Inductie. etapa verificrii n=1: 261=1=1 evident Se presupune Pn adevarat,se verifica daca Pn=>Pn+1 Pn 2^n≥n+1 ( A Pn+1 2^(n+1)≥(n+1)+1 <=>2·2^n≥n+2 <=> 2^n+2^n≥(n+1)+1 Dar 2^n≥n+1 conform (A si 2^n≥1 evident _______________ se aduna 2^n+2^n≥n+2 deci Pn=>Pn+1
