Given number: e−n It is a series of species an(cx−x0)dn - power series. The radius of convergence of a power series can be calculated by the formula: Rd=cx0+limn→∞an+1an In this case an=1 and x0=−e , d=−1 , c=0 then R1=∞~(−e+n→∞lim1) Let's take the limit we find