Chapter 4 - Writing Linear Functions - 4.6 - Arithmetic Sequences - Exercises - Page 215: 35

$a_{n}=\frac{n}{2}$ $a_{10}=5$

The $n$th term is given by $a_{n}=a_{1}+(n-1)d$ where $a_{1}$ is the first term and $d$ is the common difference. Substituting $\frac{1}{2}$ for $a_{1}$ and $\frac{1}{2}$ for $d$, we get $a_{n}=\frac{1}{2}+(n-1)\frac{1}{2}$ Simplifying, we have $a_{n}=\frac{n}{2}$ Substituting $n=10$, we obtain $a_{10}=\frac{10}{2}=5$