$\lim_{n \to \infty} |\frac{a_{n+1}}{a_n}| < 1$

$\lim_{n \to \infty} |\frac{a_{n+1}}{a_n}| > 1$

$\lim_{n \to \infty} |\frac{a_{n+1}}{a_n}| = 1$

$\lim_{n \to \infty} |\frac{a_{n+1}}{a_n}| = 0.5$