Chapter 12 - Sequences; Induction; the Binomial Theorem - 12.1 Sequences - 12.1 Assess Your Understanding - Page 807: 29

$\{s_n\}=\frac{1}{2^{n-1}}$

The pattern suggests that $\{s_n\}=\frac{1}{2^{n-1}}$. (Because $s_1=\frac{1}{1}=\frac{1}{2^{0}}$) Because the numerator is constantly $1$, and the denominator begins at $1$ and we can see that it gets multiplied by $2$ at each element.