Question Number 40122 by maxmathsup by imad last updated on 15/Jul/18
$${let}\:{u}_{{n}} =\:\sum_{{k}=\mathrm{0}} ^{{n}} \:\:\frac{\left(−\mathrm{1}\right)^{{k}} }{\left(\mathrm{2}{k}\right)!} \\ $$$${prove}\:{that}\:\left({u}_{{n}} \right)\:{converges} \\ $$