# Hankel H (2) in terms of csc and Bessel J

The following formula holds: $$H_{\nu}^{(2)}(z)=i\csc(\nu \pi) \left[ J_{-\nu}(z)-e^{\nu \pi i}J_{\nu}(z) \right],$$ where $H_{\nu}^{(2)}$ denotes the Hankel function of the second kind, $i$ denotes the imaginary number, $\csc$ denotes the cosecant, $J_{-\nu}$ denotes the Bessel function of the first kind, and $e^{\nu \pi i}$ denotes the exponential.