Chapter 11 - Section 11.1 - Sequences - Exercise Set - Page 639: 9

$-1, -4, -9, -16, -25$

Let's evaluate $a_1, a_2, a_3, a_4, $and $a_5$ by plugging in $1, 2, 3, 4, $ and $5$ for each $n$. $a_1 = -(1^2) = -1$ $a_2 = -(2^2) = -4$ $a_3 = -(3^2) = -9$ $a_4 = -(4^2) = -16$ $a_5 = -(5^2) = -25$