Calculati suma 1+3+5+.....+2n-1

Răspuns :

1+1+2+1+4+...+1+2n-2=
=((2n-1)+1)/2 + 2(1+2+3+...+(n-1))=
=n + 2(n-1)*n/2 =
=n + (n-1)*n =
=n*n
=n²