Question Number 136038 by frc2crc last updated on 18/Mar/21
$${Find}\:{a}_{{n}\:} {if} \\ $$$$\frac{\mathrm{1}}{{z}^{{m}} }×\mathrm{coth}\:\left(\pi{z}\right)×\mathrm{cot}\:\left({z}\pi\right)=\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}{a}_{{n}} {z}^{{n}} \\ $$$${around}\:{z}=\mathrm{0} \\ $$