La primul exercitiu dai factor comun fortat pe n² sub radical an=[lnl*√(1+1/n²)+4lnl√(1+1/n+1/n²)]n= n*[√(1+1/n²)+√1+1/n+1/n²)/n=√(1+1/n²)+√(1+1/n+1/n²)=1+1=2 --------------------------------------------------------------- 1²+...+n²=n*(n+1)*(2n+1)/6→∞
