\[\frac{J_{\nu}\left(z\right)}{J_{\nu-1}\left(z\right)}=\cfrac{\tfrac{1}{2}z/\nu%
}{1-\cfrac{\tfrac{1}{4}z^{2}/(\nu(\nu+1))}{1-\cfrac{\tfrac{1}{4}z^{2}/((\nu+1)%
(\nu+2))}{1-\cdots}}},\]