Question Number 167471 by SANOGO last updated on 17/Mar/22
$${Montrer}\:{que} \\ $$$$\left({R}^{{n}} ,{d}_{\mathrm{1}} \right),\left({R}^{{n}} ,{d}_{\mathrm{2}} \right)\:{et}\left({R}^{{n}} ,{d}_{{oo}} \right) \\ $$$${sont}\:{des}\:{espaces}\:{metrique} \\ $$