Term test for divergence
= Term test for divergence
If the terms $a_n$ of a series do not converge to zero, then $\sum_na_n$ diverges. This is the contrapositive of $a_n=S_n-S_{n-1}\to0$ for convergent partial sums.
= Term test for divergence
If the terms $a_n$ of a series do not converge to zero, then $\sum_na_n$ diverges. This is the contrapositive of $a_n=S_n-S_{n-1}\to0$ for convergent partial sums.