## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$=-1$
Rewrite the expression out as $(-1)^{13}=(-1)^2(-1)^2(-1)^2(-1)^2(-1)^2(-1)^2(-1)$ Since all the $(-1)^2$ values turn to $1$ (since $-1\cdot-1=1$), the only remaining value is $1 \cdot (-1)=-1$.