)}$ are both bounded, continuous functions on a compact domain (the interval $[x_0 x_0]$), we need only show that the following limit exists: $$\label{mu-def-limit}       \lim_{a \to b} \frac{\left| \sqrt{{\ensuremath{D_{s\phi}}}(q,a)} - \sqrt{{\ensuremath{D_{s\phi}}}(q,b)} \right|