\[U\left(a,b,x\right)=\Gamma\left(\tfrac{1}{2}b-a+\tfrac{1}{2}\right)e^{\frac{1}%
{2}x}x^{\frac{1}{2}-\frac{1}{2}b}\*\left(\cos\left(a\pi\right)J_{b-1}\left(%
\sqrt{2x(b-2a)}\right)-\sin\left(a\pi\right)Y_{b-1}\left(\sqrt{2x(b-2a)}\right%
)+\operatorname{env}\mskip-2.0muY_{b-1}\left(\sqrt{2x(b-2a)}\right)O\left({%
\left|a\right|}^{-\frac{1}{2}}\right)\right),\]