For what r does 3n2r33n converge or diverge?

1 Answer
May 29, 2016

The series sum converges only for r=2

Explanation:

This series can be decomposed as the sum of two series: na1n=n3n2r3 and na2n=n3n so that nan=n(a1n+a2n). The series na2n is allways divergent and na1n converges or diverges depending on r. So nan is convergent only for r=2 when a1n+a2n=0