（n+1）/(2n^4-1)的敛散性,请详细解答啊

（n+1）/(2n^4-1)的敛散性,请详细解答啊
（n+1）/(2n^4-1)的敛散性,请详细解答啊

（n+1）/(2n^4-1)的敛散性,请详细解答啊
级数(n＋1)/(2n^4-1)显然为正项级数；令an=(n＋1)/(2n^4-1),则an=(n＋1)/[n^4＋(n^4-1)]；当n＞1时,n^4-1＞0,所以an＜(n＋n)/(n^4),即an＜2/(n^3),级数2/(n^3)收敛,所以an收敛.