Question

Sa se calculeze: (n+1)+(n+2)+...+(n+n), n€ (apartinand lui) N* VA ROG❤❤ Dau coroana

Answer 1

[tex]S=n+1+n+2+n+3+...+n+n\\ S=1+2+3+...+n+n*n\\ S= \frac{n(n+1)}{2}+n^2\\ S= \frac{n(n+1)+2n^2}{2}\\ S= \frac{n(n+1+2n)}{2}= \frac{n(3n+1)}{2} [/tex]