For a fixed real parameter

MATHEMATICS · Multi-part · AP · Calculus BC · Infinite Sequences and Series · Infinite Sequences and Series

Problem

For a fixed real parameter β\beta, examine the series R(β)=∑n=1∞n+βn2+1R(\beta)=\displaystyle \sum_{n=1}^{\infty} \dfrac{n+\beta}{n^{2}+1}. (a) Compute lim⁡n→∞n+βn2+1\displaystyle \lim_{n\to\infty} \dfrac{n+\beta}{n^{2}+1} in terms of β\beta. (b) Explain why the result from part (a) by itself neither confirms nor rules out convergence of R(β)R(\beta) for any value of β\beta. Provide a clear argument grounded in the properties of the limit you found. (c) Compare the general term of R(β)R(\beta) to 1n\dfrac{1}{n} for large nn, and discuss qualitatively what this comparison suggests about the convergence behavior of the series. No detailed proof beyond the discussion is required.

Related theory

Browse the problem library