$$W=J_{\nu }\left(z\right)Y_{\nu }^{\prime }\left(z\right)-Y_{\nu }\left(z\right)J_{\nu }^{\prime }\left(z\right)=Y_{\nu }\left(z\right)J_{\nu +1}\left(z\right)-J_{\nu }\left(z\right)Y_{\nu +1}\left(z\right)=\frac{2}{\pi z}$$