[math] \newcommand{\ex}[1]{\item } \newcommand{\sx}{\item} \newcommand{\x}{\sx} \newcommand{\sxlab}[1]{} \newcommand{\xlab}{\sxlab} \newcommand{\prov}[1] {\quad #1} \newcommand{\provx}[1] {\quad \mbox{#1}} \newcommand{\intext}[1]{\quad \mbox{#1} \quad} \newcommand{\R}{\mathrm{\bf R}} \newcommand{\Q}{\mathrm{\bf Q}} \newcommand{\Z}{\mathrm{\bf Z}} \newcommand{\C}{\mathrm{\bf C}} \newcommand{\dt}{\textbf} \newcommand{\goesto}{\rightarrow} \newcommand{\ddxof}[1]{\frac{d #1}{d x}} \newcommand{\ddx}{\frac{d}{dx}} \newcommand{\ddt}{\frac{d}{dt}} \newcommand{\dydx}{\ddxof y} \newcommand{\nxder}[3]{\frac{d^{#1}{#2}}{d{#3}^{#1}}} \newcommand{\deriv}[2]{\frac{d^{#1}{#2}}{dx^{#1}}} \newcommand{\dist}{\mathrm{distance}} \newcommand{\arccot}{\mathrm{arccot\:}} \newcommand{\arccsc}{\mathrm{arccsc\:}} \newcommand{\arcsec}{\mathrm{arcsec\:}} \newcommand{\arctanh}{\mathrm{arctanh\:}} \newcommand{\arcsinh}{\mathrm{arcsinh\:}} \newcommand{\arccosh}{\mathrm{arccosh\:}} \newcommand{\sech}{\mathrm{sech\:}} \newcommand{\csch}{\mathrm{csch\:}} \newcommand{\conj}[1]{\overline{#1}} \newcommand{\mathds}{\mathbb} [/math]

Determine whether or not each of the following sequences [math]\{ s_n \}[/math] converges, and, if it does, evaluate the limit.

• [math]\cond{s_n = (-1)^n, & n=1,2,\ldots.}[/math]
• [math]s_n = \dilemma{1+\frac1n, & \mbox{for every integer [/math]n[math] such that [/math]1 \leq n \leq 10[math],}} {1, & \mbox{for every integer [/math]n > 10[math].}}[/math]
• [math]s_n = \dilemma{1+\frac1n, & \mbox{if [/math]n[math] is a positive even integer,}} {1, & \mbox{if [/math]n[math] is a positive odd integer.}}[/math]
• [math]s_n = \dilemma{1+\frac1n, & \mbox{for every integer [/math]n[math] such that [/math]1 \leq n \leq 10[math],}} {2, & \mbox{for every integer [/math]n > 10[math].}}[/math]