Daca sirul, bn, crescator nemarginit, atunci [tex] \lim_{n \to \infty} \frac{ a_{n} }{ b_{n} }= \lim_{n \to \infty} \frac{ a_{n+1}- a_{n} }{ b_{n+1}-b _{n} } [/tex]
Deci [tex] \lim_{n \to \infty}c_n= \lim_{n \to \infty} \frac{n}{2^n}= \lim_{n \to \infty} \frac{(n+1)-n}{ 2^{n+1}-2^n }= \lim_{n \to \infty} \frac{1}{2^n(2-1)}=0 [/tex]
