Question

as zice ca e marginit inferior de radical din n dar stiu ca trebuifolosite numere exacte nu litere la marginire.

Answer 1

$a_{n}= \sqrt{n}- \sqrt{n+1}= \frac{n-n-1}{ \sqrt{n}+ \sqrt{n+1}} = \frac{-1}{ \sqrt{n}+ \sqrt{n+1}},deci,-1\ \textless \ \frac{-1}{ \sqrt{n}+ \sqrt{n+1}} \ \textless \ 0$, deci $a_{n}$∈(-1;0)