Question

Aratai ca numarul 2+4+6+..............+2n nu este patrat perfect

Answer 1

2+4+6+...+2n = 2(1+2+3+...+n)= 2(n·(n+1))/2 = n· (n+1) = n²+n  nu e patrat perfect
n (n+1) nu e patrat perfect pt ca e cuprins intre n² si nr  (n+1)²

Answer 2

$2+4+6+...+2n=2(1+2+3+...+n)=2* \frac{n(n+1)}{2} =n^2+n$