# H (1/2)(z)=sqrt(2/(pi z))(1-cos(z))

The following formula holds: $$\mathbf{H}_{\frac{1}{2}}(z) = \sqrt{\dfrac{2}{\pi z}}(1-\cos(z)),$$ where $\mathbf{H}_{\frac{1}{2}}$ denotes a Struve function, $\pi$ denotes pi, and $\cos$ denotes cosine.