判断级数∑1/[(n+1)(2n+3)]的敛散性

题目

判断级数∑1/[(n+1)(2n+3)]的敛散性

答案

1/((n+1)(2n+3))<1/(n(n+1))=1/n-1/(n+1)
∑1/((n+1)(2n+3))<∑[1/n-1/(n+1)]<=1
级数收敛