Question

Rezolvati inecuatia 2xcombinari de 2 luate de n ori < n+8. Dau coroana celui care raspunde mai repede! :-)

Answer 1

$2\ C_2^{n} \ \textless \ n+8 \\\\ n \geq 0 \to n \in [0;+ \infty) \\ 2 \geq n \to n \in (-\infty;2] \\\\ n \in N \\\\\\ \Longrightarrow D=[0;2] \\\\\\ 2* \frac{2!}{n!(2-n)!} \ \textless \ n+8 \\\\ \frac{4}{n!(2-n)!}\ \textless \ n+8 \\\\ Pt \ n=0 \ \longrightarrow \frac{4}{1*2!}\ \textless \ 8 \ \textless \ =\ \textgreater \ 2\ \textless \ 8 \ \ "A" .\\.\\.\\.\\\\ n=3 \longrightarrow \frac{4}{3!(2-3)!}\ \textless \ 11 \ \ \ "F" \\\\\ \Longrightarrow S_n= \{0;1;2 \}$