Chapter 9 - Conic Sections, Sequences, and Series - 9.3 Arithmetic Sequences - 9.3 Exercises - Page 727: 14

$-\frac{1}{5},\frac{1}{10},-\frac{1}{15},\frac{1}{20},-\frac{1}{25}$

$a_n=\frac{(-1)^n}{5n}$ $a_1=\frac{(-1)^1}{5\times1}=-\frac{1}{5}$ $a_2=\frac{(-1)^2}{5\times2}=\frac{1}{10}$ $a_3=\frac{(-1)^3}{5\times3}=-\frac{1}{15}$ $a_4=\frac{(-1)^4}{5\times4}=\frac{1}{20}$ $a_5=\frac{(-1)^5}{5\times5}=-\frac{1}{25}$