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12 Parabolic Cylinder FunctionsProperties

§12.4 Power-Series Expansions

12.4.1 U\left(a,z\right)=U\left(a,0\right)u_{1}(a,z)+U'\left(a,0\right)u_{2}(a,z),
12.4.2 V\left(a,z\right)=V\left(a,0\right)u_{1}(a,z)+V'\left(a,0\right)u_{2}(a,z),

where the initial values are given by (12.2.6)–(12.2.9), and u_{1}(a,z) and u_{2}(a,z) are the even and odd solutions of (12.2.2) given by

12.4.3 u_{1}(a,z)=e^{-\tfrac{1}{4}z^{2}}\left(1+(a+\tfrac{1}{2})\frac{z^{2}}{2!}+(a+%
\tfrac{1}{2})(a+\tfrac{5}{2})\frac{z^{4}}{4!}+\cdots\right),
12.4.4 u_{2}(a,z)=e^{-\tfrac{1}{4}z^{2}}\left(z+(a+\tfrac{3}{2})\frac{z^{3}}{3!}+(a+%
\tfrac{3}{2})(a+\tfrac{7}{2})\frac{z^{5}}{5!}+\cdots\right).

Equivalently,

12.4.5 u_{1}(a,z)=e^{\tfrac{1}{4}z^{2}}\left(1+(a-\tfrac{1}{2})\frac{z^{2}}{2!}+(a-%
\tfrac{1}{2})(a-\tfrac{5}{2})\frac{z^{4}}{4!}+\cdots\right),
12.4.6 u_{2}(a,z)=e^{\tfrac{1}{4}z^{2}}\left(z+(a-\tfrac{3}{2})\frac{z^{3}}{3!}+(a-%
\tfrac{3}{2})(a-\tfrac{7}{2})\frac{z^{5}}{5!}+\cdots\right).

These series converge for all values of z.