发布网友 发布时间:2022-04-29 17:33
共1个回答
热心网友 时间:2023-10-24 04:54
收敛半径R=lima/a=lim(3^n+5^n)(n+1)/{n[3^(n+1)+5^(n+1)]}(分子分母同除以n*5^n)=lim(1+1/n)[(3/5)^n+1]/[3*(3/5)^n+5]=1/5.当x=1/5时,级数为∑[(3/5)^n+1]/n>∑1/n,故发散;当x=-1/5时,级数为∑(-1)^n[(3/5)^n+1]/n>,收敛。则级数收敛域为x∈[-1/5,1/5)