x \\
+ k = \frac{3}{2} \frac{l_x^2+l_y^2+l_z^2}{(l_x+l_y+l_z)^2} - \frac{1}{2} 
+\end{eqnarray*}
+
+\end{document}
+