Wn,3(u,ξ)=|ξ|1/2Jν(u|ξ|1/2)(s=0n1As(ξ)u2s+O(1u2n1))|ξ|Jν+1(u|ξ|1/2)(s=0n2Bs(ξ)u2s+1+O(1u2n2)),