Question

calculeaza suma 11+22+33.....+198 metoda gauss

Answer 1

=11(1+2+3+,,,,+18)
=11(18x19:2)
=11x171
=1881

Answer 2

$11*1+11*2+11*3+....+11*18=$

$=11*(1+2+3+...+18)=$

$=11*\frac{18(18+1)}{2}=$

$=11*\frac{18*19}{2}=$

$=11*9*19=$

$=99*19=$

$=100*19-19=$

$=1900-19=$

$\boxed{=1881}$


OBS!!!

SUMA LUI GAUSS:

$\boxed{1+2+3+...+n=\frac{n(n+1)}{2}}$; n $\in$ |N