Question

Sn=1+3+5+7+.....+(2n+1) calculeaza suma

Answer 1

1+3+5+...+(2n+1)=(2*0+1)+(2*1+1)+(2*2+1)+.....+(2*n+1)= 2( 0+1+2+...+n) +n= 2*[n(n+1)]/2 + n = n(n+1)+n= n^2 + 2n

n^2 = n ridicat la puterea a doua