Jacobi-Anger expansion
= Jacobi-Anger expansion
{c}
{title2=$e^{\mathrm iz\sin\theta}=\sum_{k\in\mathbb Z}J_k(z)e^{\mathrm ik\theta}$}
{wiki=Jacobi–Anger_expansion}
A <Fourier series> expansion of a sinusoidally modulated complex <wave phase> in <Bessel functions of the first kind>.