Question

Suma lui gaus :
S= 1+ 2 + 3 +..........+2015 va rog e urgent.

Answer 1

$\displaystyle 1+2+3+...+2015= \frac{2015(2015+1)}{2} = \frac{2015 \times 2016}{2} = \\ \\ = \frac{4062240}{2} =2031120$