Question

calculati dau coroana
1+2+3+.......+90
1+2+3+....+180

Answer 1

[tex]Se~foloseste~formula~pentru~Suma~lui~Gauss. 1+2+3+...+n*(n+1):2 1+2+3+...+90=90*91:2=45*91=4095 1+2+3+...+180=180*181:2=90*181=16290[/tex]

Answer 2

$\boxed{ \frac{n(n+1)}{2} } \\ \text{Gauss, n este ultimul numar din sir.} \\ \\ 1+2+3+...+90= \frac{90*91}{2}=45*91=4095 \\ \\ 1+2+3+...+180= \frac{180*181}{2}=90*181=16290$