Figure

$\sum\limits_{k\,=\,1}^{\infty }87$ diverges, since $\lim\limits_{n\,\rightarrow \,\infty }87=87\neq 0$ .
$\sum\limits_{k\,=\,1}^{\infty }k$ diverges, since $\lim\limits_{n\,\rightarrow \,\infty }n=\infty \neq 0$ .
$\sum\limits_{k\,=\,1}^{\infty }(-1)^{k}$ diverges, since $\lim\limits_{n\,\rightarrow \,\infty }\,(-1)^{n}$ does not exist.
$\sum\limits_{k\,=\,1}^{\infty }2^{k}$ diverges, since $\lim\limits_{n\,\rightarrow \,\infty }\,2^{n}=\infty \neq 0$ .