Question Number 29980 by abdo imad last updated on 14/Feb/18
$${prove}\:{that}\:\gamma=\:\sum_{{n}=\mathrm{1}} ^{\infty} \:\:\left(\frac{\mathrm{1}}{{n}}\:\:−{ln}\left(\mathrm{1}\:+\frac{\mathrm{1}}{{n}}\right)\right) \\ $$$$\left.\mathrm{2}\right){show}\:{that}\:\gamma=\:\sum_{{k}=\mathrm{2}} ^{\infty} \:\:\frac{\left(−\mathrm{1}\right)^{{k}} }{{k}}\:\xi\left({k}\right). \\ $$