The series is alternating

MATHEMATICS · Subjective · AP · Calculus BC · Infinite Sequences and Series · Infinite Sequences and Series

Problem

The series

\displaystyle\sum_{n=1}^{\infty}(-1)^n\frac{n}{n+1}

is alternating. Identify which convergence condition it fails to meet and explain, in one sentence, what that means for the series’ convergence.