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10 Bessel FunctionsBessel and Hankel Functions

§10.12 Generating Function and Associated Series

For z\in\mathbb{C} and t\in\mathbb{C}\setminus\{0\},

10.12.1 e^{\frac{1}{2}z(t-t^{-1})}=\sum_{m=-\infty}^{\infty}t^{m}J_{m}\left(z\right).

Jacobi–Anger expansions: for z,\theta\in\mathbb{C},

10.12.2
\cos\left(z\sin\theta\right)=J_{0}\left(z\right)+2\sum_{k=1}^{\infty}J_{2k}%
\left(z\right)\cos\left(2k\theta\right),
\sin\left(z\sin\theta\right)=2\sum_{k=0}^{\infty}J_{2k+1}\left(z\right)\sin%
\left((2k+1)\theta\right),
10.12.3
\cos\left(z\cos\theta\right)=J_{0}\left(z\right)+2\sum_{k=1}^{\infty}(-1)^{k}J%
_{2k}\left(z\right)\cos\left(2k\theta\right),
\sin\left(z\cos\theta\right)=2\sum_{k=0}^{\infty}(-1)^{k}J_{2k+1}\left(z\right%
)\cos\left((2k+1)\theta\right).
10.12.4 1=J_{0}\left(z\right)+2J_{2}\left(z\right)+2J_{4}\left(z\right)+2J_{6}\left(z%
\right)+\dotsb,
10.12.5
\cos z=J_{0}\left(z\right)-2J_{2}\left(z\right)+2J_{4}\left(z\right)-2J_{6}%
\left(z\right)+\dotsb,
\sin z=2J_{1}\left(z\right)-2J_{3}\left(z\right)+2J_{5}\left(z\right)-\dotsb,
10.12.6
\tfrac{1}{2}z\cos z=J_{1}\left(z\right)-9J_{3}\left(z\right)+25J_{5}\left(z%
\right)-49J_{7}\left(z\right)+\dotsb,
\tfrac{1}{2}z\sin z=4J_{2}\left(z\right)-16J_{4}\left(z\right)+36J_{6}\left(z%
\right)-\dotsi.