Question Number 60493 by Mr X pcx last updated on 21/May/19
$${let}\:{f}\left({x}\right)=\sqrt{\mathrm{1}+\sqrt{\mathrm{1}+{x}^{\mathrm{2}} }} \\ $$$${approximate}\:{f}\left({x}\right)\:{by}\:{a}\:{polynome} \\ $$$${at}\:{v}\left(\mathrm{0}\right) \\ $$