³\begin{align*} \left ( x\left ( J_{m}J_{n}^{\prime }-J_{n}J_{m}^{\prime }\right ) \right ) ^{\prime } & =\left ( J_{m}J_{n}^{\prime }-J_{n}J_{m}^{\prime }\right ) +x\left ( J_{m}J_{n}^{\prime }-J_{n}J_{m}^{\prime }\right ) ^{\prime }\\ & =J_{m}J_{n}^{\prime }-J_{n}J_{m}^{\prime }+x\left ( J_{m}^{\prime }J_{n}^{\prime }+J_{m}J_{n}^{\prime \prime }-J_{n}^{\prime }J_{m}^{\prime }-J_{n}J_{m}^{\prime \prime }\right ) \\ & =J_{m}J_{n}^{\prime }-J_{n}J_{m}^{\prime }+x\left ( J_{m}J_{n}^{\prime \prime }-J_{n}J_{m}^{\prime \prime }\right ) \end{align*}