An arithmetic series is the sum of an arithmetic sequence. In this lesson, we will learn how to solve problems using the arithmetic series formula.

• the sum of $n$ terms of an arithmetic series:

${s_n}$= $\frac{n}{2}[2{t_1} + (n - 1)d]$

= $\frac{n}{2}[{t_1} + {t_n}]$

${s_n}$= $\frac{n}{2}[2{t_1} + (n - 1)d]$

= $\frac{n}{2}[{t_1} + {t_n}]$