Question

s-1+2+3+...+(n-2)+(n-1)+n dau coroana

Answer 1

Am anexat o rezolvare +++

Answer 2

Este celebra formulă a lui Gauss:

$\it S = 1+2+3+\ ...\ +n =\dfrac{n(n+1)}{2} \\ \\ \\ Exemplu: \\ \\ \\ 1+2+3+\ ...\ +19 = \dfrac{19\cdot20}{2} = 19\cdot10=190$